ALCOHOL & ENDURANCE ATHLETES

A research review of alcohol’s impact on recovery and performance.

By Jennifer A. Kurtz, PhD, CSCS, CISSN, EP-C

INTRODUCTION

Alcohol consumption and athletic performance often make for a complex relationship. For endurance athletes, who rely on optimal recovery, metabolism, and hydration, alcohol can significantly impact these processes. This blog delves into what science tells us about alcohol’s effects on endurance performance and recovery, offering insights backed by peer-reviewed research.

ALCOHOL AND ATHLETIC RECOVERY

Recovery is a cornerstone of endurance training, as it allows the body to repair and adapt to the stress of prolonged activity. Unsurprisingly, alcohol consumption impairs recovery in several ways.

Inflammation and Muscle Recovery

Alcohol impairs endurance performance by increasing systemic inflammation and inhibiting post-exercise muscle recovery processes. Acute alcohol consumption elevates pro-inflammatory cytokines, such as IL-6 and TNF-α, which one study shows can delay muscle repair and adaptation after exercise (Barnes et al., 2010).

In that same study, acute alcohol consumption after resistance exercise was shown to impair muscle protein synthesis (MPS), a critical process for muscle repair and adaptation (Barnes et al., 2010). Another study found that this MPS reduction occurs when alcohol disrupts mTOR signaling, a critical pathway for tissue repair and growth (Parr et al., 2014), ultimately compromising recovery and subsequent endurance performance.

Although endurance athletes rely less on MPS than strength athletes, the delay in recovery may still impact subsequent training sessions. Athletes should minimize excessive alcohol consumption post-exercise to prevent inflammation and ensure optimal MPS.

Glycogen Replenishment

Alcohol can interfere with glycogen resynthesis by prioritizing its own metabolism over glucose storage, as the body perceives alcohol as a toxin. This competition for metabolic pathways slows down glycogen replenishment, especially when combined with inadequate carbohydrate intake (Burke, 1997).

When alcohol is consumed after exercise, its metabolism becomes a priority due to its toxic nature, diverting key metabolic resources away from glycogen synthesis (Paik et al., 2018). This process reduces the efficiency of glucose uptake into the liver and muscles, further slowing glycogen replenishment and delaying recovery.

Studies show that alcohol consumption combined with inadequate carbohydrate intake exacerbates this effect, leading to prolonged recovery times. For example, alcohol consumption after glycogen-depleting exercise (maximal exercise) reduced glycogen resynthesis rates by up to 50% compared to carbohydrate-matched conditions (Burke et al., 2003). This reduction can impair subsequent endurance performance by leaving athletes under-fueled for their next session.

Additionally, alcohol may inhibit insulin signaling, which is critical for glucose transport into cells and glycogen storage. Post-exercise alcohol ingestion decreased insulin sensitivity in skeletal muscle, further compounding the delay in glycogen replenishment (Burke et al., 2003). Alcohol consumption should be carefully managed in the recovery period, particularly in endurance athletes reliant on rapid glycogen restoration.

Hydration and Electrolyte Balance

Alcohol increases urine output by suppressing the release of antidiuretic hormone (ADH), leading to heightened fluid loss even when the body is already in a dehydrated state from exercise (Wijnen et al., 2016, Vella & Cameron-Smith, 2010). This compounded dehydration can impair cardiovascular function, reducing blood volume and limiting oxygen delivery to working muscles, which is critical for endurance athletes during recovery.

Additionally, dehydration negatively affects thermoregulation, impairing the body’s ability to dissipate heat effectively. Post-exercise alcohol consumption exacerbated heat retention, particularly in endurance athletes training or competing in hot environments, increasing the risk of heat-related illnesses (Morris et al., 2024).

Alcohol consumption also delays rehydration by inhibiting electrolyte replenishment and reducing plasma volume restoration. A study by Carrigan, et al. (2021) showed that consuming beverages with even moderate alcohol content (4% ABV) after endurance exercise resulted in significantly lower rates of fluid retention compared to non-alcoholic fluids, further delaying recovery and potentially impairing subsequent performance (Wijnen et al., 2016). It is critical to prioritize rehydration with non-alcoholic, electrolyte-rich fluids after endurance events to optimize recovery and sustain performance.

