80g Glycerol + 2L Water Decreases Body Weight in Athletes & Increases Overall Performance in Sedentary Subjects

If it does not make you as swole as the colorful ad promised it must not be working, right? The jury was not even any longer "out there" for glycerol, but a recent study makes you rethink, whether you just have to look in the right place to see the benefits.

Another of the "odd" Thursdays without an update from "Your's Truly" Adelfo Cerame. And since there is holiday today, over here, I even thought there would not be a SuppVersity Science Round Up today. But hey, you are lucky you (and Carl) got to work, so you can tune in live at 1PM EST, or even better, start listening live at 1PM in order not to miss the Strength and Hypertrophy Round Table!

As far the  topics for today's installment of the SuppVersity Science Round Up are concerned, you are actually only a couple of lines away from reading about one that's on the list:  The effects of glycerol on exercise performance. I don't have to tell you though that this is not everything. Other things I believe you may be interested in are...

• childhood obesity, physical education and attention at school
• wheat gluten hydrolysate and how they don't come up to the expectations early trials have raised
• ammonia accumulation brain-fog, toxicity, liver 'pathologies' and workout performance
• running next to a street entails 'particular downsides' ("particular" is to be taken literally, here ;-)
• homocysteine levels, mortality, cognitive impairment and more
• epigenetic programming by nicotine and different protein contents before birth

These topics alone obviously won't fit into a single episode, but by now you should be aware that the SuppVersity Science Round Up Seconds, which are always published one day after the show aired, will provide you with the things we have missed and additional information, suggested reads and graphs to the topics we covered...  apropos "won't fit in", since the above is not even everything I have up my sleeve, I thought it would be wise to take the glycerol news from the compilation and tackle it on its own, today.

Can the backbone of bad triglycerides really be good for you?

Glycerol, a 3-carbon sugar alcohol that provides the backbone of triglycerides and is naturally found in foods as a component of dietary fats (Burke. 2011), is one of those supplements that have been all the rage for some time, didn't produce the expected instant results everybody was looking for (in this particlar case mostly "skinbursting pumps" and have eventually, in the course of one or two cycles of the regular yearly reformulations of the pre-workout supplements, completely disappeared from the market. I was therefore surprised, when I hit onto a recent study by researchers from the Physical Education and Sport High School in Konya (Turkey) that was published in one of the latest issues of the Journal of Human Kinetics (Patlar. 2012).

Is glycerol save? There have not been any reported toxicity effects up to doses of 5g/kg body weight. Glycerol does accumulates in body fluids, with the exception of the brain and the eyes and increases osmotic pressure (which was the reason why people used it in "pump supplements"), as well as the total volume of water in the body. If anything was 'dangerous', or I should probably rather say 'detrimental' to it, it would probably be its energy content (it is subject to gluconeogensis in the liver), which puts you at 'danger' of adding one or another pound of body fat you would probably want to avoid. The results of the study at hand to yet suggest that this is not an issue as long as you are active.

In essence the study protocol is nothing extraordinary: Take a couple of guys, 40 in this case (age 22.82 ± 1.49 years), and feed and water them using...

• 1.2 g/kg body weight) followed by water (26 ml/kg body weight) to 10 sedentary individuals (GS) and 10 soccer players from the University team
• just plain water to the another 10 sedentary men and 10 soccer players

Conduct a baseline test in the course of which all subjects are familiarized with the exercise equipment, a cycle ergometer (Monark 814-E) and required to perform an...

• Astrand Cycle Ergometer Test and an
  
• Wingate Anaerobic Power Test
  *the videos are don't show the study participants

in a room that is kept at 30°C and a barometrical pressure of 668 mm-Hg. For the next twenty days, have half of the guys (athletic groups E and GE) perform a 20-m shuttle run test every day. And finally perform a second follow up to see and evaluate the individual and joint effects of exercise and glycerol supplementation.

