Hack Your Biological Clock: Light-Induced Circadian Phase Shifts Work So Well That You Better Watch Out to Avoid Accidental Phase Shifting When You Check Your Mails

If you do it on purpose, "hacking" your biological clock can be highly beneficial. If you're doing it out of pure ignorance, though, you're in trouble.

In view of the impeding return to standard time, it's probably a good thing, in view of the iPhones, iPads and Facebooks of this world it could turn out to be a serious health problem, though: the ease with which you can "hack" your biological clock - on purpose, but also incidentally.

How easy it really is to turn the biological clock of life forward and backward has in fact only recently  been confirmed by Seong Jae  Kim and colleagues from the Northwestern University Feinberg School of Medicine and the Technology Evaluation Center of BlueCross BlueShield Association (Kim. 2013)

Fast forward / backward, please!

All the scientists had to do to make sure that the 29 healthy young (25.1 ± 4.1 years, M:F=8:21) and 16 healthy older subjects (66.5 ± 6.0 years, M:F=5:11) who participated in the said study experienced a 2h shift in the onset of their natural melatonin release was to expose them in a randomized order to 2h light pulses of 2 different intensities: 2,000  and  8,000lux)

Figure 1: Graphical summary of the implications you of the data from Kim et al. (2013)

As you can see in the graphical illustration of the implications in Figure 1 the scientists used the core body temperature minimum (CBT_min) of their subjects as a reference.

Suggested Read: "90 Min Sleep Restriction - How Bad is It Really? Changes in Insulin Resistance Last For One Week" | more

"Subjects were admitted for four nights and three days under dim light during daytime hours with eight hours of sleep in dark at their habitual time (dark bars). Blood samples were taken throughout the baseline and post -treatment nights to assess lightinduced [sic!] changes in the circadian melatonin rhythm.

On the third night, subjects were exposed to light at one of 3 time points ( -8h, -3h, or 3h) relative to the core body temperature minimum (CBTmin) measured on the baseline night. They were exposed to a 2-hour light pulse (including a 15 min ramp up and ramp down) of 2,000 lux on one laboratory stay and 8,000 lux on a different laboratory stay, in a randomized order, separated by at least 3 weeks." (Kim. 2013)

I guess it may come as a surprise that the scientists were able to show that the effect size / efficiency of the procedure was significantly influenced by the time of pulse, but not by its intensity, the age of the subjects or interactions between age and intensity, or time of pulse and intensity.

What did make a difference, though was the lag (=length of the time shift that was achieved), though.  Administered -8h before core body temperature minimum (CBT) the average phase delays  were -0.72h for  2,000lux and -0.50h for  8,000lux. When it was administered +3h after the CBT the researchers observed only a minimal phase advance of +0.05h for  2,000lux, while the 8,000 lux light produced a phase shift of + 0.18 h. In both cases the standard deviations were however so large that a significant difference could not be found.

8h is where the sweet spot it + phase advances are difficult to achieve

The "wake-up protocol" (Figure 1, 2nd row on night 3), in the course of which the subjects were woken up 3h before the CBT and thus while they were already sleeping had paradoxical and unpredictable effects:

"Light exposure targeted 3h before CBT min was distributed in both phase delay and advance regions  (-3.2h to +2.5h) relative to the melatonin midpoint." (Kim. 2013)

Needless to say that this is not a suggested protocol, but a good example of the mess that happens, when your sleep gets interrupted by light exposure.In other words, the procedure is identical irrespective of your age and the "power" of the lamp you use - the one thing that counts is the timing of the pulses.

How intense is the light around me? In order to give you a better idea of how intense 2,000 and 8,000lux are, I've compiled a couple of reference values:

• Dim interior lighting < 100 lux
• Residential indoor lighting < 500 lux
• Bright indoor lighting (e.g. task lighting, kitchens, offices, stores) < 1,500 lux
• Sunlight + cloudy sky + shadow < 5,000 lux
• Sunlight + in shadow < 10,000 lux
• Full, but not direct daylight daylight < 25,000 lux
• Outdoor direct sunlight < 120,000 lux

Don't forget that the frequency (=color) of the light is about as important as its intensity; only blue / green light and light with blue and/or green components (e.g. the light of an LED display) will get the job done.

In the discussion of their results, the researchers point out that their findings are in line with previous studies by Duffy et al. (Duffy. 2007), ...

"[...]who found that there was no difference between young and older adults in the magnitude of  phase delays of the melatonin rhythm following 6.5 hour light exposure of more than 1,000 lux." (Kim. 2013)

They also reference a study by Sletten et al. (2009) that compared the effectiveness of blue and green light in young and older adults. In the said study, the researchers determined that the phase advances in response to blue light were  slightly larger than advances in response to green light in both young and older adults. The perceived effects on subjective alertness and sleepiness, on the other hand, were significantly more pronounced in the younger participants in the blue light condition.

As Kim et al. point out, their own previous analysis seem to indicate that blue light is much more effective, when it comes to the induction of phase advances than green light - in fact, in one of their studies, the exposure the use of green and red light did not yield satisfying results at all (Green. 2004).

So does this mean you have to use one of the fancy blue-light lamps?

Despite the fact that there is little doubt that "blue" (~430nm) light is more effective than green light and that red light does not work at all, you may be shocked to hear that running Facebook on your laptop screen is probably enough to get the job done.

The reasons are simple: Firstly, what you see there is "blue" or at least "blueish", anyway. More importantly, however, the fancy LCD and LED displays in modern notebooks, tablet PCs and smartphones have an outstanding luminosity (=they are bright enough) and, as you can easily see in the graphs below, "blue enough".

