Caffeine, Exercise and Your Sleep: The Link Could be Sign. Different From What You Expect - Sleep Better W/ Caffeine?

Caffeine, Exercise and Your Sleep: The Link Could be Sign. Different From What You Expect - Sleep Better W/ Caffeine?

caffeine coffee ergogenic exercise health sleep sleep duration sleep quality stimulants

Coffee and exercise both effect sleep, but their effects don't simply add up. The study at hand does yet suggest that your preworkout coffee won't ruin your sleep.

I have to admit, the following are not results of peer-reviewed research, but with a 2x2 week design, participants being randomized to exercise (4 workouts per week) or be sedentary and to consume caffeine or placebo prior to exercise or rest, it looks methodologically complex, but sound and, more importantly, interesting enough to make it into the SuppVersity news ... I mean, it's about coffee ;-)

With that being said, the scientists, who were hopefully less biased than I am, required their subjects to refrain from any extra regular physical activity and or coffee / caffeinated beverage consumption outside of the conditioning/treatment sessions, in which they didn't drink coffee, but 350-mL of Gatorade with or without a rel. low dose of 3mg/kg caffeine.

You can learn more about coffee and caffeine at the SuppVersity

For Caffeine, Timing Matters! 45 Min or More?

Coffee - The Good, Bad & Interesting

Three Cups of Coffee Keep Insulin At Bay

Caffeine's Effect on Testosterone, Estrogen & SHBG

The Coffee³ Ad- vantage: Fat loss, Appetite & Mood

Caffeine Resis- tance - Does It Even Exist?

The authors' data analysis involved the usual mixed analysis of variance with treatment (placebo or caffeine) and condition (exercise or sedentary) as between subjects factors. In addition, time as the repeated measure, and the subjects' usual caffeine intake and BMI were included as covariates.

Figure 1: Mean sleep duration (h) in the different arms / phases of the 2x2 week RCT (O'Brien. 2016).

As the data in Figure 1 tells you, the statistical analysis yielded an independent main effect of
condition (sedentary/exercise) on the number of hours the subjects actually slept (this is not "time spent in bed"). In that, it did matter, whether the subjects worked with or without caffeine, but both, the effects of exercise (SED vs. EX | Figure 1), and as those of caffeine (see PLA vs. CAF | Figure 1) are not exactly what you probably expected:

• Effects of exercise - Subjects who exercised in the lab self-reported less time (hours) sleeping [F(1,18) = 4.5, p = 0.049] compared to sedentary. In that, there was a trend for an independent effect of treatment (placebo/caffeine) on hours slept (p = 0.08),
• Effects of caffeine - Subjects who received placebo self-reported less time (hours) sleeping compared those who received caffeine (that was not what you'd expect based on previous evidence). In that, there were no interactions by usual caffeine intake.

Now, one's sleep duration is only one out of several parameters that will determine whether or not you rise and shine refreshed; plus, since all subjects had average sleep times in the "green zone" of 6.5-8h per night, they were all sleeping enough - irrespective of exercise and/or caffeine. The parameter of actual interest is thus the subjects' subjective sleep quality and its relationship to their perceived tiredness in the AM / over 24h, which were both assessed with questionnaires in the study at hand.

Figure 2: Sleep quality and perceived tiredness over the course of the 2x2 week RCT (O'Brien. 2016).

For the former, i.e. the subjects' sleep quality, the data in Figure 2 signifies that here was a significant time x treatment x condition interaction on overall sleep quality [F(11,198) = 1.92; p = 0.038]. In that,  the subjects' sleep quality decreased over time in subjects who exercised compared to condition controls (sedentary). In contrast to what you'd expect, though, it were not the subjects who worked out and consumed caffeine who had the lowest sleep quality, but those "who exercised and received placebo [who] had the lowest overall average sleep quality" (O'Brien. 2016).

What may come as a surprise is that this decline in sleep quality had no effect on the subjects' perceived tiredness (Figure 2, right), which showed a main effect of time for ‘Body Feels Tired’ [F(11, 154) = 2.1; p = 0.026], but no treatment (placebo/caffeine) or condition (sedentary/exercise) interactions - which is unquestionably odd. About as odd, as the misleading statement that "[p]oorest sleep quality ratings associated with caffeine and exercise" (O'Brien. 2016) from the scientists' own summary of the results. Now, don't get me wrong. This statement is correct, but only if we are talking about the individual effects of exercise / sedentary and caffeine / placebo, on their own. The way O'Brien et al. phrased it, does however appear to suggest that the subjects' sleep was worst during the exercise + caffeine trials... Now, that, in turn, is what you probably expected the study to show, but another brief glance at the data in Figure 2 (left) confirms: caffeine did not mess with the subjects' sleep quality. In fact, the group with the most stable sleep quality are the sedentary coffee drinkers . eventually, you could thus argue that they had the best sleep quality!