What's a shuttle run? I guess those of you who play soccer or basketball will know similar drills (at least I have been tormented by my trainers with them before in both sports and could imagine they are also among the standard repertoire of football coaches - though I have never played that myself):

Video 1: The shuttle run is every trainer's darling and would actually make a nice conditioning workout to be implemented into your own routine - whatever it may you are training for (note: the video is a random pick from YouTube and has no relation to the study at hand).

"The subjects warmed up for several minutes by jogging followed by stretching. The test program was installed on the computer and  initiated. A single beep was emitted at regular intervals. The subjects had to complete a lap or shuttle (foot on or over the line) with each beep. If the subjects completed a lap early they had to wait for the beep before starting the next lap. A triple beep indicated the start of a new level with a slightly faster speed required to complete each  lap.

The subjects were encouraged to complete as many levels as possible. An observer monitored the progress of a given subject, recording each completed lap on the recorder form. The subjects were instructed to turn by pivoting and not to run in a wide arc. The test was terminated when a subject was two or more steps from the line, for two consecutive laps. The observer alerted the subject at this time." (Patlar. 2012)

The shuttle run was followed by a couple of minutes of walking to cool down and a stretching exercise. The data was collected, logged and archived for evaluation.

Now if we take a look at the results of this undertaking they are unquestionably somewhat surprising - at least at first sight (see figure 1). In absolute terms it looks as if we had an across the board, almost identical increase in performance due to the daily shuttle runs in the exercise groups and a surprisingly large beneficial effect of glycerol only in the sedentary subjects (which would by the way be in line with many of the more or less disappointing trials on the benefits of glycerol supplementation in athletes; cd. Burke. 2011):

Figure 1: Changes in anaerobic and aerobic performance - relative values on the left, absolute before (white) and after (black) on the right (Patlar. 2012)

If you take a look at the relative pre-post changes in figure 1 (left), instead of the absolute changes a more distinct picture emerges:

• the benefit the sedentary subjects derived from the supplementation looks even more pronounced,
• the aerobic performance of the soccer players in the exercise group did likewise benefit, albeit less than the performance of the sedentary group, and
• shockingly the increase in anaerobic performance which looks pretty much identical is not statistically significant, yet still reduced in the glycerol supplemented athletes in the exercise + glycerol group (note: there is an increase, it's only relatively smaller)

Now, we all know that hyperhydration goes hand in hand with an increase in body water. In figure 1 I did even plaster a huge red sticker with "hyperhydration" onto the graph to give you an idea of a possible mechanism of action. So, if we wanted to be fair, we would have to take that into account... what? Yeah and you want to know if it will make you blow up like a wale, right, ... so let's see:

Figure 2: Changes in body weight and relative power (watts per body weight) in the course of the trial (data based on Patlar. 2012)

If we assume you are a sedentary slob at 80kg you could in fact gain 1.6kg... whether that's only water or if there is some fat there, as well, I cannot tell. Notwithstanding, I mentioned in the red box on safety issues, already that you can hardly expect to down 80g of glycerol with an energetic value of 4.32kcal/g (i.e. 350kcal per day) extra everyday without gaining at least some weight (assuming all other parameters are constant; plus, this could be muscle as well - well, not if you don't work out, though ;-).

You cannot expect to lose weight, but surprisingly it may still happen that you do if you consume those 350kcal of glycerol with 2l water right before your daily shuttle run. 

At least this is what happened to the soccer players in the supplementation group: They lost 2.66lbs of body weight on average. "Weight" is the unfortunate key word here, because we have no way of telling whether that was muscle, water or fat weight, as the scientists did not measure that separately. But let's be honest, it appears more than unlikely that it is (a) water or (b) muscle. After all the relative anaerobic power increased equally in both groups and why on earth would you lose water when you hyperhydrate? Ok, it could be one of those counter-regulatory reactions our bodies love. That again should however lead to performance decrements we did not see... you see, it's like the idiomatic dog that's chasing his tail. Why don't you play ginea pig and let us know what happens ;-)

WADA Warning for competitive athletes: If you are a WADA controlled athlete, you better avoid glycerol. It may sound hilarious, but it is on the WADA list of prohibited supplements since 2012. Why? Well, the increase in blood volume could mask the use of testosterone and co. because the /dl count would be lower if the total blood volume is higher -- this is something the WADA officials consider call a "masking agent" (Wada. 2012).