WLED

GB-LED

How bad is it? It really depends on the "how blue" your screen is going to be. Many cheaper LED monitors use the "blueish" WLED technology - the "true color" GB-LED displays are mostly used, where true color actually matters - in print and design.

The spectral data does also tell you that you will never "lack" blue light to convince your body that it's time to rise and shine, not time to sleep, even if you have one of the modern "true color" displays. Much contrary to the clock in the lower right of your screen, your biological clock will thus basically freeze in "daylight mode" the very moment you sit down in front of your screen.

Yes, things can become worse - you don't even have to sit there for hours

I know what you're thinking, you, a SuppVersity Veteran from hour one, obviously new all that and the only thing you do after 8PM, to make sure you can be in bed ad 10PM and get your 8h of sleep before you have to shower at 6AM on the next morning is to check the occasional text massage on your phone, right? Well, bad news:

"According to published data, a phase shift is often not completed immediately after a light pulse (Pittendrigh et al., 1958; Watanabe et al., 2001)." (Kim. 2013)

Actually the saturation effect, i.e. the presence of identical phase shifts for 2,000 and 10,000 lux, confirms it: It does not take hours to biohack yourself!

It goes without saying that this is a good thing, if you actually plan to advance / delay the onset of melatonin release, it is however a serious problem if you "just head back to check your emails" right before you are heading to bed.

So how do you "biohack" your rhythm, then? If you want to try the no guesswork approach, the first thing you would have to do is to try and find your core body temperature minimum. Unfortunately, this is - despite the existent correlation with oral, rectal and gut temperature - not an exactly easy undertaking, as it will occur right when you are supposed to sleep, not to fumble around with a thermometer.

Use fasting another means to sync your internal (light control) and peripheral biological clock. Learn more in the last installment of the Circadian Rhtythmicity Series: "Intermittent Fasting (Re-)Sets the Peripheral Clock" | read more

So we just assume that his would be at ~4am (where it should be if you lived by the natural clock, i.e. sunrise and -set), which would mean that you would be able to master ...

• the impeding -1h phase shift on Sunday (US 11/03 vs. EU 10/27) at 3:00 (AM) by sitting in front of an appropriately bright light from 6pm to 8pm, and  
• the subsequent +1h phase shift in spring by sitting in front of a bright light on Thursday, Friday and Saturday morning at 7am for 2h

Actually, both does not appear so difficult, right? And I bet that some of you are in fact inducing a decent phase delay on a regular basis when they sit in front of a bright computer or television screen after sundown. Am I right? If so: Is it really any wonder you always wake up unrefreshed when your alarm clock rings?

References:

• Longo DL et al. Harrison's Online. Featuring the complete contents of Harrison's Principles of Internal Medicine, 18e.
• Kim SJ, Benloucif S, Reid KJ, Weintraub S, Kennedy N, Wolfe LF, Zee PC. Phase-shifting Response to Light in Older Adults. J Physiol. 2013 Oct 21. [Epub ahead of print]
• Sletten TL, Revell VL, Middleton B, Lederle KA, Skene DJ. Age-related changes in acute and phase-advancing responses to monochromatic light. J Biol Rhythms. 2009 Feb;24(1):73-84.

Circadian Rhythmicity - Sunlight a La Carte: How to "Hack" Your Circadian Rhythm With 30min of Light Therapy Per Day

Image 1: The last installment was all about avoiding artificial  light, today we will use it to our advantage.

In the last installment of the SuppVersity Circadian Rhythm Series, we have taken a brief look at some of the physical aspects of light, in general, and how they relate to the physiological effects sunlight and artificial light exert on our biological clock. We have identified the omnipresence of unnatural "light" (in the broadest sense)  in our 24/7 x 365 world as one of the, if not the most important reason that our natural circadian rhythm and all the metabolic and endocrine parameters that depend on it got out of balance and we have discussed a couple of things that could be useful for anyone to either regain or retain the natural rhythm our genes have evolved with. In today's installment we are now (figuratively) turning back the time and take a look at the beneficial effects the same light(s) that keep(s) us awake, when we are long supposed to sleep, can have on the accuracy of our biological clock, earlier in the day.

Let the sun shine in your eyes to feel it in your heart ;-)

Now, that the day's are long and the sun is up or at least about to rise, when we are making our way to the bathroom to shower, brush our teeth, brew our coffee and grab something to eat (or continue our fast) before we pour ourselves into our daily business, many of you may already have forgotten those dark winter days, when you leave the house in darkness and sit in the office all day and are happy to see the last rays of the sun, when you jump into your car and head home, to the gym or to wherever you may be going on an "afternoon", your body can hardly distinguish from the darkest night.

Image 2: Selected physiological functions and their circadian pattern (Richter. 2011).

Scientists have long coined a specific term for this syndrome: Seasonal affective (SAD). Despite the fact that SAD has become more or less synonymous with the dreaded "winter blues", however, the depressive mood many people experience during the winter months, may be the most prominent, but certainly ain't the only symptom of a whole set of pathologies that are directly or indirectly related to a mismatch between your biological and social clocks. Against the background that the former controls a whole host of very important physiological processes (see image 2), it stands to reason that the consequences of this mismatch are not restricted to psychological problems. Moreover,  the number of patients and non-patients, i.e. people who simply regard symptoms such as...