High Dose Caffeine Restores Insulin Sensitivity and Limits Sugar-Induced Total + Visceral Fat Gain . That's in contrast to the still prevalent message that caffeine would ruin your insulin sensitivity | more

Bottom line: As the authors point out, "[e]xercise and caffeine did not have the hypothesized results on sleep quality and duration" (O'Brien. 2016). Instead of improving the sleep quality of the subjects, as it has been observed previously in both, middle-aged and older adults (Yang. 2012) and young healthy sleepers (Flausino. 2012), exercise clearly reduced the young subjects' sleep quality in the study at hand. As O'Brien et al. point out, this may have been a function of the novelty of the exercise and subsequent "physical discomfort that disrupted sleep quality and duration" of the previously untrained subjects in the study at hand, so that the results would change over time / be different if the study had used trained individuals.

Another important subject characteristic that may have "messed" with the results were the sujects' individual habitual caffeine consumption (100mg/day on average). Even though their habitual intakes were low, the fact that caffeine did not, as it did in previous studies, per se mess with the subjects' sleep quality, but rather improved it, could, as O'Brien et al. suggest, be due to "[w]ithdrawal reversal" of which the scientist argue that it appears to be "the primary action mechanism of caffeine [in the study at hand]" (O'Brien. 2016). Practically speaking, this would mean that "[r]eversing [the] negative state [of being on caffeine withdrawal] through caffeine administration improved [not decreased the subjects'] sleep quality and duration" (O'Brien. 2016 | my emphasis). How realistic this assumption is does yet appear questionable, with std. deviations of <50mg/day, the subjects don't seem to be caffeine junkies and with a dosage of only 3mg/kg per day (all subjects were normal weight, so that's probably in the 200-300mg range) switching from a caffeine to a no-caffeine group in the 2nd of the 2x2 week phases doesn't appear to be likely to induce significant "caffeine withdrawal", either. I am thus doubly curious to see the (hopefully) full dataset, when this intriguing study is eventually published (also because the the caption of Figure 1 in the "FT" says that there was no interaction with habitual caffeine intake for sleep duration, at least). In the mean time, I'd suggest you simply listen to your body. The effects of exercise and caffeine on one's sleep are, after all, just as so many things, highly individual | Comment!

References:

• O’Brien, E, et al. "Caffeine and Exercise Affect Sleep Duration, Quality and Perceived Tiredness." Department of Exercise and Nutrition Sciences---University at Buffalo, Buffalo, NY (Poster presentation).
• Yang, Pei-Yu, et al. "Exercise training improves sleep quality in middle-aged and older adults with sleep problems: a systematic review." Journal of physiotherapy 58.3 (2012): 157-163.

High Dose Caffeine Restores Insulin Sensitivity and Limits Total as Well as Visceral Fat Gain Due to High Sugar Diets

High Dose Caffeine Restores Insulin Sensitivity and Limits Total as Well as Visceral Fat Gain Due to High Sugar Diets

caffeine coffee fat gain glucose management health high sugar insulin sensitivity lose fat obesity sugar type II diabetes visceral fat

Yes, the study at hand is on caffeine, but the results are relevant for coffee, too.

A decade ago, the medical community though coffee would dehydrate you, would make you insulin resistant and would increase your risk of heart disease. Recent studies show that coffee does not negatively affect your hydration status (Killer. 2014), that higher coffee consumption is associated with reduced diabetes risk and increasing your coffee consumption can reduce your risk of T2DM (Akash. 2014) and that a "daily intake of ∼2 to 3 cups of coffee appears to be safe and is associated with neutral to beneficial effects" on coronary heart disease, congestive heart failure, arrhythmias, and stroke (O'Keefe. 2013).

Against that background it may not be as surprising as it would have been 10 years ago that Joana C. Coelho, et al. (2016) found caffeine to be able to restores insulin sensitivity and glucose tolerance in high-sucrose diet rats. And yet, I personally believe that it is still worth pointing out the results of this study as the high sucrose diet the mice were fed is the same "high sugar diet" about which you will read all over the news that it is to blame for the obesity and diabetes epidemic.

You can learn more about coffee and caffeine at the SuppVersity

For Caffeine, Timing Matters! 45 Min or More?

Coffee - The Good, Bad & Interesting

Three Cups of Coffee Keep Insulin At Bay

Caffeine's Effect on Testosterone, Estrogen & SHBG

The Coffee³ Ad- vantage: Fat loss, Appetite & Mood

Caffeine Resis- tance - Does It Even Exist?

Against that background, it is particularly interesting to take a closer look at the data from Coelho's study, because it is the first to actually provide a valid explanation for the observed improvements in glucose sensitivity in response to the ingestion of caffeine.

Figure 1: 16-wk food intake, weight gain, fat gain and visceral fat gain according to caffeine intake (Coelho. 2016).

Now, the bad news is that significant effects were only observed for the highest dose of caffeine, ie..e 1g/L drinking water. That appears to be ridiculously high, but is in fact only "very high". If you do take into consideration that a wistar rat consumes only 100 ml/kg body weight per day, that's a dosage equivalent of 100 mg/kg for a rodent and thus ~16 mg/kg for a human being or ~6-7 cups of coffee (over a 24h period).

