Tuesday, August 4, 2015

HMB For Endurance Athletes: 3g Regular HMB Make Elite Rowers Run Out of Breath 10% Later + Facilitate Fat Loss

HIIT on the rowing machine is a powerful fat loss tool even w/out HMB. It's yet also pretty intense, so I'd suggest that you don't do it everyday | learn more
You will probably remember Jacob Wilson's impressive 2014 HMB study (Wilson. 2014 | read more). A study that repopularized an old supplement that was once marketed as being "as potent as a weak steroid". Steroids, however, are not exactly the #1 doping agent for endurance athletes. While many (ab)use everything that could improve their performance, agents like erythropoietin (EPO) are obviously much more popular.

Against that background it is not totally obvious to do what Krzysztof Durkalec-Michalski and Jan Jeszka did in their latest study: To assess the effect of HMB supplementation on physical capacity, body composition and levels of biochemical markers in endurance athletes, elite rowers to be precise.
Learn more about the potential beneficial effects of HMB at the SuppVersity:

HMB For Fat Loss?

Hica & HMB in Yogurt

More on HMB Free Acid

Breakthrough HMB Science

HMB + Whey = Useless?!

HMB Hampers Fat Loss?
The study design was simple, yet effective: 16 elite male rowers, aged 20± 2 years, with a body weight of 87.3 ± 9.8 kg and a height of 187 ± 5 cm consumed 3×1 g HMB/day or an identically looking placebo for 2×12 weeks. "2×12"? Yes, the study wasn't just randomized, placebo controlled, and double-blinded, it was also a crossover study with a 10 days washout period between the first and the second 12 week period. This makes the results more reliable - in spite of the low number of subjects.
Figure 1: Overview of the design of this double-blind, randomized, controlled crossover trial (Durkalec-Michalsky. 2015)
Before and after the two 12-week phases, aerobic (maximal oxygen uptake, ventilatory threshold) and anaerobic (anaerobic power indices) capacity were determined and analyses of the body composition as well as levels the creatine kinase, lactate dehydrogenase, testosterone (T), cortisol (C) levels and the T/C ratio were conducted.
Figure 2: While it looks like there was a sign. testosterone (T) boost in the HMB group, the p-value is 0.569. Accordingly, only the fat mass changes showed sign. inter-group differences (Durkalec-Michalsky. 2015).
What the analyses of these data revealed was quite conclusive: The provision of "regular" calcium HMB at a dosage of "only" 3g/day had a highly significant "advantageous effecton the increase in aerobic capacity and the reduction of fat mass" (Durkalec-Michalsky. 2015). More specifically,...
  • Figure 3: Changes in maximal oxygen uptake and rates at ventilatory threshold after 12-week supplementation of HMB. Values are expressed as mean ± SD. Significant differences compared with placebo (independent samples t-tests) at: *- p = 0.03; †- p = 0.012, ‡- p = 0.002; #- p < 0.001. VO _ 2 max: maximal oxygen uptake; TVT: time to VT; WVT: load at VT; HRVT: HR at VT (Durkalec-Michalsky. 2015).
    the subjects' VO2 max increased (+2.7 mL/min/kg) significantly (p < 0.001) in comparison to PLA where it was even slightly reduced (−1.0 mL/min/kg), 
  • the ventilatory threshold, the threshold load, and the heart rat, which are the time-point, wattage, and heart rate at which further increases in respiration will no longer lead to increases in VO2 intake, were postponed by +1.2 min, +0.42 W, and +9bpm, respectively,
  • with -0.9 kg the subjects in the HMB group lost body fat, while the subjects in the PLA groups gained 0.8 kg (p = 0.03), and lastly
  • the refusal time to continue (a proxy of short term recovery) in the progressive test was extended (p = 0.04), maximum load (p = 0.04) and anaerobic peak power (p = 0.02) increased. 
What is interesting is that all these benefits occurred in the absence of changes in anaerobic adaptation or blood marker levels. This is cool, but it's also a problem, because as long as we don't know the mechanisms, it's hard to predict (a) who would benefit (most), (b) which supplements would act as synergists and (c) which supplements work via the same pathways so that taking them would make the use of HMB obsolete.
Breakthrough HMB Research: Additional(!) 10% Reduction in Body Fat, 5% Higher Lean Mass + 2x Higher Strength Gains After 12W of Heavy Lifting in Trained Individuals | more
So what do we make of the results? There's little doubt that Durkalec-Michalsky's latest study confirms that HMB can be useful not only for resistance trainees or sprinters, but also for athletes who are competing in sports with an endurance focus. Furthermore, it is yet another (non-sponsored) study to prove that it does not take the expensive free-acid form of HMB to see results.

What the study doesn't tell us, though, is whether the effects would remain significant if the subjects had been on the "athlete standard stack" consisting of creatine and whey protein. In view of the fact that there's no way to tell what mediated the VO2 and power improvements, it's also impossible to judge how likely it is that the co-ingestion of the aforementioned supps would marginalize the benefits.

So what? While it may be worth trying HMB, future studies with a focus on the mechanisms and the interactions with other supplements are still warranted | Comment on Facebook!

  • Durkalec-Michalski, Krzysztof, and Jan Jeszka. "The efficacy of a β-hydroxy-β-methylbutyrate supplementation on physical capacity, body composition and biochemical markers in elite rowers: a randomised, double-blind, placebo-controlled crossover study." Journal of the International Society of Sports Nutrition 12.1 (2015): 1-11.
  • Wilson, Gabriel J., et al. "The effects of 12 weeks of beta-hydroxy-beta-methylbutyrate free acid supplementation on muscle mass, strength, and power in resistance-trained individuals: a randomized, double-blind, placebo-controlled study." European Journal of Applied Physiology (2014)