• sleep problems - oversleeping but not refreshed, cannot get out of bed, napping in the afternoon
• overeating - carbohydrate craving leading to weight gain
• depression, despair, misery, guilt, anxiety - normal tasks become frustratingly difficult
• family / social problems - avoiding company, irritability, loss of libido, feeling emotionally 'numb'
• lethargy - too tired to cope, everything an effort
• physical symptoms - often joint pain or stomach problems, lowered resistance to infection
• behavioral problems - especially in young people

as part of their nature, for whom the occurrence of these problems is still seasonal, is constantly declining, so that what began as "seasonal affective disorder" has long lost both, its restriction to "affect" and its "season-"ality. A phenomenon, by the way, which should hardly surprise us. After all, we have done our very best to get rid of all kinds of all the inconvenient and unproductive seasonality in our lives, so that cynics would probable argue, that we are now paying the price for the 24/7 + 365-days-a-year availability of everything... 

From seasonal affective to circadian affective and physiological disorders

Before we are digressing any further into philosophical consideration, let's take a more scientific 2nd look at the enlightening (all puns intended) connection between the "winter blues", obviously a matter of circannual rhythmicity, and its high(er)-frequency equivalent the 'daily affective disorder'.

Figure 1: Circadian and circannual rhythm are both influenced by the sunlight and insufficient light exposure in the "high in intensity light hours" of the summer days can have the same detrimental effects on your psychological and physiological well-being as the dreaded "winter blues" aka "seasonal effective disorders" - no wonder they also respond to the same treatment strategies, i.e. dawn simulations and / or bright light therapy (respective data from Terman. 2006.)

The collage of data and illustrations I have come up with in figure 1 should actually make it pretty obvious: Despite the fact that the term 'circadian affective and physiological disorders' I have already used in the caption of this paragraph does not exist, the symptoms by which it makes itself felt, the sleep problems, the ravenousness, the depressive undertone, the lethargy, the tiredness, etc. are virtually identical.

Figure 2: Illustration of normal circadian rhythmicity (green), in seasonal affective disorders (SAD, red) and a circadian mismatch due to a phase-shift (violet); the units are more or less arbitrary.

In the end, you could probably argue that "SAD" is nothing but the "natural" accumulation of a light debt and results in a similar suppression of the natural amplitude (= degree of ups and downs, figure 2, green) of the circadian rhythm as a mismatch of the internal clock with external time emitters, above all the light of the sun.

How to "hack" your circadian rhythm

Despite the fact that the outcome of seasonal depressive disorders, on the one hand, and the downstream effects of permanent "social jet lag", or other misalignments of your biological clock and the "social time" you are living in, on the other hand, are in fact almost identical, the classic "winter blues" is the result of simple light deprivation, while the more complex pattern of circadian disorders has an intensity and a phase component and will necessarily have to be fixed differently.

What chronotype am I? Find out and become a part of a scientific study! While it is unquestionably possible to come up with an indefinite number of "classes" between the classic "early bird" (=person who raises with or before sun rise) and the "owl" (=person who rises, when the birds are having lunch), the scientific branch of chronotyping, which is occupied with the study of human rhythms in behavioral and cognitive functions, has come up with (you guessed it) a standardized questionnaire, the "Munich Chronotype Questionnaire", you can fill out here and will receive a "personal profil" via email.

Figure 4: Suggested starting times for 10,000-lux 30-minute session; timepoint is ~8.5h after the estimated melatonin onset (Termann. 2005)

If you don't want to wait or don't trust the German researchers, you can also download the modified Horne-Östberg Questionnaire, here. When you've filled it out, you will be able to calculate your "Morningness Eveningness Score." Based on that score you can then locate your suggested starting time in figure 4. The respective recommendations are based on a paper by Terman from 2005 and have been developed for SAD, so take them as what they are guidelines, not rules!

While research suggests that the correct timing of light exposure/therapy is of little or no importance as far as its beneficial effects on depression scores are concerned (Wirz-Justice. 1993), the so-called "circadian phase-delay", as scientists refer to the "time-shift" between natural and social clock (see figure 2, violet), must not be ignored if you intend to realign or protect yourself from future misalignment of your social and biological time domains.

The situation in figure 2 (violet), for example, depicts a ~4h phase shift, which would get you up and out of bed with the dreaded "2-AM wake-up call" (by the way pretty common in people who overtrain), 4h before your time!  

Now what can you do to battle this problem? Get out of bed switch on your 10,000 lux light therapy lamp, log on to facebook, check a couple of emails and sip a strong coffee? If you want to and can afford to be back to bed at 6 PM, go for it. If you don't you better stay in bed (and in the dark!), get up as you would "like" to and take a 30min "light shower" 1-2h after the time your morningness-eveningness score   would dictate (see infobox "What chronotype am I?") This will help you to push the onset of melatonin release gradually backwards until you reach the point, where it is ~8.5h before your "optimal" or necessary wake-up time.

For someone with an MEQ score of 45 who would ideally get up at 7 AM but won't make it to the office in time if he isn't up at least 1h "before his current time", on the other hand, a different strategy would be necessary.

Instead of turning around and sleeping the day away, he would set the alarm clock ahead by about 1h, jump out of bed at 5:00 AM, get his 30 min of bright light therapy in front of his 10,000 Lux lamp and do his regular morning routine afterwards. As soon as it becomes easier to get out of bed, it's time to set the alarm clock to 5:30 AM and eventually to 6:00AM.

It should be obvious, that even that will never be optimal for someone who is a born owl, i.e. a person whose genetic clock is set to wake him up, when the rest of the world has just had lunch. The daily and most importantly regular, early and intense light exposure in the morning is  going to help him to get out of bed easier and it will also increase his chances that the earlier onset of melatonin production combined with the tricks I have outlined in the last installment of this series allow him to fall asleep in time and get his 7-9h of sleep before the next light therapy session.