University of Memphis: Caffeine can help control the increase in blood lipids and oxidation after inhaling (10 minutes) a high calorie + high fat milk shake, controlled trial involving twelve healthy men shows (Crone. 2016).

Yes, the dosage is high, but actually less may have more benefits, and...  the most relevant benefits (reduced fat gain) were seen at a dosage that would be equivalent to only 4-5 cups of coffee, which happens to be roughly what epidemiological studies show to be in the zone of maximal benefits. Don't mistake this as a recommendation to guzzle liters of coffee, though... and that even if another recent study shows that 400mg of caffeine will lower the fatty acid onslaught and oxidation 12 men experience after consuming a large high fat milk-shake (Crone. 2016)... and speaking of coffee: you may also want to make sure to get a dark roast, because the latter has just been found to improve glucose metabolism and redox balance even if it is low in caffeine (Di Girolamo. 2016). 

While I am not sure how healthy the chronic consumption of these amounts of caffeine actually is. I am aware of several people who get their 6-7 cups of regular coffee per day and are in perfect health. With that being said, the latter may be at least partly due to the the highly beneficial effects of caffeine on the expression of glucose transporter 4 (GLUT4) and insulin receptor expression and phosphorylation (not shown in Figure 2) in the visceral fat depots of coffee connaisseurs.

Figure 2: Effects of different doses of caffeine on GLUT4 and insulin receptor expression in rats (Coelho. 2016).

The above elevations were accompanied by profound increases in protein kinase B (Akt) expression and activity, as well - an observation the scientists regard as being evidence of the fact that "[c]hronic caffeine administration improved whole-body glucose homeostasis and insulin signaling pathways in adipose tissue" (Coelho. 2016).

This conclusion cannot be questioned. What can be questioned, though, is the scientists assumption that this would occur only with high doses of caffeine and in response to increases in GLUT4 and insulin receptor expression in the visceral fat. Why's that? Well take a look at the figure in the bottom line: it shows that significant improvements in glycemia were improved at all dosages. The latter wouldn't have been possible if the lower dosages wouldn't have had an effect on glucose uptake, as well. Whether that's an effect in muscle cells (which would be great), needs further investigation. The previously discussed effects of caffeine on muscle glycogen storage (learn more), on the other hand, would suggest just that: an effect on skeletal muscle, and or a reduction in gluconeogenesis which could, among other things, be triggered by coffee's / caffeine's ability to inhibit the reactivation of glucocorticoids by 11β-hydroxysteroid dehydrogenase type 1" (Atanasov. 2006).

As you can see sign. improvements in glycemia occured even with the lowest amount of caffeine in the drinking water. And that in spite of the fact that the GLUT4 and insulin receptor levels in the visceral fat did not increase significantly... well, maybe those in the rodents' muscle did?

Bottom line: I am not suggesting that the rodent study at hand would provide enough evidence to suggest that everyone should drink at least 4 cups of high caffeine coffee per day. What I do suggest, however, is that the study at hand provides more evidence on potential mechanisms that explain why coffee drinkers are plagued less often by metabolic disease.

With that being said, I would like to remind you that the abuse of caffeine to combat a lack of sleep and/or overtraining may make you dig a deep black hole out of which you will be able to crawl only within weeks of abstinence... and I am talking about abstinence from caffeine and exercise, assuming that it was the combination of both that got your into trouble | Comment on Facebook!

References:

• Akash, Muhammad Sajid Hamid, Kanwal Rehman, and Shuqing Chen. "Effects of coffee on type 2 diabetes mellitus." Nutrition 30.7 (2014): 755-763.
• Atanasov, Atanas G., et al. "Coffee inhibits the reactivation of glucocorticoids by 11β-hydroxysteroid dehydrogenase type 1: A glucocorticoid connection in the anti-diabetic action of coffee?." FEBS letters 580.17 (2006): 4081-4085.
• Coelho, Joana C., et al. "Caffeine Restores Insulin Sensitivity and Glucose tolerance in High-sucrose Diet Rats: Effects on Adipose Tissue."
• Crone, et al. "Impact of Meal Ingestion Rate and Caffeine Coingestion on Postprandial Lipemia and Oxidative Stress Following High-Fat Meal Consumption." Journal of Caffeine Research (2016): Ahead of print. DOI: 10.1089/jcr.2016.0004.
• Di Girolamo, Filippo Giorgio, et al. "Roasting intensity of naturally low-caffeine Laurina coffee modulates glucose metabolism and redox balance in humans." Nutrition (2016).
• Killer, Sophie C., Andrew K. Blannin, and Asker E. Jeukendrup. "No evidence of dehydration with moderate daily coffee intake: a counterbalanced cross-over study in a free-living population." PloS one 9.1 (2014): e84154.
• O'Keefe, James H., et al. "Effects of habitual coffee consumption on cardiometabolic disease, cardiovascular health, and all-cause mortality." Journal of the American College of Cardiology 62.12 (2013): 1043-1051.

