Endurance Athletes May Benefit From High-GI Meals Before Competition: 18% Increased Endurance During Time Trial

Endurance Athletes May Benefit From High-GI Meals Before Competition: 18% Increased Endurance During Time Trial

GI glucose glycemic index high GI low GI performance preworkout time to exhaustion TTE

Hillariously sweet, super cheap, and surprisingly effective: glucose!

While most of you will probably already have discarded the notion that you can only lose weight if you eat a diet with an extremely low GI (on a side note: Taubes' own study falsified his "insulin theory of obesity", recently), the notion that the ingestion of high glycemic index foods before exercise could ruin your performance, because your glucose levels, after an initial spike, will plummet and you will crash, still looms large.

With that being said, athletes around the world have, somewhat paradoxically, stuck to complex carbs before competition only to then fuel their performance with extremely sugary intraworkout bars, gels and drinks.

Are you a workout junkie? Try bicarbonate or other pH-buffers

Caffeine & Bicarb = Perfect Match

Build Bigger Legs W/ Bicarbonate

HIIT it Hard W/ NaCHO3

Creatine + BA = Perfect Match

Bicarb Buffers Creatine

Instant 14% HIIT Boost W/ Bicarb

Now, a recent study from the University of Florida, shows that "a fiber-free, glucose-derived meal may be superior to a low glycemic fiber-free whole meal in supporting moderately high intensity exercise in some highly motivated recreationally trained endurance athletes" (my emphasis in Waggener. 2016) - not exactly what you'd expect, right?

No reason to feel embarrassed, though: Even the authors of said study expected that their likewise fiber-free whole milk supplement with a low glycemic (LGM | GI = 41), would "equal or surpass the effects of an iso-kilocaloric, high glycemic (HGM) pre-exercise meal of glucose" (GI = 100).

Timing + intensity (and fiber) may matter, here! While there are surprisingly few studies that actually compare high vs. low GI carbohydrate sources pre-workout, a 2001 study by Kirwan using totally different CHO-sources (2 different breakfast cereals: rolled oats (moderate GI, 61; MOD-GI) or puffed rice (high GI, 82; HI-GI), combined with 300 mL of water) suggests that high-fiber low GI meals are advantageous if (a) the time-trial begins after 45 minutes of rest (instead of 2h of medium-intensity exercise) and you are (b) training / competing at a low intensity of only 60% VO2peak and thus for 2h+, which is obviously not exactly representative of endurance sports competitions or resistance training workouts w/ higher intensities.

Furthermore, the scientists expected that both would kick the ass of an artificially flavored placebo. when either of the three treatments was consumed 30 minutes before a 2-hr submaximal steady state ride at 55% of VO2 max that was followed by brief rest, and then by a final time-trial to exhaustion on the cycle ergometer (TTE) at 80% of VO2 max - the test was repeated on three separate days.

"The test drinks in this study consisted of whole cow’s milk (837.2 kJ / 320 ml fluid volume: 16 g carbohydrate, 10.7 g fat, and 10.7 g protein; Publix, Inc.) and two contrast drinks, one consisting of glucose polymer drink iso-kilocaloric to the whole milk supplement (837.2 kJ / 300 ml fluid volume: 50 g carbohydrate, 0 g fat, and 0 g protein; Cardinal Health, McGraw Park, IL) and a placebo/control drink (water). The placebo was an artificially flavored, unsweetened beverage (2 g of NutraSweet in 300 ml bottled water; [...])" (Waggener. 2016).

To avoid that the subjects' baseline diet would mess with the results, the diet in the days before the test was standardized (high in carbs 60.5% = typical end. athlete diet) and controlled via food logs.

Figure 1: Stamina (length in minutes) during the time trial after 1h of low-medium intensity exercise (Waggener. 2016).

Much in contrast to what the scientists expected, the LGM (whole milk) did not exert a greater ergogenic effect in this study when compared to the isokilocaloric HGM (glucose).

In fact, there was a non-significant (+18% time to exhaustion, blue bar in Figure 1 | not significant due to the large inter-individual differences) advantage for the HGM meal, which outperformed both, the LGM and the placebo on the most important test: the time to exhaustion trial - and that in spite of the fact that it was performed after a 2h! medium intensity workout, during which the subject's serum glucose and insulin levels should have performed the initially hinted at, purportedly ergolytic (=the opposite of performance-enhancing) roller-coaster ride.

Ah, and before you ask: The carbs - high or low GI - did not reduce the fat oxidation, the respiratory quotient was the same. Intra-workout fat oxidation doesn't matters much (or not at all) for fat loss, but alas... (Waggener. 2016).

Bottom line: As surprising as it may seem, the scientists' conclusion that a glucose-derived meal "may be superior to a low glycemic fiber-free whole meal in supporting moderately high intensity exercise in some highly motivated recreationally trained endurance athletes" (Waggener. 2016), is accurate, even if the time between the ingestion of the glucose solution and the actual high intensity work is so long that the "high GI carb bashing) would have you expect the athletes to fall into a hypoglycemic coma ;-)

What? Oh, yes! It would certainly be nice to see this being repeated with different types of exercises or athletes, but with the recreationally trained cyclists with a rather wide range of relative VO2 max values, the subjects in the study at hand are more representative of the average fitness enthusiast than pro-athletes or noobs | Comment on FB!

