Hormones are chemical messengers that coordinate many functions within the body. Hormones control four major areas of body function: production, use, and storage of energy; reproduction; maintenance of the internal environment; and growth and development (1). For optimal hormonal function, the amount and timing of release must be finely coordinated, and a target tissues must respond to them accurately. It’s known that ethanol can impair the functions of hormone-releasing glands and the target tissues, thus causing medical consequences (2).
Excessive alcohol consumption impairs glucose metabolism (3). In addition, ethanol consumption stimulates hormones (aldosterone and glucocorticoids) which affect skeletal muscle metabolism (4). Understanding how hormones are affected from excessive alcohol is important to comprehend how muscle hypertrophy could get impaired. We’ll take a look at the current knowledge on the interactions between alcohol consumption and related hormonal alterations that may alter muscle hypertrophy.
Alcohol effects on protein synthesis and muscle growth
- Alcohol affects the type II (especially type IIx) muscle fibers, which are more responsive to hypertrophy (5).
- A decrease of 15-20% in basal protein synthesis was observed in skeletal muscle after 24hr of ethanol intoxication (6).
- Alcohol compromised the ability of insulin and insulin-like growth factor-1 (IGF-1) to slow proteolysis (6). Basically this means that alcohol negatively affected two hormones’ ability to slow muscle breakdown.
Alcohol effects on hormones
Hormones influence muscle hypertrophy and the hormonal profile is crucial in determining whether the outcome is protein synthesis or protein degradation.
- High doses of alcohol (1.5 g/kg bodyweight) shown to suppress testosterone by 20-25% after acute ingestion.
- Acute intake of alcohol of about 1.5 g/kg suppresses production of testosterone within an hour by decreasing luteinizing hormone release through the pituitary gland.
- A study demonstrated that during a recovery period from heavy resistance exercise, post exercise alcohol ingestion affected the hormonal profile including testosterone concentrations and bioavailability (7).
- Numerous studies have highlighted the decrease in testosterone after ethanol consumption (8-10).
The major findings in literature are that there is a dose dependency in the hormonal response. A lower dose of alcohol of less than 1.5 g/kg bodyweight show an increase in circulating levels of testosterone whereas higher dosages above 1.5 g/kg bodyweight show a decrease. It also seems that this decrease occurs in men while an increase is shown in women (11).
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2. Wolszczak B, Zasimowicz E, Juchniewicz J. [The effect of ethanol on the endocrynic system]. Pol Merkur Lekarski. Jan 2014;36(211):45-47.
3. Siler SQ, Neese RA, Christiansen MP, Hellerstein MK. The inhibition of gluconeogenesis following alcohol in humans. The American journal of physiology. Nov 1998;275(5 Pt 1):E897-907.
4. Reichman ME, Judd JT, Longcope C, et al. Effects of alcohol consumption on plasma and urinary hormone concentrations in premenopausal women. Journal of the National Cancer Institute. May 5 1993;85(9):722-727.
5. Andersen JL, Aagaard P. Myosin heavy chain IIX overshoot in human skeletal muscle. Muscle & nerve. Jul 2000;23(7):1095-1104.
6. Hong-Brown LQ, Frost RA, Lang CH. Alcohol impairs protein synthesis and degradation in cultured skeletal muscle cells. Alcoholism, clinical and experimental research. Sep 2001;25(9):1373-1382.
7. Vingren JL, Hill DW, Buddhadev H, Duplanty A. Postresistance exercise ethanol ingestion and acute testosterone bioavailability. Medicine and science in sports and exercise. Sep 2013;45(9):1825-1832.
8. Kumar V, Atherton P, Smith K, Rennie MJ. Human muscle protein synthesis and breakdown during and after exercise. Journal of applied physiology. Jun 2009;106(6):2026-2039.
9. Rivier C. Alcohol rapidly lowers plasma testosterone levels in the rat: evidence that a neural brain-gonadal pathway may be important for decreased testicular responsiveness to gonadotropin. Alcoholism, clinical and experimental research. Jan 1999;23(1):38-45.
10. Selvage DJ, Hales DB, Rivier CL. Comparison between the influence of the systemic and central injection of alcohol on Leydig cell activity. Alcoholism, clinical and experimental research. Mar 2004;28(3):480-488.
11. Bianco A, Thomas E, Pomara F, et al. Alcohol consumption and hormonal alterations related to muscle hypertrophy: a review. Nutrition & metabolism. 2014;11:26.