Caffeine & Bicarbonate - Individuality is Key: Using Supps That Work for You Make a >90% Performance Difference

Caffeine & Bicarbonate - Individuality is Key: Using Supps That Work for You Make a >90% Performance Difference

bicarbonate caffeine cycling endurance ergogenic ergogenics NAHCO3 natural ergogenic performance sodium bicarbonate time to exhaustion

Right vs. wrong supps can make a victory or defeat difference of >90%.

I've written about the individual response to caffeine and bicarbonate before. To tackle both of these ergogenic supplements I can actually recommend, however, based on a single study that as just been published in the Applied Physiology, Nutrition, and Metabolism is news. The study was conducted at the Derby University's Department of Life Sciences, Sport, Outdoor & Exercise Science (Higgins. 2016) and evaluated the effects of ingesting sodium bicarbonate (NaHCO3) or caffeine individually or in combination on high-intensity cycling capacity.

In a counterbalanced, crossover design, 13 healthy, noncycling trained males (age: 21 ± 3 years, height: 178 ± 6 cm, body mass: 76 ± 12 kg, peak power output (Wpeak): 230 ± 34 W, peak oxygen uptake: 46 ± 8 mL·kg−1·min−1) performed a graded incremental exercise test, 2 familiarisation trials, and 4 experimental trials.

You can learn more about bicarbonate and pH-buffers at the SuppVersity

The Hazards of Acidosis

Build Bigger Legs W/ Bicarbonate

HIIT it Hard W/ NaCHO3

Creatine + BA = Perfect Match

Bicarb Buffers Creatine

Instant 14% HIIT Boost

Trials consisted of cycling to volitional exhaustion at 100% W peak (TLIM) 60 min after ingesting a solution containing either

• 0.3 g·kg−1 body mass sodium bicarbonate (BIC), 
• 5 mg·kg−1 body mass caffeine plus 0.1 g/kg body mass sodium chloride (CAF), 
• 0.3 g·kg−1 body mass sodium bicarbonate plus 5 mg/kg body mass caffeine (BIC-CAF), or 
• 0.1 g·kg−1 body mass sodium chloride (PLA). 

Experimental solutions were (supposedly) administered double-blind (which is difficult imho, because bicarb and salt taste different, but alas).

Figure 1: Tabular overview of the rate of perceived exertion (RPE_L = legs, RPE_O = overall cardiovascular strain | left) and blood pH over time (right) during the four trials (Higgins. 2016).

The first and most obvious effect of treatments (BIC) and (BIC-CAF) was a significant increase in pH, base excess, and bicarbonate ion concentration ([HCO3−]) compared to the CAF and PLA trials.

Another new study supports lower dose (0.3g/kg) bicarbonate for resistance training: The study was conducted by a Bachelor student from the University of Tempa. The purpose of the study was to investigate whether the ingestion of sodium bicarbonate (SB) pre-exercise improved athletic performance during resistance training (RT) and reduced fatigue in male college students. In the study, ,ale college students performed 1RM and endurance tests before their own individualized RT program 4 times a week during the 4 week study. The SB group produced higher increases in mean weight used in each of the 1RM tests (P < 0.05) compared to the placebo group. The SB group also produced a higher amount of repetitions in the IDP, LP, and LPD endurance tests (P < 0.05). There was a significant difference in each self-report scale (P < 0.05) between the SB group and the placebo group. "These findings suggest that the supplementation of SB prior to RT in college male students could enhance performance," (Indorato. 2016) the author concludes.

The effect on TLIM (time to volitional exhaustion) was unfortunately less obvious - for all three active treatments, by the way. When all subjects were considered, ...

• 

  A high amount of alkali in your diet could have general health and performance benefits | learn more

  there was a significant increase in TLIM for CAF (399; 350–415 s; P = 0.039; r = 0.6) and BIC-CAF (367; 333–402 s; P = 0.028; r = 0.6), but only compared with BIC (313: 284–448 s), yet not compared with PLA (358; 290–433 s; P = 0.249, r = 0.3 and P = 0.099 and r = 0.5, respectively), 
• there were no differences between PLA and BIC (P = 0.196; r = 0.4) or between CAF and BIC-CAF (P = 0.753; r = 0.1), and 
• there was no effect whatsoever on the rate of perceived exertion (RPE | Figure 1, left).

The "average" effect does yet not tell you the full truth about the potential ergogenic effects of caffeine and bicarbonate. Why? Higgins et al. found very large inter- and intra-individual variations, when they compared the individual treatments (see Figure 2, right).

Figure 2: Mean +/- SD (left) and individual (right) response to the treatments (Higgins. 2016).

Accordingly, the scientists rightly highlight that optimal supplementation strategies require individualization. Using supplements that work for you can, after all, make a performance difference of 81%, 92% and 63% (max. vs. min responders) for bicarbonate, caffeine and the combination of both (all values relative to T_LIM in the placebo trial).

