By Dr. Jeremy Girmann
Since the time when I first started lifting weights at a public gym as a young teenager, I have overheard countless conversations about party plans, after hours antics, and weekend escapes, often involving alcohol. It always seemed a bit bizarre to me that many of the people in the gym who seemed most desperate to achieve tangible results from their workouts were the very ones who most often found themselves in these conversations. At a young age, before I had even a rudimentary understanding of physiology, my intuition was that alcohol wasn’t likely to help them in reaching their goals.
I have many times since been asked about the specific affects of alcohol on muscle growth. Does it in fact impede progress? Can I have my cake and eat it too? (Or perhaps have my Corona and drink it too?)
I should start by saying that I intend to focus on some of the research related to alcohol’s affect on skeletal muscle. Some literature exists which suggests that very moderate alcohol consumption (particularly in the form of red wine) might provide a slight cardiovascular benefit, which is beyond the scope of this article.
Most simply net muscle growth is related to the amount of muscle that is built minus the amount that is broken down – protein synthesis minus proteolysis. A large number of factors influence synthesis and degradation, many of which are influenced by alcohol.
We’ll consider several.
An interesting article published in the journal Alcohol and Alcoholism reported the findings of a study in which ethanol was infused into the brains of rats while monitoring markers of protein synthesis and degradation in gastrocnemius muscles. This study was particularly unique in that it examined the affects of alcohol when it was elevated only in the central nervous system.
The results indicated that local elevation of alcohol within the brain alone is capable of inhibiting protein synthesis and increasing protein breakdown. This novel study suggested the presence of neurally mediated pathways through which elevated levels of alcohol can be sensed in the brain and associated signals transmitted peripherally to the muscle.
By binding to its target cellular receptor, insulin-like growth factor 1 is intimately involved in muscle cell hypertrophy, characteristically causing an increase in protein synthesis and putting the breaks on protein degradation. Several studies have however demonstrated that with chronic alcohol ingestion, the IGF-1 receptor can become chronically activated therefore leading to dysfunctional activity of downstream signals which can compromise the ability of IGF-1 to slow protein breakdown.
Similar to IGF-1, the anabolic hormone insulin has been shown to exhibit abnormal signaling after ethanol ingestion. This has the potential to disrupt intracellular enzymatic processes and impair inhibition of proteolysis.
Testosterone and Growth Hormone
In a study of eight healthy males between the ages of 20 and 26 years, the effect of acute alcohol ingestion was studied on pulsatile secretion of multiple hormones. Ethanol ingestion was found to decrease serum testosterone concentration by 23% for up to 16 hours after the study subjects began drinking and the nightly rise in growth hormone was also found to be significantly blunted. It is thought that the decrease in testosterone levels is related to both synthesis inhibition and release of the hormone by the testes. Chronic alcohol ingestion has also been shown to suppress testosterone levels via its direct actions as a testicular toxin.
The stress hormone cortisol is known to accelerate the breakdown of muscle proteins. While an acute and transient increase in cortisol is a normal and important occurrence during periods of exercise, aberrant or excessive cortisol release can be problematic. Alcohol consumption has been shown to increase serum cortisol levels though it is unknown whether this increase is related to a stress response that occurs with alcohol ingestion or whether it is related to altered function of adrenocorticotropic hormone (ACTH), which is normally responsible for modulating cortisol release.
Also known as growth differentiation factor 8, myostatin is a protein that inhibits growth of the muscle cells in which it is produced. Have you ever seen pictures of heavily muscles Whippet dogs or Belgian Blue cattle floating around online? These represent examples of genetic mutations which led to reduced or absent production of myostatin, resulting in uninhibited muscular growth.
In one study of alcohol-fed rats, myostatin levels were found to be elevated more than twofold compared to the levels measured in control rats.
A night at the bar is unlikely to be followed by deeply restful and restorative sleep. In fact, alcohol has been shown to significantly reduce the rapid eye movement (REM) phase of sleep. Given that sleep is prime time for activation of the muscle-building machinery, compromised sleep quality can result in compromised muscle recovery and growth. In addition, a night of drinking and poor sleep certainly doesn’t prepare the body optimally for the following day. In fact, I recently treated an individual for rhabdomyolysis (rapid muscle breakdown) following a workout that he performed the day after one such night.
While there is certainly more to the sobering story, it is important to note that consideration of quantity is key. As with many things, the dose makes the poison. That being said, if maximizing and maintaining hard-earned muscle is your goal, you’d best stick to the barbell rather than the bar.