How much do you need? Don't forget, for glycerol to work its hyperhydrating magic, you must consume it with similarly hilarious amounts of water as the subjects in the study at hand. According to van Rosendal et al. an effective protocol comprises 1-1.5 g/kg glycerol + 25–35 ml/kg of fluid. Assuming you weigh 80 kg you can't get way with anything below 80g of glycerol + 2l water! Obviously way more than what any of the hitherto no longer available 'pump' or pre-workout supplements contained (at least I have not come across one that has a 80g scoop and says "consume with at least 2l of water on the label" - have you?)

Bottom line: I want to be honest, I still have to make up my mind about the usefulness of this supplement. I guess what actually does the trick is the combination of hyperhydration + energy availability. I have been preaching more than enough about the importance of energy availability over the last couple weeks, so I don't think I have to go into any more details here.

What I do think, however, is that few of you will be aware of the 2008 paper by Judelson et al. in which they report that hydration status is a fundamental determinant of the endocrine response to exercise, with dehydration leading to inappropriately high cortisol and norepinephrine levels that go hand in hand with an attenuation of the testosterone response to exercise, and negative effects on carbohydrate and lipid metabolism (Judelson. 2008).

Since you should by now have gotten the notion that insufficient energy does exactly the same, glycerol could well provide a means to counter this ergolytic double whammy. Against that background it is however strange that the athletes could not derive any athletic benefit from it... and weight loss without dieting (at least they were advised to stick to their habitual diets)?

If there is one definitive message you can take home from this study, though, it would be related to the dosage advice in the blueish info-box on the top right of this last paragraph: You better know how to use a supplement correctly! And this goes for the manufacturers of supps, as well as for the consumers: While the formers should finally stop putting ingredients into their supps to have them on the label, consumers should learn to identify hilariously underdosed and thus useless 'kitchen sink supplements' that 'have it all', but in doses where 'all' does not produce 'any' effect... how you can do that? Easy: Just make sure you get your daily dose of educative SuppVersity posts every day!

References:

• Burke LM, Stear SJ, Lobb A, Ellison M, Castell LM. A-Z of nutritional supplements: dietary supplements, sports nutrition foods and ergogenic aids for health and performance--Part 19. Br J Sports Med. 2011 Apr;45(5):456-8. 
• Judelson DA, Maresh CM, Yamamoto LM, Farrell MJ, Armstrong LE, Kraemer WJ, Volek JS, Spiering BA, Casa DJ, Anderson JM. Effect of hydration state on resistance exercise-induced endocrine markers of anabolism, catabolism, and metabolism. J Appl Physiol. 2008 Sep;105(3):816-24
• Patlar S, Yalcin H, Boyali E. The Effect of Glycerol Supplements on Aerobic and Anaerobic Performance of Athletes and Sedentary Subjects. Journal of Human Kinetics. 2012; 34: 69-70. 
• Van Rosendal SP, Osborne MA, Fassett RG, Coombes JS. Guidelines for glycerol use in hyperhydration and rehydration associated with exercise. Sports Med. 2010 Feb 1;40(2):113-29.
• World Anti Doping Association. WADA Prohibited List 2010. < http://www.wada-ama.org/Documents/World_Anti-Doping_Program/WADP-Prohibited-list/2012/WADA_Prohibited_List_2012_EN.pdf > retrieved Nov. 01, 2012. 

Is Hydrolized Whey, the New Way to Go? 12 Week Human Study Suggests: Yes, If Your Goal is to Ward Off Oxidative Damage. No, If You Want to Build Muscle & Lose Fat

The typical soccer player is no longer a stick on muscular legs, these days. The sport has changed and so have the physiques of the players.