Caffeine has many benefits, but also potential downsides you should know about to make an educated decision based on science and your individual response to caffeine | learn more

Fine. So shall I use bicarbonate and caffeine or not? I cannot tell you that. Why? Well, it depends on how you react to these proven ergogenics. The only way to find out is to testdrive both - on their own and together. Plus: A study investigating the maximal cycling time at 100% of your peak wattage doesn't tell you sh*t about the effects on your performance during other physical activities like resistance training (the study in the red box, does, though).

Luckily, the new study by Indorato is not the only one to show bicarbonate (example) has, just like caffeine, by the way (example), ergogenic effects . This doesn't mean that either of them will necessarily work for you, but it is a good reason to trial both | Leave a comment on Facebook!

References:

• Higgins, et al. "Evaluating the effects of caffeine and sodium bicarbonate, ingested individually or in combination, and a taste-matched placebo on high-intensity cycling capacity in healthy males." Appl. Physiol. Nutr. Metab. (2016).
• Indorato, Daniel. "Enhanced Resistance Training Performance via the Neutralization of Lactic Acid with Sodium Bicarbonate." Student Pulse 8.03 (2016).

Caffeine Keeps You Going When You'd Usually Rack the Weight - Does That Cause an Increase in Muscle Damage?

Caffeine Keeps You Going When You'd Usually Rack the Weight - Does That Cause an Increase in Muscle Damage?

caffeine CK coffee lactate performance rhabdomyolysis training

With only 65mg of caffeine, an espresso provides only ~12.5% of the amount of caffeine used in the study at hand.

If you've kept an eye on the latest caffeine research you may have noticed that there's an increasing number of studies that fails to find significant performance enhancing effects of caffeine during resistance training sessions (Trevino. 2015). Does this mean that caffeine, a substance that is by the way on the World Anti-Doping Agency's list of prohibited substances useless for gymrats? Certainly not.

One thing most of these studies have in common is that they tested the subjects' strength or power production during short workouts. Studies that investigate the effects of caffeine in higher volume contexts, on the other hand (e.g. Lang. 2015; Thomas. 2015), confirm that caffeine is rightly the most (ab-)used ergogenic among fitness enthusiasts.

You can learn more about coffee and caffeine at the SuppVersity

For Caffeine, Timing Matters! 45 Min or More?

Coffee - The Good, Bad & Interesting

Three Cups of Coffee Keep Insulin At Bay

Caffeine's Effect on Testosterone, Estrogen & SHBG

The Coffee³ Ad- vantage: Fat loss, Appetite & Mood

Caffeine Resis- tance - Does It Even Exist?

One thing that has recently caught my attention on Facebook is the claim that the performance enhancing effects of caffeine put you at risk of rhabdomiolysis, i.e. the potentially dangerous breakdown of muscle tissue. In theory, it'd appear logical to assume that an agent that has repeatedly been proven to significantly lower the perceived exertion/fatigue as well as muscle pain during exercise could lead to a greater degree of muscle damage during exercise.

Figure 1: Graphical overview of the experimental design of Ribiero's study (Ribiero. 2016).

To test the hypothesis that acute caffeine ingestion could attenuate leg power, and increase blood lactate at the expense of increased muscle damage, researchers from the Federal University of Rio de Janeiro recruited six male pro handball athletes who layed in the first division of the Brazilian National League of Handball (HBNL).

"All of them had at least 5 years of experience in the sport and trained for about 4 hours a day, 4-5 days a week. No athlete had a previous medical history of cardiopulmonary disease or used any medication during the study. The athletes reported intake of ~ 60 mg of caffeine per day (~ 1 cup of coffee)" (Ribiero. 2016).

In a randomized, placebo-controlled, double-blind crossover study, the subjects reported to the laboratory at two occasions after an 8-h fast and at least 24h of caffeine abstinence. 60 minutes after having a standardized breakfast, which consisted of bread, white cheese, and orange juice (CHO: 87 g, 348 kcal; PTN: 13.5 g, 54 kcal; LIP: 7 g, 63 kcal; Total: 465 kcal), they consumed either placebo (PLA), or caffeine (CAF; 6mg/kg body weight) and remained seated for another 60 minutes.

But this is not resistance training! While you're absolutely right, jumping is at least as notorious for producing muscle damage as regular resistance training. It is thus unlikely that leg presses or squats would have produced a greater degree of muscle damage than this intense VJ protocol.

After the 60-minute delay during which the serum caffeine levels rose to peak values (see previous SuppVersity article), they performed a short warm-up and a standardized vertical jump test the scientists describe as follows:

Figure 2: Mean leg power during VJ (Ribiero. 2016).

"The VJ performance was evaluated by the jump platform System Optical (Cefise®, São Paulo, Brazil). This equipment consists of a laptop with the software "Jump System" (version 1.0, São Paulo, Brazil), connected by a cable to a resistive (or capacitive) platform (equipped with infrared optical sensors). The timer software is triggered by the feet of the subject at the moment of release from the platform, and will be stopped at the moment of touchdown. This equipment has the same principle of “Ergojump” to inform the flight time (ms) and contact (ms). 

