After working hard all week in the office and in the gym, many individuals choose to toast the weekend over a drink or two with friends. While a very common practice and certainly legal for adults over 21, this “happy hour” may have some unhappy side effects. In this article, we will delve into the effects of alcohol consumption on muscle synthesis, recovery, brain cognition, and sleep patterns. Read on to understand the ways in which alcohol might derail our best fitness efforts…and then some.
Alcohol and the Post-Exercise Recovery Process
As personal trainers, we often remind our clients to hydrate well after a tough workout, and to consume an adequate portion of lean protein along with some simple carbohydrates. All of this points to one’s best chances of a successful recovery from the taxing efforts accomplished in the gym.
In today’s busy world, we cannot seem to escape some of the bigger stressors we encounter on a regular basis: traffic, carpool schedules, back-to-back meetings and/or client sessions, etc. Another event that places a tremendous burden of stress on the human body is the post-workout recovery process, which most of us probably fail to consider. Among all of the aforementioned pressures, one of the unnecessary stressors during a recovery phase involves alcohol consumption.
Alcohol has the ability to permeate virtually every organ and tissue in the body; when taken to excess, this may result in tissue injury and/or organ dysfunction. Alcohol consumption leads to hormonal disturbances which, in turn, can disrupt the body’s physiological ability to maintain homeostasis. In terms of post -exercise recovery, acute alcohol ingestion reduces muscle protein synthesis after the workout ends, precisely that window of opportunity during which we hope the body moves into an anabolic state. We will discuss this process in further detail later on in the article.
The Interplay of Cortisol and Testosterone
Significant research has gone into understanding the delicate hormonal dance that occurs in the human body every moment of the day. Post-workout shifts in particular have garnered a tremendous amount of attention.
We know that cortisol levels generally increase following intense resistance training, while testosterone levels decrease. This natural phenomenon occurs even under the best of circumstances, but does not last long. The effects of alcohol consumption following a workout alter cortisol and testosterone levels even more. In one study. On average, the participants who consumed alcohol expressed higher levels of cortisol (a catabolic substance) and lower levels of testosterone (which fosters anabolism) in comparison to the control group. Decreased testosterone levels and increased cortisol levels indicate a significant shift in the anabolic-catabolic balance, which likely leads to reduced recovery capacity and, therefore, poor performance. When present in excessive levels, cortisol will eventually erode hard-earned lean body/muscle mass while simultaneously increasing energy expenditure.
Messing With Muscle Synthesis
Earlier, we alluded to the fact that alcohol consumption can have a negative impact on muscle synthesis, derailing the efforts of even the most dedicated weightlifters. The process, while complex, primarily involves suppressing phosphorylation and activation of the mTOR (mammalian target of rapamycin) pathway, a crucial kinase cascade. From a mechanical point of view, alcohol disrupts mTOR signaling –the molecular switch that tells muscles to grow – while also increasing oxidative stress and inflammation, further blunting the anabolic response. The body must therefore prioritize repairing the alcohol-induced damage, leaving less energy available to build strength in the gym. In the process, alcohol increases the expression of muscle-specific enzymes that are upregulated by conditions that promote skeletal muscle atrophy.
After a workout, the muscles crave protein; alcohol consumption can interfere with the manner in which the body processes protein. One research study revealed that alcohol consumed after resistance exercise can reduce the synthesis of protein in the muscles by as much as 37%. The ensuing oxidative stress coupled with inflammation further delays the healing of muscle tissues, revealing how the negative effects of post-exercise alcohol consumption may have long-term consequences on muscle health and growth.
Nutrient Absorption and Digestive Enzymes Take a Hit
In addition to protein, an athlete’s body must have the ability to absorb and utilize vitamins and minerals in order to repair itself optimally. Vitamin D, B-complex vitamins and zinc all play key roles in muscle function and repair. However, excessive alcohol consumption can affect this absorption, as well as potentially doubling the usual excretion rate of the nutrient magnesium.
Muscles may also suffer from impaired calcium absorption due to post-workout drinking. Alcohol disrupts calcium’s release from the sarcoplasmic reticulum, a highly specific structure consisting of an intricate network of tubules designed for regulating calcium homeostasis as it relates to muscle contraction. Fast-twitch muscle fibers in particular experience the greatest dysfunction, often eliciting soreness and delayed recovery after drinking alcohol. Since alcohol can irritate the lining of the stomach, especially when consumed without sufficient food, this irritation can reduce both the production and the activity of digestive enzymes, key factors in the body’s process of breaking down and absorbing nutrients.
Alcohol -Induced Dehydration Upsets Electrolyte Balance
Scientifically, we can categorize alcohol as a diuretic, defined as that which leads to the loss of fluids and electrolytes, both of which serve crucial roles in muscle function and repair. Consumption of alcoholic beverages suppresses the release of vasopressin, a hormone tasked with helping the kidneys reabsorb water, in an effort to prevent excessive urine production. With lower vasopressin levels, the kidneys produce more urine, accelerating fluid loss. According to Dr. Kathryn Boling, a physician from Lutherville, MD, dehydration has the potential to dangerously elevate heart rate, injure the cardiac muscle, and cause blood pressure to plummet, which in turn may elicit dizziness and/or fainting.