I guess ever since I published the article "The Glucose Repartioning Effects of Isoleucine: Falsely Underappreciated BCAA and Its Dipeptides Maximize GLUT-4 Expression and Ramp Up Muscular Glucose Uptake" (read it) that discussed the beneficial effect of the small isoleucine peptides in hydrolized whey on glucose metabolism, some of you may have been wondering, whether theh previously sneered at even more insulinogenic fast-digesting, bad-tasting, highly-processed whey protein hydrolysates (WPHs) may not be an alternative, if not the better alternative to whey concentrates or isolates.

Personally, I have always favored the "whole" over its individual parts, but the evidence that there is something special about WPH is accumulating.

"So what kind of new evidence is accumulating here?"

That being said, the latest evidence that would support this notion comes from the Universidade Estadual de Campinas in São Paulo, Brazil (Lollo. 2013). Where Pablo Christiano B. Lollo et al. investigated the effects the provision of whey protein (WP), hydrolysed whey protein (WPH), or a non-protein placebo (maltodextrin, MALTO) would exert on selected biochemical, anthropometric and performance parameters in 24 soccer player over the course of 12 weeks.

The iso-caloric supplements which contained 0.5g of protein (or placebo) per kg of body mass had to be before and after each training session, as well as on rest days (i.e. on Monday). The overall protein intake was relatively low (typical of a sport with a clear endurance focus) and was designed so that the protein of the diet plus that of the supplement would represent 15% of the total daily caloric intake. Both, the diets, as well as the sleep and training schedule were standardized. The intensity and training volume were identical for all individuals having plaing the same position (e.g. striker, defender, etc.). And the amino acid content of the two whey supplements was identical, so that the only difference between the WP and the WPH group was the chain-length of the proteins and peptides in the drinks they ingested.

Figure 1: Changes in markers of exercise induced damage (left) and body composition changes (in %) over the course of the 12-week study period (Lollo. 2013)

As you can see in figure 1 this minute difference was yet enough to result in significantly different responses to the protein supplement in the WPH and WP groups.Only, in the former, i.e. the whey protein hydeolysate group did the scientists observe significant decreases in the muscle damage indicators, creatine kinase (-42%) and lactate dehydrogenase (-30%). The minimal changes in the whey protein group, on the other hand, were not superior to the maltodextrin control.

"The foremost features of this investigation were greater than 40% and 30% decrease in CK and LDH, respectively, obtained after 12 weeks of supplementation with the hydrolysed whey protein. This outcome contrasted even more with the increase of CK, which was approximately  +35% obtained by supplementing with maltodextrin alone." (Lollo. 2013)

As you would expect there were no apparent adverse effects observed in either of the groups whose total total protein intake remained below 2.3 g/kg per day. The renal function and protein metabolism parameters, uric acid and creatinine remained within the physiological limits of normality in all groups. 

WPH the whey for elite athletes? 

In their discussion of the results, Lollo et al. make an interesting point, when they compare their observations to those in previously conducted studies and state:

Right from the archives: "Looking at Fast, Slow & Total Protein Intake. More Than 2g/kg Protein = Madness?" (read more)

"Since studies of the effects of protein supplementation have normally been carried out with non-athlete volunteers in acute experiments (Bolster et al., 2005; Pennings et al., 2011; Tipton & Ferrando, 2008), it was interesting to note that the data collected from elite athletes engaged in a real championship pointed to hydrolysed whey protein being the only form of supplement that effectively diminished the levels of muscle damage biomarkers.

Those results could be understood in light of the high antioxidant capacity of the hydrolysate." (Lollo. 2013)

If that could be confirmed for other elite athletes and highly trained gymrats, as well, the question I raised in the headline of this article may well be answered affirmatively: "Yes, for elite athletes with a high training workload, hydrolized whey proteins may in fact be the better way to go."