The error of measurement, when compared with film analysis has been reported to be in the order of ± 2% (18). The athlete was positioned, barefoot, in the interior of the platform and the jumps were performed starting from a standing position until approximately at an angle of 90° knee, using help from upper limbs at the time of the VJ execution" (Ribiero. 2016).

The VJ data were analyzed by average leg power (Watts/Kg) generated by the athletes. In that, the scientists separated the total number of vertical jumps into tertiles, so that they could have an understanding of the behavior of the jumps in the 1st tertile (i.e., theoretically better performance), in the 2nd tertile (i.e., theoretically an average performance), and 3rd tertile (i.e., theoretically a drop in performance).

Your muscle is not the only thing that could be overtaxed - Even though the ability to perform more sets / work out more intensely / longer may not have affected the primary marker of muscle damage in the study at hand, the chronic consumption of high doses of caffeine may still pose a risk to your central nervous system and contribute to sympathetic overtraining. Therefore I'd still recommend you stick of max. 400-600 mg caffeine per day and, instead of increasing the dosage, when it stops working, take a "caffeine break" whenever you stop noticing the "caffeine spike".

This allowed Ribiero et al. to make comparisons between groups and to assess the effects of supplementation. Effects of which the data in Figure 3 tells you that they became evident only in the latter tertile of jumps:

Figure 3: Nonlinear regression analyses (polynomial regression 3rd order). Leg of the power generated in each sets of athletes with tertiles in placebo (PLA) and caffeine (CAF) trials (Ribiero. 2016).

As you can see in Figure 2, the subjects hit the wall in said third tertile in the placebo trial. In the supplement trial, on the other hand, the performance decline was significantly ameliorated - not only, but especially during the first and second set (black squares and white circles). This effect becomes even more obvious when you take a look at the leg power the subjects exerted on the jump platform during the jumps in the 1st, 2nd and 3rd tertile (plotted in Figure 2): compared to the use of placebo caffein improved the leg power the of athletes in the 3rd tertile (p <0.05) by 5.23%.

At the same time, however, it lead to a highly significant increase in blood lactate levels (+42.59%) after the execution of vertical jump test (p <0.05). In contrast to what the initially discussed hypothesis would suggest, though, this increase in lactate was not accompanied by significant increases in serum CK levels of the athletes (see Figure 4).

Figure 4: On average, the increase in CK was even lower in the caffeine trial - albeit not significantly (Ribiero. 2015).

So what does that mean? Well, the most obvious answer certainly is that using caffeine to boost your performance beyond "natural limits" is not going to increase your risk of rhabdomiolysis. On the other hand, the study doesn't say anything about the effects on the central nervous system and whether your CNS, not your muscle, could be overtaxed by "going beyond failure" with caffeine.

The potential negative effects of chronic caffeine consumption on the central nervous is a problem I've mentioned in the red box and discussed in previous articles about caffeine.

Unfortunately, this problem has not been sufficiently studied, yet. So, if you're looking for a supplement related topic for your master thesis, boys and girls, the effects of chronic pre-workout caffeine consumption at different dosages on the central nervous system could be just the topic you've been looking for ;-) | Comment on Facebook!

References:

• Lang, K., and E. B. LaFountaine. "Effects of caffeine as an ergogenic aid on weight lifting regimes in male collegiate athletes." International journal of exercise science: Conference proceedings. vol. 12. no. 1. 2015.
• Thomas, Gabrielle. Is coffee an effective pre-workout drink?–The effects of ingesting naturalistic doses of caffeine on one-repetition maximum muscular strength and muscular endurance in females. Diss. Cardiff Metropolitan University, 2015.
• Ribiero, et al. "Caffeine attenuates decreases in leg power without increased muscle damage." Journal of Strength and Conditioning Research (2016): Publish Ahead of Print | DOI: 10.1519/JSC.0000000000001332
• Trevino, Michael A., et al. "Acute Effects of Caffeine on Strength and Muscle Activation of the Elbow Flexors." The Journal of Strength & Conditioning Research 29.2 (2015): 513-520.

Non-Stimulant, Non-Effective?! Can Non-Stimulant Dietary Herbal Supplements Boost Your Resting Metabolic Rate?

Non-Stimulant, Non-Effective?! Can Non-Stimulant Dietary Herbal Supplements Boost Your Resting Metabolic Rate?

caffeine cellucor CLA fat burner lose fat non-stimulant raspberry ketones REE stims stimulant

There are two types of alleged fat burners: Type I are the stimulants with proven beneficial effects on you resting metabolic rate and beneficial "side effects" on energy levels and (reduced) appetite. Type II are non-stimulant "fat burners". Two of those have been tested in a recent study ... learn what the study says.