References:

• Kirwan, John P., et al. "Effects of moderate and high glycemic index meals on metabolism and exercise performance." Metabolism 50.7 (2001): 849-855.
• Waggener, Green T., et al. "The Effect of a Low Glycemic vs. High Glycemic Pre-Exercise Meal in Recreationally Trained Endurance Cyclists." (2016).

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).

First Study to Demonstrate Ergogenic Effects of Metformin - 14% Increased Time to Exhaustion in Standardized Supra-Maximal Cycling Test With 500mg of Ordinary Metformin

First Study to Demonstrate Ergogenic Effects of Metformin - 14% Increased Time to Exhaustion in Standardized Supra-Maximal Cycling Test With 500mg of Ordinary Metformin

AMPK cycling doping endurance metformin performance time to exhaustion

With the publication of Learsi's latest paper the list of things metformin can do for you has just gotten been expanded with another item: Doping!

You will probably remember my article about the potential, but unproven ergogenic effects of AMPK mimetics (read it). Well, as it is often the case, a new study is released only days after you've published a review of the existing literature. Oftentimes that's not really relevant, but in the case of the latest study from the Federal University of Alagoas this may be different. After all, we are dealing with a human study in  ten healthy, physically active, but non-athletic subjects with a mean (±SD) maximal oxygen uptake (VO2max) o 38.6 ± 4.5 mL/kg per min who performed (i) an incremental test; (ii) six submaximal constant workload tests at 40%-90% V O2max; and (iii) two supramaximal tests (110% V O2max).

All tests were performed twice once with a placebo supplement and once with 500mg of metformin. Both, the placebo and the metformin supplement were ingested 60 minutes before the supramaximal test, in order to investigate the hypothesis that metformin would increase anaerobic capacity and performance during high-intensity, short-duration exercise.

Like antioxidants metformin could blunt the hormetic response & long-term(!) adaptation

Is Vitamin E Good for the Sedentary Slob, Only?

Even Ice-Baths Impair the Adapt. Process

Vit C+E Impair Muscle Gains in Older Men

C+E Useless or Detrimental for Healthy People

Vitamin C and Glucose Management?

Antiox. & Health Benefits Don't Correlate

The authors, Learsi et al. (2015), based this hypothesis on the fact that metformin inhibits aerobic pathway energy production and so the glycolytic energy system could be overloaded during ATP production for muscle contraction.

Figure 1: Overview of the study design. The active / placebo treatment, i.e. 500mg of metformin or an identically looking placebo were administered 60 min before the supramaximal tests. The whole procedure was repeated twice, with at least 72h between the first and the second testing session (Learsi. 2015).

The aim was thus to to determine the effects of metformin on anaerobic capacity and to elucidate whether metformin has any ergogenic effect in intense, short-duration exercise in healthy, physically active men.

Is this really the first study? Yes, it is the first to prove metformin's ergogenic effects in humans. It's yet not the first human study to test the ergogenic effects of metformin. 2008 Johnson et al. made the mistake to assume that taking metformin would affect the VO2max, or ventilatory threshold. Just like Gudat et al. before them, Johnson et al. simply missed the most straight forward practical measure of exercise performance, i.e. total time to exhaustion, while focusing on things like VO2 (Johnson et al. 2008) or lactate (Gudat et al. 1997) which are nice to explain increases in performance, but - if we are honest - still irrelevant, when all that really counts is how fast you run, how long you cycle or how hard you hit.

While many of the variables they assessed didn't change, the already hinted at 14% increase in maximal endurance (see headline) is something that may make the difference between winning an Olympic medal and placing fourth or worse.

Figure 2: Changes in time to exhaustion and EPOC, both stat. significantly w/ metformin (Learsi. 2015).

What is also noteworthy is that the subjects excess post-exercise energy consumption, which was measured for (unfortunately) only 10 min, increased significantly, as well (see Figure 2, right). In contrast to what some bro-scientists may tell you that does not necessarily equal increased fat loss, but it's still interesting, because it may suggest that metformin improved the subjects' performance by increasing the supply of energy via the anaerobic alactic system, i.e. by boosting the efficacy of non-glucose- and thus non-lactic-acid-dependent energy pathways - in short: fat oxidation.

Alpha Lipoic Acid, GABA, Taurine, Green Tea, Gooseberry & Fenugreek. Plus: Metformin the No.1 Drug? Supplements to Improve and Restore Insulin Sensitivity - Read the First Installment of This Series | read more

Bottom line: This is the first human study to confirm that the AMPK-booster and frequently prescribed diabetes drug can trigger statistically and practically relevant increases in endurance performance during a supra-maximal VO2 max test. If we assume that a similar performance increase occurs in trained athletes, the Learsi study makes taking a bunch of grandma's metformin pills before the next race quite attractive. For the WADA, however, it means that they will have to watch and test for yet another commonly prescribed and readily available medication. And last but not least, for the "wonder-drug" metformin, it is yet another area of application: athletic performance enhancement or as we usually call it "doping" | Comment on Facebook!

References:

• Gudat, U., G. Convent, and L. Heinemann. "Metformin and exercise: no additive effect on blood lactate levels in healthy volunteers." Diabetic medicine 14.2 (1997): 138-142.
• Johnson, S. T., et al. "Acute effect of metformin on exercise capacity in active males." Diabetes, Obesity and Metabolism 10.9 (2008): 747-754.
• Learsi, et al. "Metformin improves performance in high-intensity exercise, but not anaerobic capacity." in healthy male subjects." Clin Exp Pharmacol Physiol. 2015 Aug 7. doi: 10.1111/1440-1681.12474. [Epub ahead of print]