Warning: Guidelines and examples are no blueprints! These examples, as well as the figures in the infobox on chronotypes are very broad recommendations! You won't be able to avoid experimenting in order to pinpoint the optimal regimen for you.

Ok, I am convinced, what device shall I get?

What's that Valkee device? Is that any good? While there is a sponsored study on the efficiacy of the Valkee bright light device a "plug in your ear" light therapy device, the study is uncontrolled, which renders is more or less impossible to say how much of the observed beneficial effect the scientists measured by two different tests (HAMD-17 & BDI-21) were simply the result of a placebo effect (Timonen. 2012).

Figure 3: Comparison of BDI improvements of the Valkee device and classic light therapy (based on Timonen. 2012 and Meesters. 1993, respectively)

This does not mean that this device does not work, it just means that light therapy through the eyes is a well-established method not just to treat depressive disorders, but also to reprogram your circadian rhythm. The Valkee, on the other hand, could be a mobile and thus very convenient alternative (or adjunct) to the classic devices. It does yet still lack credible independent research that would prove its effectiveness - something like the 1993(!) study by Meesters et al. I picked as a comparison and in which only 4 days of light therapy with a classic 10,000 lux lamp had slightly more pronounced effects than the Valkee, even 10 days after the therapy had ended (see figure 3; note: It must be said that this is at best a binary comparison, because a quantitative comparison of the study outcomes from these studies can would at best serve as a basis for a hypothesis that would then have to be verified in a future trial).

The information we have compiled in the just mentioned last installment of this series does also come very handy, when you are clicking through the various product descriptions that will turn up when you enter the search token "light therapy lamp" into your favorite product search engine. Basically there are two different systems you can use if you want to try to "hack" (I know that this term is ludicrous, but I'll use it anyway, 'cause its also fashionable and would boost the sales if I ever intended to make an ebook out of this text ;-):

• a 10,000 lux full natural daylight spectrum white energy lamp or light therapy device, which will provide the full natural spectrum (you remember that's the sum of all frequency components of the sunlight, see  figure 2 in the last installment) without the potentially carcinogenic UV part - I don't have to tell you that this implies that you won't get tanned, right?
• a blue light that produces a light that has the same spectral composition as the blue sky on a summer day and is likewise devoid of the invisible high frequency ultraviolet part of the spectrum

According to the claims of the producers of such devices the blue light allows for shorter exposure times to achieve the desired effects.

This assumption does unquestionably seem reasonable, but the same is true for the hilarious notion that eating more protein will make you gain proportionally more muscle or that the presence of cholesterol in arterial plaque would verify that cholesterol is the cause of heart disease. Independent and controlled large(r) scale trials to support these claims are yet scarce and in the case of an even more innovative device, the fancy Valkee "brain stimulation set" that's supposed to shine light through your ears onto the recently discovered light sensitive proteins in your brain (for more info on the Valkee, check out the infobox on the right and the website of the producer), simply non-existent.

I personally did therefore decide to buy a classic white energy light system, also in view of the fact that you can simply place it right next to you at the breakfast table, the newspaper, your computer screen or wherever you want during your morning "circadian rhythm hacking sessions" *rofl* - this is by the way I use my device - at least if the weather / season / my wake-up time doesn't allow me to use the sun instead; and believe me, the blue light or Valkee could hardly be more convenient.

Side effects, summary & guide:

Bright light therapy guide

Intensity & wavelength requirements For white light pick a device that emits the full-spectrum of the visible light at 10,000 lux (measured at the level of the eyes of the user!)

Distance from light source Remain positioned at approximately 20–60 cm from the light source; don't stare directly into the light, the lamp just has to be in your field of view

Time of day for application In 90% of the cases the morning is the best time to apply light therapy; different rules do apply if you have to adapt your biological clock to a totally unnatural social rhythm, as it would for example be the case if you work night-shifts.

Dose 30 min at 10,000 lux, more does not necessarily help more, if you feel sleepy too early rather implement a second sitting

Onset of effect and maintenance 3–7 days till the effect sets in; if you use it to enforce an unnatural rhythm the effect will probably vanish shortly after discontinuation of therapy

In case of non-response double-dose, if you feel sleepy before your time; start earlier or add melatonin (3-10mg) before bed, if you can't get to bed in time.

In the end, it is still up to you, which device you want to buy. The guidelines in the overview on the right, which is based will probably work for the blue light systems and the Valkee, as well (assuming that those do work ;-). It is yet still by no means sure if and to which extend you can benefit and there are even occasional reports of allegedly mostly transient side effects, such as...

• hyperactivation and/or difficulty to fall asleep, which is by the way not just restricted to cases in which you apply the light too late in the day
• light headaches and/or nausea, which are particularly likely to occur in the transition periods or can be a simple consequence of starting starting out with a too hefty (=long) dose
• visual side effects, which are usually a result of staring into the light, which is not necessary for the light therapy to work, so don't do it

Other than that, Terman & Terman mention in a 2005 review paper that in their trials on patients with all sorts of serious psychological disorders, like manic depression or bipolar disorders, it was often necessary to increase the dosages, both time- and intensity-wise slowly to avoid flare-ups of these pre-existing problems. Compared to your average energy drink, let alone pill, the 30-min in front of a light therapy lamp are yet still child's play... its effects on the other hand are longer lasting and way more far-reaching.

A sneak peak on the next installment: In the next installment of the Circadian Rhythm Series we are going to leave the light out, only literally, of course, and devote ourselves to such profane things as food, what your biological clock tells you about when and what to eat and which effects this can have on your physique, performance and overall health.