Amanda J. Salacinski, Steven M. Howell, Danielle L. Hill, & Steven M. Mauk, researchers from the Department of Kinesiology and Physical Education at the Nothern Illinois University didn't miss that weight loss supplements are becoming increasingly popular - even in people with with chronic diseases (usually as a consequence of obesity).

Even in healthy individuals, the list of side effects that have been reported for the various fat burners is long (Salacinski et al. highlight G.I. distress, and liver inflammation, which may accompany weight loss resulting from chronic supplementa-tion, in particular)... and while it is long, very long, in fact, it is hardly science based, because evidence controlled treatment trials in healthy and diseased patients are rare, insufficient or simply lacking. That's bad news. After all, for most currently marketed OTC weight loss agents' kitchen-sink approach to fat loss, there's no evidence that they even work.

If you're looking for a true fat burner, try coffee ;-)

For Caffeine, Timing Matters! 45 Min or More?

Coffee - The Good, Bad & Interesting

Three Cups of Coffee Keep Insulin At Bay

Caffeine's Effect on Testosterone, Estrogen & SHBG

The Coffee³ Ad- vantage: Fat loss, Appetite & Mood

Caffeine Resis- tance - Does It Even Exist?

One example the scientists mention are raspberry ketones which have, as the scientists point out, "been widely promoted as a ‘weight loss miracle’ [even though there's more than just] limited research [...] on humans" (Salacinski. 2016); and still, raspberry ketones are at least an ingredient of which you know that it could be working... to some degree. That is in contrast to what the scientists say is true for the majority of products on the US market, which "have inconclusive labels or contain a ‘metabolic activator blend’ which includes no details on the ingredients for weight loss" (Salacinski. 2016). Furthermore, ...

Figure 1: There's no doubt that there was an effective fat burner on the market. The com-bination of ephedrine and caffeine (data from Greenway et al. 2004) did what pharma-cological bogus like "Alli" will never do: burn fat and protect muscle (e.g. Molnar. 2000)

"[...t]he Dietary Supplement Health and Education Act (1994) allows for the marketing of supplements without prior approval of their efficacy and safety by the Food and Drug Administration (FDA). Therefore, the safety profiles for many of these products are unknown, thus leading to variations in their composition and allows for the inclusion of inferior products (Stickel et al., 2005). Moreover, the majority of the research conducted within this area has primarily focused on the use of caffeine, chromium, and ephedra for weight loss, which contributes to increase user confusion and product uncertainty (Anderson, 1998; Greenway et al., 2004; Urbina et al., 2012)" (Salacinski. 2016).

As a more recent study by Urbina et al. (2012) appears to suggest, it doesn't necessarily take ephedrine, though, to elicit significant increases in metabolic rate. The ephedrine-free caffeine + green tea based successor to the ephedrine-based fat burner DymaBurn(TM) may not be as effective, but can still elevate the resting metabolic rate of  6 male and 6 female subjects (N = 12, 22 ± 9.5 yrs, 171 ± 11.2 cm, 76.9 ± 11.2 kg, 22.7 ± 9.5), who consumed either a 2 capsule serving of Dyma-Burn Xtreme (DBX) or placebo (PLC), significantly (see Figure 2):

Figure 2: Effects of the ephedrine-free version of DymaBurn (caffeine, green tea extract, raspberry ketones and L-carnitine) fat burner and placebo on resting metabolic rate at 1h, 2h, 3h and 4h after ingestion; values in kcal / day (Urbina. 2012).

The same goes for the desired "side effects", namely an improved state of mood state that involves increased focus, alertness, and energy (Urbina. 2012)... all three effects are characteristic of stimulants, though, and thus exactly those fat burner ingredients of which Salacinski et al. wanted to determine whether they could be replaced with non-stimulant herbal supplements.

Citrus aurantium is not the valid successor to ephedra marketing campaigns tell you. In fact, Bent et al. found only one reliable placebo-controlled study which yielded the disappointing results you see above (Colker. 1999)

No fat burner "burns fat": Among those agents that won't possibly kill you in no time, none will actively burn fat - not even those that have been proven to trigger significant increases in fat oxidation, like caffeine or green tea. They may help you to shift the weight loss towards body fat, but the <125kcal/day increase in resting metabolic rate from the caffeine + GTE combination I plotted for you in Figure 2 is not going to get you ripped without the help of concomitant dieting efforts.

Fat burners are no magic weight loss pills and still, they can help you lose weight - especially the stim-based ones - because they may reduce appetite, increase energy and thus your ability to adhere to an energy restricted diet with or without concomitant exercise.

Supplements like the kitchen-sink blend CelluCor CLK or the previously mentioned raspberry ketones. Two agents Salacinski et al. administered to 10 healthy female and 16 male participants (mean age 23.7 ± 3.9 years; mean weight 79.2 ± 18.2 kg) in a complex experiment. The latter involved three trials on separate days during the morning hours (0600–1100) during a 2-week interval.

Figure 3: Changes in RMR after the administration of raspberry ketones or CelluCor CLK; p  > 0.05 for both (Salacinski. 2016).