If you take a closer look at the data in figure 1 (right hand side), you will have to concede that this could well be a question of the kind of athlete we are looking at. A bodybuilder for example would fare better with regular whey. While soccer training is an allegedly bad model for bodybuilding, the way in which regular whey has the most favorable effects on body composition, i.e. a statistically significant 3.4% increase in muscle mass and non-significant 6% decrease in fat mass, is something I personally would not ignore (on a side note, you did see that the fat loss maxed out and reached statistical significance with the pure maltodextrose, right?). 

---

Metabolic ward study shows: Higher than RDA protein intake turns weight loss into a fat loss diet, yet still it's not the more the better (learn more)

Bottom line: Despite or maybe even due to its high anti-oxidant prowess whey hydrolysate may not be the ideal protein for the average gymrat trying to build muscle, lose fat and improve his overall body composition. Allegedly, a study in soccer players and above all one with only 24 subjects is certainly not a reliable gauge, but why would you quit using what has worked for you before, if the evidence that the alternative may be good, but not exactly conducive to your primary goals?

Moreover, let's not forget, if you are simply trying to pack in some additional protein into your diet, price and taste are certainly things you want to consider, as well. And let's face it the taste and mouth-feel of the few true hydrolysates out there (most supplement producers mix various forms of whey and will still sneak a "hydro" into the name) are not exactly what you would expect from something you'd consume as a "liquid snack", right?

References: 

• Bolster DR, Pikosky MA, Gaine PC, Martin W, Wolfe RR, Tipton KD, Maclean D, Maresh CM, Rodriguez NR. Dietary protein intake impacts human skeletal muscle protein fractional synthetic rates after endurance exercise. Am J Physiol Endocrinol Metab. 2005 Oct;289(4):E678-83.
• Lollo PBC, et al. Hydrolysed whey protein reduces muscle damage markers in Brazilian elite soccer players compared with whey protein and maltodextrin. A twelve-week inchampionship intervention. International Dairy Journal. August 2013 [epub ahead of print]
• Tipton KD, Ferrando AA. Improving muscle mass: response of muscle metabolism to exercise, nutrition and anabolic agents. Essays Biochem. 2008;44:85-98.
• Pennings B, Koopman R, Beelen M, Senden JM, Saris WH, van Loon LJ. Exercising before protein intake allows for greater use of dietary protein-derived amino acids for de novo muscle protein synthesis in both young and elderly men. Am J Clin Nutr. 2011 Feb;93(2):322-31.

New Insights into the Role of Vitamin D in Athletes: Soccer Players Offer Ideal Study Subjects - Vitamin D (25-OHD) Predicts Performance, Training Season Predicts Vitamin D

Not the ideal soccer weather. If you put faith in the authors' interpretation of the results, soccer is a game that must be played in the sun. Why? Well, to maximize the vitamin D production ;-)

It has been a while since I have seen a study on vitamin D that provides new-worthy results beyond the obvious "vitamin D supplements are useless in men and women with normal 25-OHD levels". The study I am about to talk about today was conducted by researchers from the University of Crete. The subjects were sixty seven Caucasian professional male soccer players, members of two Greek Super League Teams (n = 45) and one Football League Team (n = 22). The goal was to (a) examine the potential relationship between vitamin D levels and muscle strength, maximal oxygen consumption (VO2max), 10 and, 20 meters sprint performance in two different occasions, prior to the beginning and at the end of the off-season soccer period; and (b) to examine the vitamin D response to the reduced exercise training during the six-week off-season transition period.

The authors speculated that in both experimental sessions vitamin D levels would correlate with soccer players’ jumping, sprinting, and aerobic capacity, and that the off-season transition period, of reduced training stress, would favorably affect vitamin D concentration.

There are many ways to get your vitamin D learn more the SuppVersity

How Much To Take?

Leucine, Insulin & Vitamin D

Vit. D Speeds Up Recovery

Overlooked D-Sources

Vitamin D For Athletes!