References:

• Baroni BM, Leal Junior EC, Geremia JM, Diefenthaeler F, Vaz MA. Effect of light-emitting diodes therapy (LEDT) on knee extensor muscle fatigue. Photomed Laser Surg. 2010 Oct;28(5):653-8. Epub 2010 Jul 13.
• Blouin AG, Blouin JH, Iversen H, et al. Light therapy in bulimia nervosa: a double-blind, placebo controlled study. Psychiatry Res. 1996;60:1 9.
• Braun D, Sunday S, Fornari V, Halmi K. Bright light therapy decreases winter binge frequency in women with bulimia nervosa: a double-blind, placebo controlled study. Compr Psychiatry. 1999; 40:442-8.
• Howland RH. An overview of seasonal affective disorder and its treatment options. Phys Sportsmed. 2009 Dec;37(4):104-15.
• Lam RW, Goldner EM, Soplyom L, Remick RA. A controlled study of light therapy for bulimia nervosa. Am J Psychiatry. 1994;151: 744-9.
• Meesters Y, Jansen JH, Beersma DG, Bouhuys AL, van den Hoofdakker RH. Light therapy for seasonal affective disorder. The effects of timing. Br J Psychiatry. 1995 May;166(5):607-12. 
• Reiter RJ, Rosales-Corral S, Coto-Montes A, Boga JA, Tan DX, Davis JM, Konturek PC, Konturek SJ, Brzozowski T. The photoperiod, circadian regulation and chronodisruption: the requisite interplay between the suprachiasmatic nuclei and the pineal and gut melatonin. J Physiol Pharmacol. 2011 Jun;62(3):269-74.
• Terman M, Terman JS. Light therapy. In: Kryger MH, Roth T,  Dement WC, eds. Principles and Practice of Sleep Medicine. 4th  ed. Philadelphia, Penn: Elsevier; 2005:1424-1442. 
• Terman M, Terman JS. Controlled Trial of Naturalistic Dawn Simulation and Negative Air Ionization for Seasonal Affective Disorder. Am J Psychiatry. 2006; 163:12.
• Timonen M, Nissilä J, Liettu A, Jokelainen J, Jurvelin H, Aunio A, Räsänen P, Takala T. Can transcranial brain-targeted bright light treatment via ear canals be effective in relieving symptoms in seasonal affective disorder? A pilot study. Med Hypotheses. 2012 Apr;78(4):511-5.
• Wirz-Justice A, Graw P, Kräuchi K, Gisin B, Jochum A, Arendt J, Fisch HU, Buddeberg C, Pöldinger W. Light therapy in seasonal affective disorder is independent of time of day or circadian phase. Arch Gen Psychiatry. 1993 Dec;50(12):929-37. 

Wake-Up Light as Natural Ergogenic: Dawn Simulation Increases Early Morning Physical & Cognitive Performance

What could be better than starting your day with the first rays of the sun? Doing this with a person you love, I suppose.

If you have listened to Super Human Radio earlier this week (download episode), you will have heard that Carl "caught" me off guard calling me without prior notice during the live show. We ended up talking about the use of melatonin and my beloved "daylight lamp" (light therapy lamp), which kept my energy levels up even at the darkest winter mornings over the past couple of months.

If you listened to the show, you may also remember that Carl mentioned that it would be great to have a light-based alarm clock - something like a light therapy lamp that increases its intensity gradually at a given time and will thus wake you up from a deep slumber.

You can learn more about sleep and the circadian rhythm at the SuppVersity

Sunlight, Bluelight, Backlight and Your Clock

Sunlight a La Carte: "Hack" Your Rhythm

Breaking the Fast to Synchronize the Clock

Fasting (Re-)Sets the Peripheral Clock

Vitamin A & Caffeine Set the Clock

Pre-Workout Supps Could Ruin Your Sleep

Well, I already mentioned during the show that a corresponding device is already available, but pretty useless for someone who usually uses blindfolds to get a good night's sleep. For the rest of you, who are sleeping in a pitch black room without covering their eyes with a blindfold, on the other hand, Carl's suggestion could be a viable means to "improve both cognitive and physical performance after waking." (Thompson. 2014).

This is at least what a recent study from the University College London would suggest. For the corresponding experiment, the researchers from the Department of Epidemiology and Public Health recruited 8 young adults (four males; four females) with a mean age of 24 ± 9 years who had not been involved in nocturnal shift work or undertaken transmeridian travel during the past 30 days (that's important to ensure that their circadian rhythm was not messed up in the first place).

Dawn Simulation? How did that work? Two dawn simulation devices (Lumie Bodyclock Active 250) were placed at either side of the participants’ bed at a distance of 30 cm to ensure they were exposed to the light. thirty minutes prior to waking, dawn simulation was initiated, starting at 0.001 lux and rising to 300 lux following a sigmoidal illumination ramp. Accuracy was confirmed by measurement of illuminance with a digital photometer.

The trials themselves were ordered in a counterbalanced fashion and were separated by 5–9 days. In the two days leading up to the tests, the participants were asked to sleep the exact times in their own homes that they would in the laboratory. to monitor compliance wrist accelerometers were issued.

Did you know that previous studies support the use of dawn simulations to tread seasonal effective disorder, where it was on top of that associated with lower remission rates than regular light therapy (Avery. 1993 & 2001). In addition, dawn simulations have been shown to have beneficial effects on the necessary and natural and healthy (Clow. 2010) early morning increase in cortisol (Thorn. 2004)?