"As recommended by Compher and colleagues (2006), subjects were instructed to refrain from exercising for 24 hours and from consuming food for 12 hours prior to testing. The participant ingested a placebo (an empty digestible capsule) or a dose of one of two supplements; CelluCor CLK or raspberry ketones (R) and CelluCor T7 or the metabolic activator blend (MAB) with water, upon awakening on the morning of each measurement session. The three softgel and two softgel tablets were considered to be a single dose of R and MAB, respectively, as recommended by the manufacturer.

R was composed of 1.7 g of conjugated linoleic acid, 500 mg of l-carnitine tartrate, 100 mg of R, and 100 mg of 7-ketodehydroepiandrosterone. The MAB product consisted of 494 mg of MAB with an ingredient list of white willow bark, cayenne, 3-iodotyrosine, 3, 5-diiodotyrosine, 200 mg of zinc arginate chelate, 150 mg of sea weed extract. 66 mg of niacinamide, 66 mg of griffonia seed extract, and 0.2 mg of selenium" (Salacinski. 2016).

The placebo (control trial) was always ingested on the morning of the first measurement session two hours prior to measurements. The supplement (R or MAB) taken upon awakening prior to the second and third measurement session was randomly determined by a coin toss, again two hours before the data collection. Whichever supplement was not taken prior to the second measurement trial was taken prior to the third measurement trial. At least 24 hours separated the first session (control) with the second session; and at least 48 hours separated the second session from the third session to minimize interference from the previous supplement.

The results of this recent rel. small scale (N=26, no dropouts) study are plotted in Figure 3. Data from two participants were excluded from the statistical analysis because the data could not be adjusted to meet the acceptable criteria recommended by Compher et al. (2007) and Frankenfield et al. (2003). Despite the two exclusions, it should be obvious that the non-significant 0.111% increase due to raspberry ketones and the even lower increase due to CelluCor CLK are meaningless.

Onakpoya, et al. conducted a comprehensive meta-analysis on the weight loss effects of CLA. The analysis shows a non-significant trend for increased weight loss with increasing dosages of conjugated linoleic acid, but overall, their results do "not convincingly show that CLA intake generates any clinically relevant effects on body composition on the long term" (Onakpoya. 2012).

Bottom line: In view of the fact that the study at hand is an acute response study, I have to admit that it is remotely possible that any of the supplements tested could still trigger long-term fat loss, Salacinski et al. rightly point out that their study refutes the often-heard claim that non-thermogenic herbal supplements would be a fit and safe alternative to stimulants. A replacement that would facilitate similar increases in RMR as nowadays mostly caffeine-based thermogenics without side effects.

Irrespective of any methodological gaps, the study at hand suggests shows one thing with a decent certainty: if raspberry ketones alone or RK blends like CelluCor CLK, which contains hydrolysates of Blue Whiting, L-Carnitine Tartrate, CLA (Conjugated Linoleic Acid) and Razberi-K®, a proprietary raspberry extract marketed as "the original ketone ingredient behind this movement", work at all - it is not by increasing your REE | Comment!

References:

• Anderson, Richard A. "Chromium, glucose intolerance and diabetes." Journal of the American College of Nutrition 17.6 (1998): 548-555.
• Bent, Stephen, Amy Padula, and John Neuhaus. "Safety and efficacy of citrus aurantium for weight loss." The American journal of cardiology 94.10 (2004): 1359-1361.
• Colker, Carlon M., et al. "Effects of Citrus aurantium extract, caffeine, and St. John's wort on body fat loss, lipid levels, and mood states in overweight healthy adults." Current Therapeutic Research 60.3 (1999): 145-153.
• Greenway, Frank L., et al. "Effect of a Dietary Herbal Supplement Containing Caffeine and Ephedra on Weight, Metabolic Rate, and Body Composition*." Obesity research 12.7 (2004): 1152-1157.
• Molnar, D., et al. "Safety and efficacy of treatment with an ephedrine/caffeine mixture. The first double-blind placebo-controlled pilot study in adolescents." International Journal of Obesity 24.12 (2000): 1573-1578.
• Onakpoya, Igho J., et al. "The efficacy of long-term conjugated linoleic acid (CLA) supplementation on body composition in overweight and obese individuals: a systematic review and meta-analysis of randomized clinical trials." European journal of nutrition 51.2 (2012): 127-134.
• Salacinski, Amanda J., et al. "The Acute Effects of Nonstimulant Over-the-Counter Dietary Herbal Supplements on Resting Metabolic Rate." Journal of dietary supplements (2015): 1-10.
• Stickel, Felix, Eleonora Patsenker, and Detlef Schuppan. "Herbal hepatotoxicity." Journal of hepatology 43.5 (2005): 901-910.
• Urbina, Stacie, et al. "Effects of ingesting Dyma-Burn Xtreme, a thermogenic dietary supplement on metabolic rate and subjective measures of mood state." JISSN 9.Suppl 1 (2012): P31.