Vitamin D Helps Store Fat

As we are about to see a few lines below, this is exactly what Nikolaos E. Koundourakis and his colleagues found in what is "to the best of [the researchers] knowledge" the first study to examine the relationship "between vitamin D levels and muscle strength, VO2max and speed in professional soccer players, and/or the effects off-season detraining soccer period on its levels in any kind of athletic population." (Koundourakis. 2014)

Table 1: Correlations (correlation coefficients and p-values) between Vitamin D levels and exercise performance parameters; pre = acute pre-season training vs. post = after six-week off-season transition period (Koundourakis. 2014)

As you can see in Table 1, there was a significant correlation between the strength measures squat jump (SJ) and countermovement jump (CMJ), as well as with VO2max and the 10m and 20m sprint times. There was jet also a significant increase in vitamin D from pre to post season, i.e from 34.41 to 47.21ng/ml (37%) of which Koundourakis et al. write the following:

Suggested Read: Leucine, Insulin & Vitamin D: A Hypertrophy Boosting Triplet That Does Not Make It From the Dish to the Gym? | read more

"In our study the six-week transition period had a boosting effect on vitamin D levels. Indeed, at the first experimental period,although none of our participants was vitamin D deficient (<20 ng/ml) or severe deficient (<10 ng/ml), 55,22% of our players had insufficient vitamin D levels (<30 ng/ml), whereas at the second one only 4,47% were found to be below 30 ng/ml. [...] The most plausible explanation for the elevation of vitamin D levels at the second experimental session could be the consequence of an increased exposure to UVB during the off-season period.

Indeed, this transition period in Greek Superleague takes place during June and at the beginning of July at a favorable latitude (35,9°N). During this period UVB reaches its peak, resulting in increased vitamin D production." (Koundourakis. 2014)

These observations highlight the importance of adequate sun exposure and raise the question, whether it wouldn't be prudent to supplement with 2.000IU of vitamin D per day during the winter months to avoid the reduction in vitamin D levels in the first place.

Tanning beds are neither suitable to get your vitamin D levels up (many don't even radiate UV-B light / it's also blocked by glass), tanning on a sunbed is also not safer than doing the same in the sun | more

There is a different explanation: Next to the sun-exposure hypothesis, there is another possible reason for the increase in vitamin D, which would be related to the (albeit beneficial) stress the soccer players are exposed to during each and every of their training sessions. If vitamin D was the negative acute phase reactant, Waldron et al. say it was (2013), it would be logical that the levels increase in the absence of acute stressors.

Needless to say that the latter wouldn't make getting enough UV exposure obsolete - an exposure you better get in the real sun than on one of the allegedly less problematic tanning beds, which lack the vitamin D production kickstarting UV-B radiation.

References:

• Koundourakis, Nikolaos E., et al. "Vitamin D and Exercise Performance in Professional Soccer Players." PLOS ONE 9.7 (2014): e101659.
• Waldron, Jenna Louise, et al. "Vitamin D: a negative acute phase reactant." Journal of clinical pathology (2013): jclinpath-2012.

6mg Melatonin 30min Before HIT Will Increase Fatty Acid Oxidation, Boost Your Antioxidant Capacity, Reduce MDA Levels and Modulate Your Immune Response

Image 1: Other than you may have expected, this is exactly not what happened when the soccer players took 6mg of melatonin before their workouts.

The blogpost on melatonin's anti-Alzheimer's + anti-obesity effects from last week caused quite a stir, both in the comment area, here at the SuppVersity, as well as on facebook. Even friends in the gym came up with questions. Therefore, I suppose that you won't mind, if I re-address the topic today. This time, however, with data from a human study, of which I bet that it will catch your interest... after all, the study, which has been published ahead of print two days before Christmas could hold the key to winning the FIFA World Cup 2014 ;-)

Melatonin makes you sleepy? I don't think so!

