HMB for Every, Not Just Strength Athletes? Lower Body Fat, Improved VO2, Muscle, Testosterone in 2x12 Week Study

Lean muscle for athletes? HMB could help, irrespective of exercise type - by increasing strength, lean mass and VO2. In the study at hand, all three increased and that is / was in highly trained athletes.

You've read all articles about HMB at the SuppVersity? In that case you will be aware that HMB has hitherto been perceived rather as a strength / bodybuilding than an endurance supplement. Against that background it may come as a surprise that researchers from the Poznán University of Life Sciences in Poland chose to study the effects of HMB on the aerobic capacity (Burkalec-Michalski. 2016), instead of the usual study outcome, the subjects' strength. Is that a bad thing? Not at all!

After all, there are  more sports that require optimal aerobic performance than sports that require (only) optimal strength performance. It thus makes perfect sense that Krzysztof Durkalec-Michalski and Jan Jeszka chose aerobic performance as their primary, but not only study outcome.
Don't worry, though! With the body composition (unfortunately only BIA data) as second outcome measure, the results the scientists derived in an experiment that involved 58 male athletes aged 22 ± 6 years, with body weight of 82.9 ± 12.3 kg and height of 181 ± 7 cm, practicing wrestling (n = 12), judo (n = 10), Brazilian jiu-jitsu (n = 14), karate (n = 6), and rowing (n = 16) are still interesting and relevant for those of you who don't care that their aerobic conditioning forces them to take the elevator.

The subjects were asked to complete dietary records every second week to ensure that they did not change their dietary habits during the two 12-week supplementation periods during which the subjects alternately consumed HMB or a placebo supplement (for 12 weeks each with 10 days wash-out inbetween).

"The experiments were conducted using a preparation of calcium salt of β-hydroxy-β- methylbutyric acid, produced by Olimp Laboratories. A single capsule contained 1250 mg Ca-HMB, which corresponds to 1000 mg β-hydroxy-β-methylbutyrate. The producer also prepared a placebo preparation containing maltodextrin. The tested group of athletes was administered 3 capsules of the assigned preparation a day, in 3 doses as follows: upon waking, immediately after training, and before sleep. On nontraining days, the participants were instructed to consume one serving with each of three separate meals throughout the day" (Burkalec-Michalski. 2016 | my emphasis).

As you will remember based on previous SuppVersity articles, the HMB dose of 3g per day (in 3x1g doses) is what previous studies have shown to trigger significant improvements in performance and body composition in even shorter times-spans (Nissen. 1996; Lamboley. 2007; Wilson. 2008; Portal. 2011; Zanchi. 2011).
In conjunction with the previously not mentioned blood draws, the weighing and BIA measurements, as well as the ergometer tests that were performed at the beginning and end each of the 12-week study periods clearly support the scientists conclusion that...

"[t]he results indicate that supplying HMB promotes advantageous changes in body composition and stimulates an increase in aerobic capacity, while seeming not to significantly affect the levels of the analyzed blood markers" (Burkalec-Michalski. 2016).

Here, the scientists refer to the observed beneficial effects on fat-free mass (+0.2 kg HMB vs. -1.0 kg PLA, P = 0.021), with a simultaneous reduction of fat mass (-0.8 kg HMB vs. +0.8 kg PLA, P < 0.001), as well as the augmented increases in maximal oxygen uptake (VO2max: +0.102 L·min-1 HMB vs. -0.063 L·min-1 PLA, P = 0.013), time to reach ventilatory threshold (TVT: +1.0 min HMB vs. -0.4 min PLA, P < 0.0001), and the threshold load and heart rate at ventilatory threshold (WVT: +20 WHMB vs. -7 WPLA, P = 0.001 // HRVT: +8 bpm HMB vs. -1 bpm PLA, P < 0.0001).

Figure 1: HMB supplementation lead to sign. improvements in body composition (BIA | Burkalec-Michalski. 2016)

If and to which extent these effects were related to statistically significant increase in testosterone levels (P = 0.047), which, in contrast to the increase in cortisol, occurred only in the HMB group, is difficult to say (see Figure 1).

Figure 2: Changes in testosterone and cortisol during the treatment phase; * p < 0.05 (Burkalec-Michalski. 2016).

In view of the fact that the testosterone to cortisol ratio did not differ significantly in the two groups, it is yet very unlikely that the hormonal changes played a decisive role in terms of the previously discussed study outcomes.
References:

• Durkalec-Michalski, Krzysztof, and Jan Jeszka. "The Effect Of Hmb On Aerobic Capacity And Body Composition In Trained Athletes." The Journal of Strength & Conditioning Research (2016).
• Lamboley, Cédric RH, Donald Royer, and Isabelle J. Dionne. "Effects of beta-hydroxy-beta-methylbutyrate on aerobic-performance components and body composition in college students." International journal of sport nutrition and exercise metabolism 17.1 (2007): 56.
• Nissen, S., et al. "Effect of leucine metabolite β-hydroxy-β-methylbutyrate on muscle metabolism during resistance-exercise training." Journal of Applied Physiology 81.5 (1996): 2095-2104.
• Portal, Shawn, et al. "The effect of HMB supplementation on body composition, fitness, hormonal and inflammatory mediators in elite adolescent volleyball players: a prospective randomized, double-blind, placebo-controlled study." European journal of applied physiology 111.9 (2011): 2261-2269.
• Wilson, Gabriel J., Jacob M. Wilson, and Anssi H. Manninen. "Effects of beta-hydroxy-beta-methylbutyrate (HMB) on exercise performance and body composition across varying levels of age, sex, and training experience: A review." Nutrition & metabolism 5.1 (2008): 1.
• Zanchi, Nelo Eidy, et al. "HMB supplementation: clinical and athletic performance-related effects and mechanisms of action." Amino acids 40.4 (2011): 1015-1025.