"The experimental trials were identical with the exception of the 30 min prior to waking. During this time par ticipants either slept normally in complete darkness, the control condition (c), or were exposed to dawn simulation (DS).

Each night’s sleep ended with an audible alarm. At the same moment, a researcher entered the room to ensure that the participant was awake. Participants were then allowed to attend the bathroom if required.

After waking, a 75 min testing protocol commenced which consisted of: three bouts of cognitive assessment, one physical performance test and monitoring of physiological and subjective variables." (Thompson. 2014)

In view of the fact that I already gave away the results, it's probably not really surprising that the data in Figure 1 confirms that being waken up by artificial sunlight had significant beneficial effects on the cognitive and physical performance of the subjects.

Figure 1: Changes in number of total additions and reaction time in cognitive tests (Thompson. 2014)

What did not differ, though, were the sleep efficiency, sleep latency, and the total sleep time. In a similar vein, the differences in perceived sleepiness and body temperature were visible, but not statistically significant.

The Philips Wake Up Light, I mentioned on the air has a similar 300lux daylight lamp as the device used in the study at hand.

Bottom line: Overall my good friend Carl Lenore was thus (once again) right. Emulating the Sun's "natural" wake-up call will get your body and mind going in the morning. The fact that this worked with only 300 lux and eventually being woken up by the usual nasty alarm clock is telling me that it may be worth checking what happens if you ditch the alarm clock altogether and increase the light intensity from 0 to 10,000 lux so that the light and not the alarm clock wakes you up.

Whether this or the addition of a "post-wake-up" session in front of a light therapy lamp, as the one I use, provides additional benefits, would yet have to be verified in a controlled trial.

References:

• Avery, David H., et al. "Dawn simulation treatment of winter depression: a controlled study." American Journal of Psychiatry 150 (1993): 113-113.
• Avery, David H., et al. "Dawn simulation and bright light in the treatment of SAD: a controlled study." Biological psychiatry 50.3 (2001): 205-216.
• Clow, Angela, et al. "The cortisol awakening response: more than a measure of HPA axis function." Neuroscience & Biobehavioral Reviews 35.1 (2010): 97-103.
• Thompson, Andrew, et al. "Effects of dawn simulation on markers of sleep inertia and post-waking performance in humans." European journal of applied physiology (2014): 1-8.
• Thorn, Lisa, et al. "The effect of dawn simulation on the cortisol response to awakening in healthy participants." Psychoneuroendocrinology 29.7 (2004): 925-930.

Let There Be Light: 10 New Studies to Enlighten You About the Health Effects of Light Exposure on Health & Physique

No, the sun does not kill you. If you control your exposure it may extend your life and improve your life-quality significantly.

It's about time to "let there be light" to illuminate the benefits of regular well-timed exposure to sunlight and it's short frequency component. Only recently, researchers from the Japanese National Institute of Advanced Industrial Science and Technology (AIST) were able to show that daytime light exposure has significant beneficial effects on cognitive brain activity. Significant enough to have the subjects perform better on an oddball task and to significantly increase cortical activity related to cognitive processes (Okamoto. 2014).

But is that really all, bright light, or more specifically, the regular and well-timed exposure to bright light can do for you?

The effects on circadian rhythm could be behind the Sun's anti-cancer effects

Sunlight, Bluelight, Backlight and Your Clock

Sunlight a La Carte: "Hack" Your Rhythm

Breaking the Fast to Synchronize the Clock

Fasting (Re-)Sets the Peripheral Clock

Vitamin A & Caffeine Set the Clock

Pre-Workout Supps Could Ruin Your Sleep

Certainly not. I mean if it's ill-timed, like the evening use of light-emitting eReaders it will negatively affect your sleep, mess up your circadian rhythm and decrease your alertness on the next morning. Similar results, i.e. drowsiness and suppression of energy metabolism the following morning, have been reported by other studies, as well (Kayaba. 2014).

As a SuppVersity reader you do yet know all about those negative effects from the circadian rhythm series, anyway. Reason enough for me, to focus primarily on all the good stuff, the well-timed exposure to bright light can do for you in today's Special of the SuppVersity Short News.

• If you can't let go off your mobile at night, use blue blocker glasses as a countermeasure for alerting effects of evening light-emitting diode screen exposure - According to researchers from the Psychiatric Hospital of the University of Basel, blue blocker glasses (BB) significantly attenuate LED-induced melatonin suppression in the evening and decrease vigilant attention and subjective alertness before bedtime.
  
  Strangely, though, visually scored sleep stages and behavioral measures collected the morning after were not modified. Still, van der Lely et al. conclude: "BB glasses may be useful in adolescents as a countermeasure for alerting effects induced by light exposure through LED screens and therefore potentially impede the negative effects modern lighting imposes on circadian physiology in the evening "(van der Lely. 2014).
• UV-light protects against "brainflammation" in MS model - Scientists from the University of Wisconsin-Madison report in their latest paper that UV light selectively inhibits spinal cord inflammation and demyelination in experimental autoimmune encephalomyelitis.
  
  Previous studies have already shown that UV radiation (UVR) can suppress experimental autoimmune encephalomyelitis (EAE), an animal model of multiple-sclerosis (MS), independent of vitamin D production. The mechanism of this suppression did yet remain to be elucidated, until Wang et al. (2014) observed that UVR (10kJ/m²) does not just inhibit the inflammation and demyelination of the spinal cord, but will also dramatically and significantly reduce spinal cord chemokine CCL5 mRNA and protein levels.
  
  In conjunction with an increased production of intereron-gamma (IFN-γ) and IL-10, which are actually used to treat all sorts of autoimmune diseases, artificial and natural UV light can thus actually "prevent the migration of inflammatory cells into the CNS" (Wang. 2014).