I guess, even after last week's news, most of you will still think of melatonin as the "sleep hormone". At least those of you who follow my recommendation to make sure that they get their daily dose of SuppVersity news should yet already be familiar with the notion that melatonin may also be a very effective ergogenic aid / adaptogen to be taken not at night, but right before an event! Contrary to the Ococha study, which, due to its awkward "loading protocol" and the ultra-endurance setting, had little relevance for the average trainee, the recently published study by M.D. Maldanado and his (or her) colleagues (Maldando. 2011) from the Department of Medical Biochemistry and Molecular Biology at the University of Seville Medical School and the Andalusian Centre of Sports Medicine in Spain is approaching an area of physical activity that is much more dear to my heart: Football! Or as you, my American friends would say, "soccer" ;-)

Note: The scientists make a very useful comment with regards to the timing of exogenous melatonin, I guess you will be interested in: "Melatonin itself has a very short half-life in the blood (range of 20–40 min, depending on condition), so that elevated levels cannot persist after many hours. According with concentration-time curve of our laboratory and other researchers, 30-45 min is [sic!] the necessary time so that oral melatonin is absorbed in the gastrointestinal tract (GIT) and can be detected in blood before its metabolism and elimination. On the other hand, considering that melatonin is not toxic and has no undesirable effects, the 6 mg administered assured us their absorption by the mucous and is within the ranges recom- mended for use in humans (3–20 mg)." I hope that will spare me at least a few of the question some of you are probably already harboring ;-)

To study the effects of pre-workout melatonin supplementation on markers of oxidative damage, the Spanish scientists recruited sixteen 18 to 20 year old professional soccer players, and randomized them to receive either placebo or 6mg of melatonin 30 minutes prior to an intense (HR >135bpm; speed 25km/h) 60-min training session on stationary bikes.

Figure 1: Plasma total antioxidant activity (TAS) and lipid oxidation (MDA) before, during and right after 60min of high intensity (heart rate >135bpm) exercise on stationary bike (data adapted from Maldando. 2011)

As you can see in figure 1 the 6mg of melatonin the subjects received immediately before the arduous steady state high intensity "cardio" exercise, did not just ameliorate the -22% (60min mark) decrease in total antioxidant capacity (TAS) in the soccer players, it did in fact raise the TAS levels to +15% over baseline, while the subjects were pedaling on their bikes. Consequently, the increase in lipid oxidation (MDA) levels was profoundly reduced, yet not completely blunted (let alone reversed).

Figure 2: Plasma triglyceride before, during and after 60min HIT training (data adapted from Maldando. 2011)

For those of you who, besides being athletic, also like to look athletic, it may also be of interest that Maldando et al. ascribe the statistically signifant decrease in plasma triglyceride levels in the melatonin group to what they call an increased "catchment and lipids consumption by cells" - and for the native speakers out there - this is the Spanish way of saying that melatonin increases fatty acid oxidation during high intensity steady state exercise and could thusly be highly beneficial for anyone who wants to shed some additional pounds (in addition to what you diet will do for you) on the treadmill, bike or similar "cardio equipment" - and before you ask, I guess this will work for HIIT, as well ;-)

Melatonin increases immune response to 60-min HIT exercise

Its antioxidant and fat-burning activity aside, the 6mg of melatonin eight of the sixteen soccer players consumed before they hopped onto their stationary bikes exerted a statistically significant modulatory effect on plasma IgA levels (ca. +40% after 60min), about which Maldano et al. state that it

[...] indicates the start of a humoral immune response, for which it takes between 5 and 7 days [...so that melatonin] could act to promote the adaptation between plasma and mucosal IgA during the exercise.

Overall, I am becoming more and more convinced that my statement from last week that "melatonin is probably one of the most underrated supplements you can still buy without a script" is actually pretty accurate and that melatonin, as Maldono et al. put it, "could be a plausible therapeutic option for professional athletes that should make major exercises throughout their working lives" ;-)