Human muscle tissue consists of approximately 75% water; therefore, even slight dehydration can significantly impair muscle function, often leading to cramps, strains, and other injuries. Water also plays a crucial role in transporting nutrients to muscle fibers, flushing toxins, preventing muscle soreness, and supporting overall metabolic processes. As we can understand, a lack of adequate hydration brought on by alcohol consumption can potentially thwart these essential functions, making muscle recovery even more challenging.
Beyond general dehydration, disrupting the body’s delicate electrolyte balance by combining alcohol with exercise creates a serious physiological challenge. Any alcohol consumed after a workout amplifies the electrolyte loss already caused by sweating. Alcohol-induced diuresis can lead to dangerous deficits in sodium and potassium levels; since the human heart functions in part on a sodium/potassium pump, any disruption severe enough can interfere with cardiac rhythm. Studies show that urine sodium and potassium levels significantly fluctuate over time after consuming alcoholic beverages post-exercise. As nutrient depletion couples with alcohol/dehydration, an athlete may begin to experience decreased muscle function as well as compromised nerve signaling.
Cognitive Function and Neuromuscular Coordination
Not every aspect of recovery from resistance training involves muscle synthesis and metabolic processes. Athletes could greatly benefit from an understanding of how alcohol consumption also impairs cognitive function during recovery. This comes into play particularly in team sports, which tend to involve key decision -making processes, speed, and quality of responses to visual stimuli.
In a similar manner, alcohol can have a detrimental effect on one’s coordination and motor skills, which paves the way for increases in injury rates both during training and potentially in the midst of a competitive event. Endurance athletes who rely on reaction time and muscular strength, such as cyclists or trail runners, must pay close attention to alcohol consumption as it has proven to slow one’s reaction response time, impairing necessary immediate decision-making and precise, specific movements. Injury risk gets further exacerbated when we consider how alcoholic beverages tend to interfere with glycogen replenishment, a key aspect of endurance training and recovery.
Alcohol, Sleep Cycles and Memory Formation
Most athletes and fitness professionals acknowledge the importance of adequate sleep for muscle recovery. During periods of rest, the body can repair and rebuild muscle fibers damaged by serious strength training and intense exercise. The body typically releases human growth hormone during periods of deep sleep; since this hormone primarily drives tissue growth and muscle fiber repair, serious athletes do their best not to disrupt their natural sleep patterns to maximize muscle health.
Even though a drink or two prior to bedtime may have a sedative effect on the body, alcohol does not guarantee a sound night’s rest. Paradoxically, while a night of drinking may invite fatigue, it greatly reduces the proportion of rapid eye movement (the REM sleep cycle). This important phase of the natural sleep cycle strongly aligns with mental recovery, mood regulation, and muscle repair.
Memory formation, a complex and lengthy process, often gets solidified while we sleep. When alcohol interferes with a good night’s rest by disrupting the sequence of our sleep cycles, it simultaneously reduces the brain’s ability to learn and retain new information. Even drinking up to six hours before heading to bed can negatively affect the sleep cycle.
Consider the athlete who plays on a college or professional football team. This sport requires a tremendous amount of time spent learning new plays. Any elite athlete knows that solid preparation can lead to optimal performance on the field. However, if the team goes out for drinks after a day of practice or new drills, the players fail to reap the full benefits of their efforts. Alcohol in their system compromises the brain’s hippocampus, the region vital to memory formation. Without the ability to form memories adequately, learning new information vital to the game suffers.
Hangovers
The majority of individuals can “sense” when intoxication wears off, when they feel less fatigued after a night of partying. However, even athletes can succumb to the lingering effects of a hangover, which can significantly derail their training and competitions.
The main effects of hangovers include electrolyte imbalance, hypoglycemia (low blood sugar levels), stomach upset/nausea, vasodilation, and sleep disturbances. These effects naturally lead to an array of other physical symptoms, many of which can render an athlete unable to train at normal capacity. Research has shown an approximate 11% decrease in aerobic capacity in individuals attempting to exercise while the body works through a hangover. The effects of a hangover on anaerobic performance remain unclear; however, we can say unequivocally that athletes training or competing without a hangover will most likely have a competitive edge over their still-recovering opponents.
Considerations
Everyone likes to celebrate after a big win. Doing so with friends in a party-like atmosphere seems commonplace today, especially among competitive and elite athletes. Before getting too caught up in overconsumption, however, we offer these cautionary tips:
- Consuming five or more alcoholic beverages in one night can affect mental and physical capacities for up to three days.
- Two consecutive nights of drinking five or more alcoholic beverages can have an effect that may linger for up to five days.
Of course, how alcohol affects an individual depends greatly on a multitude of variables such as body size/weight, prior food consumption, age, maintenance medications, and overall health, and it exceeds the scope of this article to quantify/suggest restrictions on alcohol consumption. Responsible athletes must decide for themselves, weighing the negative effects on their bodies against the fun of imbibing.
References
pmc.ncbi.nlm.nih.gov/articles/PMC3257708/
pmc.ncbi.nlm.nih.gov/articles/PMC7739274/
healthpromotion.ucsd.edu/topics/alcohol/nutrition-endurance.html
santabarbararecovery.com/how-does-alcohol-affect-recovery/
thevillatreatmentcenter.com/muscle-soreness-after-alcohol/
banburylodge.com/blog/substance-abuse/delayed-gains-exploring-how-alcohol-impacts-muscle-repair/