• 

  Melatonin conc. after 4 days w/ dim vs. bright light and tryptophan rich vs. poor breakfast (Fukushige. 2014).

  Bright light in the AM and the consumption of a breakfast that's high in tryptophan can help you maintain a healthy circadian rhythm - In case you are asking yourself how you can grasp all the benefits that are associated with having an intact circadian rhythm, you may be intrigued to hear that researchers from the Fukuoka Women's University have been able to show that an increase in tryptophan intake at breakfast combined with daytime light exposure has beneficial effects on melatonin secretion and sleep quality. As you can see in the figure to the left it will significantly elevate the evening melatonin peak, which is critical for an optimal circadian rhythm.
  
  If you are looking to optimize your internal clock bright light (either sunlight or a 10,000 Lux daylight lamp) + tryptophan (seeds, nuts, soy, cheese, chicken, turkey, fish, oats, beans and eggs are the TOP10 sources) are the way to go. If you want an extra "kick" add some coffee to the equation. This will increase the light responsiveness of the circadian pacemaker - well, at least in mice it does (Diepen. 2014).

If you want to design your own "dawn simulator" that's the spectrum you need (Virginie. 2014).

Wanna be smarter, but can't get enough sleep? Start your day with a dawn simulation: Chronic sleep restriction (SR) has deleterious effects on cognitive performance that can be counteracted by light exposure. Scientists from the Psychiatric Hospital of the University of Basel have recently been able tho show that a dawn simulating in the AM will increase your task performance throughout the day after morning; and what's best: The benefit was most pronounced in those participants who sucked the most when they didn't get a good night's sleep (Virginie. 2014).

• Bright lights at work will keep you sane, happy and alert - If you are working in an insufficiently lit office without natural sunlight, you should be prepared to develop physiological, sleep and depressive symptoms.
  
  Assuming you have a window in your office, you will get a significantly more pronounced total and peak exposure to bright light that's going to correlate with 33% reduced levels of the stress hormone cortisol, a more natural rhythm of melatonin and a reduced risk of minor psychiatric disorders and depressive symptoms (MA) in the evening.
  
  That's at least what the results of a recent study from the UFRGS in Porto Alegre indicates (Harb. 2014). A study the authors of which proudly say that their "study demonstrated that not only may light pollution affect human physiology but also lack of exposure to natural light is related to high levels of cortisol and lower levels of melatonin at night, and these, in turn, are related to depressive symptoms and poor quality of sleep" (Harb. 2014).

• 

  If you want to light up the darkness, when it's actually time to sleep do it with green (555nm) or red, not blue light, which suppresses melatonin (Bonmati-Carrion. 2014).

  Staying away from nightly night exposure may also help to keep your arteries clean even in the old age - Studies indicate that even after  adjustment for confounding factors, including age, gender, body mass index, current smoking status, hypertension, diabetes, dyslipidemia, sleep medication, estimated glomerular filtration rate, nocturia, bedtime, duration in bed (scotoperiod), day length (photoperiod), urinary 6-sulfatoxymelatonin excretion and daytime and nighttime physical activity, exposure to light at night is associated with carotid intima-media thickness (Obayashi. 2014).
  
  If you don't want to develop subclinical carotid atherosclerosis, when you are old, it would thus be a good idea to adhere to the basic rules of sleep hygiene: a dark room and/or blindfolds will keep your arteries clean and may thus save your life ;-)
• If you have kidney problems, get out in the sun if you want to survive - Scientists from the University of California Irvine Medical Center were able to show that dialysis patients residing in higher UV index regions have lower all-cause mortality compared to those living in moderate-high UV regions (Shapiro. 2014).
  
  More specifically, the ~60year-old subjects residing in moderate-high UV index regions had a 16% reduced risk of all-cause mortality. Those living in very-high UV index regions had a 1% higher risk reduction (17%). Interestingly, there was a similar inverse association between UV index and mortality was observed across all subgroups, but it was more pronounced among whites vs. non-whites.
• Wear those shades (or bluelight blocker glasses) before any important sport event - Why? Stupid question. If you dabble around with your smartphone "unprotected" the evening before an important sport event for only 30 minutes, this can influence exercise performance under hot conditions during the subsequent early morning (Thompson. 2014).

Even brief light exposure, when your eyes are closed messes with your circadian rhythm.

Pah, when your eyes are closed, light is not a problem, right? Wrong. Even ,illisecond flashes of light phase delay the human circadian clock during sleep. While a greater number of matched subjects and more research will be necessary to ascertain whether these light flashes affect sleep, data from a recent study from the California Mental Illness Research Education and Clinical Center suggest that 2-msec light flashes given every 30 sec have an effect on the circadian rhythm of healthy volunteers. And while Zeitzer et al. (2014) tried to use the flashes to modify the rhythm in a beneficial way, the exact opposite can also be the case. It all depends on how / when you are exposed to light when you sleep.

Sleep disturbance and adaptive immunity. Following a night of sleep loss, or during a period of sleep disturbance, nerve fibers from the sympathetic nervous system (SNS) release the neurotransmitter norepinephrine into primary and secondary lymphoid organs and stimulate the adrenal gland to release stored epinephrine into systemic circulation. Both neuromediators stimulate leukocyte adrenergic receptors (e.g., ADRB2) and activate nuclear factor (NF)-κB-mediated inflammatory programs (Irwin. 2015).

