Purpose: Several studies have reported that β-hydroxy-β-methylbutyrate (HMB) has beneficial effects on exercise-induced muscle damage (EIMD). Here, we examine the effects and mechanisms of HMB supplementation on exercise-induced muscle damage EIMD and provide guidelines for the application of supplementary HMB.
Methods: For this review, we performed web searches using PubMed, Web of Science, and Wiley Online Library. Keywords used were 'HMB,' 'HMB and EIMD,' 'HMB and recovery,' 'HMB and resistance exercise,' and 'HMB and eccentric muscle contraction.'
Results: Several previous studies have shown that HMB supplementation can reduce EIMD and promote recovery. In particular, reductions were detected in certain markers of muscle membrane damage, including creatine kinase and lactate dehydrogenase. There may be multiple mechanisms in which HMB supplementation reduces EIMD, including reducing muscle-damage-induced inflammation and oxidative stress and promoting cellular cholesterol synthesis by increasing the production of β-hydroxy-β-methylglutaryl-Co-A, a product of HMB metabolism. In general, the suggested daily intake of HMB is 3 g. In addition, the timing and duration of HMB intake can be classified as chronic [≥ 2 weeks, in which a total of 3 g is consumed daily (3 × 1 g taken at breakfast, lunch, and dinner)] or acute (taken 30-60 min before exercise). The timing of intake during exercise may vary depending upon whether the formulation is calcium HMB (60-120 min before exercise) or the free-acid form of HMB (30-60 min before exercise). Notably, the co-administration of HMB and creatine does not appear to be effective in reducing EIMD.
Conclusion: HMB supplementation can be considered as an effective nutritional strategy to minimize EIMD.
Keywords: muscle damage; nutritional supplement; recovery; resistance exercise; β-hydroxy-β-methylbutyrate.