HMB Grows Muscle Without Exercise


From Ergo Log


HMB can boost muscle strength and quality even if you don’t do strength training. Sports scientist Jeffrey Stout, of the University of Central Florida, draws this conclusion in a human study involving nearly fifty over 65s. The results of the study have been published in Experimental Gerontology.


HMB is a metabolite of leucine [left in the figure below]. Muscle cells crank up their anabolic machinery when supplied with large amounts of leucine – and part of the anabolic effect is probably due to HMB.


Sports scientists and anti-aging researchers are studying HMB in the hope that the compound can help reduce or reverse the loss of muscle mass in the elderly.


As humans are living longer and longer thanks to medical science, the number of elderly people who are losing so much muscle mass that they need help is also increasing. In the US, 30 percent of men and 64 percent of women over the age of 74 are no longer able to lift a weight of 4.5 kg. [Am J Public Health. 1981 Nov;71(11):1211-6.]


Stout wondered whether HMB can help maintain muscle strength in the over 65s, without them having to do weight training. He did a trial with just under 50 subjects, all over the age of 65. Their average age was in the early seventies.


Stout gave half of his subjects a placebo for 24 weeks. The other half was given 3 g HMB daily. They were given the traditional, calcium salt form of HMB [CaHMB].


In the 24 weeks that the subjects took HMB, their lean body mass increased by half a kilogram and their muscle mass by 300g. Both effects were statistically significant.



The researchers also measured the strength the subjects were able to develop when doing leg extensions [Extensor] and leg curls [Flexor] of 60 and 180 degrees. The table below shows that the HMB group became significantly stronger on a number of points.



The researchers did another experiment in which they got a comparable group of subjects to do weight training for 24 weeks. Half of this group were given a placebo, and the other half 3 g HMB per day. Both groups progressed, but the HMB group did slightly better than the placebo group.


This last experiment added more weight to the growing pile of evidence that strength training is good for the over 65s, the researchers believe. In their view all elderly people who notice they are losing muscle strength and mass should do some kind of resistance training.


“However, there are three potential limitations: 1) low adherence to high intensity resistance exercise programs, 2) discontinuation of resistance exercise will result in rapid loss of benefits, and 3) in frail elderly, resistance exercise may not be adequate to reverse loss of muscle function”, the researchers add as a cautionary note.


“Accordingly, non-exercise interventions (nutritional or pharmacological) that can improve body composition, muscle quality and functionality, are critically important”, they conclude. “The findings of the present pilot study indicate that CaHMB without resistance exercise enhances strength and muscle quality in elderly men and women, thereby supporting its potential as a nutritional intervention to prevent sarcopenia and its associated functional decline in people as they age.”


Abbot Nutrition funded the study and provided one of the researchers.



Exp Gerontol. 2013 Aug 24;48(11):1303-1310.



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