• If your grandparent's have Alzheimer's install a timer-based light system - This may not just increase their sleep quality, but it will also improve their behavior and mood as indicated by reduced depression scores on the Cornell Scale for Depression in Dementia and agitation scores from the Cohen-Mansfield Agitation Inventory (Figueiro. 2014).
  
  I must warn you, though: The recent field study from the Rensselaer Polytechnic Institute is promising, but the results should be replicated using a larger sample size and perhaps using longer treatment duration.
• If you have to work night shifts consider using 1-5mg melatonin 1h before you go to bed - Why? You have to counter the natural decline in melatonin production that occurs over consecutive days of night work (Dumont. 2014).
  
  In a recent study from the Sacre-Coeur Hospital of Montreal the melatonin production of the healthy volunteers decreased progressively decreased over consecutive days of simulated night work, both during nighttime and over the 24 h. Interestingly, this decrease was larger in women using oral contraceptives and independent of bright light exposure.
• Get out into the sun and cure your back pain - If your back hurts and neither you or your doctor have a clue why, try getting into the sun. A study from the UMIT in Austria shows that only three sessions in front of 5.000 lx lamp improved the depressive symptoms and reduced the pain intensity in CNBP adults with chronic nonspecific back pain (Leichtfried. 2014).

One of the side effects of blue light LED exposure (open circles) in the PM is a sign., but practically prob. irrelevant reduction in energy exp. on the next morning (Kayaba. 2014).

Bottom line: I really hope that I do not have to sum up the results for you. I mean, it should be obvious that sleep hygiene at night and light exposure at day are among the most important factors of the lifestyle-factors in the exercise + nutriton + lifestyle solution to perfect health & obesity protection (Partonen. 2014).

Against that background I would like to use the last lines to put another emphasis on the results of the recent study by Kayaba et al. (2014) which found that one of the negative consequences smartphone junkies have to suffer on the morning after using their devices before bed is a reduction in energy expenditure.

If you take a look at the data in the figure at the right (open circles = exposed; full circles = non-exposed), you will yet realize that this probably isn't the worst side effect of blue-LED light exposure in the evening. The reduction is significant in the AM, yes, but on its own it's not practically relevant | Comment on Facebook!

References:

• Bonmati-Carrion, Maria Angeles, et al. "Protecting the Melatonin Rhythm through Circadian Healthy Light Exposure." International Journal of Molecular Sciences 15.12 (2014): 23448-23500.
• Diepen, Hester C., et al. "Caffeine increases light responsiveness of the mouse circadian pacemaker." European Journal of Neuroscience 40.10 (2014): 3504-3511.
• Dumont, Marie, and Jean Paquet. "Progressive decrease of melatonin production over consecutive days of simulated night work." Chronobiology international 0 (2014): 1-8.
• Figueiro, Mariana G., et al. "Tailored lighting intervention improves measures of sleep, depression, and agitation in persons with Alzheimer’s disease and related dementia living in long-term care facilities." Clinical interventions in aging 9 (2014): 1527.
• Fukushige, Haruna, et al. "Effects of tryptophan-rich breakfast and light exposure during the daytime on melatonin secretion at night." breast cancer 4 (2014): 9.
• Harb, Francine, Maria Paz Hidalgo, and Betina Martau. "Lack of exposure to natural light in the workspace is associated with physiological, sleep and depressive symptoms." Chronobiology international 0 (2014): 1-8. 
• Irwin Michael, R. "Why Sleep Is Important for Health: A Psychoneuroimmunology Perspective." Annual Review of Psychology 66 (2015): 143-172.
• Kayaba, Momoko, et al. "The effect of nocturnal blue light exposure from light-emitting diodes on wakefulness and energy metabolism the following morning." Environmental health and preventive medicine 19.5 (2014): 354-361. 
• Leichtfried, Veronika, et al. "Short‐Term Effects of Bright Light Therapy in Adults with Chronic Nonspecific Back Pain: A Randomized Controlled Trial." Pain Medicine 15.12 (2014): 2003-2012.
• Obayashi, Kenji, Keigo Saeki, and Norio Kurumatani. "Light exposure at night is associated with subclinical carotid atherosclerosis in the general elderly population: The HEIJO-KYO cohort." Chronobiology international 0 (2014): 1-8.
• Okamoto, Yosuke, and Seiji Nakagawa. "Effects of daytime light exposure on cognitive brain activity as measured by the ERP P300." Physiology & behavior 138 (2015): 313-318.
• Partonen, Timo. "Obesity= physical activity+ dietary intake+ sleep stages+ light exposure." Annals of medicine 46.5 (2014): 245-246.
• Shapiro, Bryan B., et al. "The Relationship Between Ultraviolet Light Exposure and Mortality in Dialysis Patients." American journal of nephrology 40.3 (2014): 224-232. 
• Thompson, A., et al. "The Effects of Evening Bright Light Exposure on Subsequent Morning Exercise Performance." International journal of sports medicine EFirst (2014).
• van der Lely, Stéphanie, et al. "Blue blocker glasses as a countermeasure for alerting effects of evening light-emitting diode screen exposure in male teenagers." Journal of Adolescent Health (2014).
• Virginie, Gabel, et al. "Dawn simulation light impacts on different cognitive domains under sleep restriction." Behavioural Brain Research (2014).
• Wang, et al. "UV light selectively inhibits spinal cord inflammation and demyelination in experimental autoimmune encephalomyelitis." Arch Biochem Biophys. (2014). [Epub ahead of print]
• Zeitzer, Jamie M., et al. "Millisecond Flashes of Light Phase Delay the Human Circadian Clock during Sleep." Journal of biological rhythms (2014): 0748730414546532.