ALCOHOL’S ACUTE EFFECTS ON PERFORMANCE

The acute consumption of alcohol – such as having drinks the night before or shortly before a race – can negatively influence endurance performance. Alcohol detrimentally affects cardiovascular efficiency, neuromuscular coordination, and energy metabolism, thereby impairing exercise performance and increasing the risk of injury. Athletes should be cautious about alcohol consumption to maintain optimal health and performance levels.

Decreased Cardiovascular Efficiency

Alcohol disrupts the nervous system’s control of heart rate and blood pressure, leading to decreased cardiovascular efficiency. Alcohol consumption can significantly impair exercise performance by reducing endurance and increasing fatigue (Barnes, 2014). Additionally, alcohol consumption can negatively alter normal immunoendocrine function, blood flow, and protein synthesis, further impairing recovery from skeletal muscle injury (Barnes, 2014).

Neuromuscular Coordination

Alcohol impairs motor skills, coordination, and cognitive function, increasing the risk of injury during training or competition (Siekaniec, 2017). For endurance athletes on technical trails or cycling routes, alcohol's effects on reaction time and muscle strength can be especially hazardous, as it impairs quick decision-making and precise movements (Vella & Cameron-Smith, 2010). Furthermore, alcohol disrupts recovery by hindering muscle repair and glycogen replenishment, further increasing the risk of injury during subsequent activities (Vella & Cameron-Smith, 2010).

Energy Metabolism

Alcohol inhibits fat oxidation, an essential energy source during prolonged activity. This metabolic shift forces reliance on limited glycogen stores, leading to an earlier onset of fatigue (Rapoport, 2010). It goes without saying, but glycogen depletion negatively affects endurance exercise performance (Knuiman et al., 2015). This underscores the critical role of maintaining sufficient glycogen levels to support optimal endurance performance.

CHRONIC ALCOHOL USE AND LONG-TERM PERFORMANCE

For athletes who regularly consume alcohol, the long-term implications can be even more pronounced. Excessive alcohol consumption negatively affects endurance performance by increasing body fat, disrupting hormonal balance, and impairing immune function. Therefore, athletes should moderate their alcohol intake to support optimal performance and overall health.

Body Composition

Excessive alcohol consumption can severely undermine athletic performance by increasing body fat and impairing essential physiological functions. Alcohol is calorie-dense, providing 7 kcal/gram with little nutritional value. Excessive intake contributes to increased body fat, which can hinder endurance performance by reducing the power-to-weight ratio (Siekaniec, 2017).

This increase in body fat can lead to decreased agility and increased energy expenditure during physical activities, further impairing performance (Barnes, 2014). Additionally, higher body fat levels can negatively affect thermoregulation, making it harder for athletes to maintain optimal body temperature during exercise (Barnes, 2014).

Hormonal Disruptions

Chronic alcohol use lowers testosterone levels in men and disrupts estrogen balance in women. Both hormones are vital for muscle repair, bone health, and overall athletic performance (Smith et al., 2023).

Reduced testosterone levels in men can lead to decreased muscle mass and strength, negatively impacting athletic performance. In women, alcohol-induced estrogen imbalance can result in irregular menstrual cycles and decreased bone density, further compromising athletic performance (Gill, 2000).

Immune Function

Endurance athletes already experience temporary immune suppression post-exercise. Alcohol exacerbates this by reducing the activity of immune cells, increasing the risk of infections (Drummond & Greenfield, 2001). Consequently, endurance athletes must be particularly cautious with alcohol consumption to avoid compromising their immune health and recovery.

Chronic alcohol consumption impairs both innate and adaptive immune responses, leading to decreased inflammatory responses and altered cytokine production (Szabo & Saha, 2015). This immune dysfunction can result in increased susceptibility to infections and prolonged recovery times (Szabo & Saha, 2015).

MODERATION IS KEY

While the evidence paints a cautionary tale, occasional, moderate alcohol consumption is unlikely to derail an athlete’s performance. The key lies in timing and quantity.

• Post-Event Timing: Wait until rehydration and glycogen stores are replenished before consuming alcohol.
• Moderation: Limit intake to minimize its diuretic and metabolic effects. The World Health Organization defines moderate drinking as up to one standard drink per day for women and two for men.
• Balanced Diet: Pair alcohol with a nutrient-dense meal to mitigate its impact on recovery and metabolism.

CONCLUSION

For endurance athletes, alcohol can hinder performance and recovery through its effects on metabolism, hydration, and muscle repair. While occasional moderate consumption may not significantly impair long-term goals, consistent or excessive drinking poses clear risks to endurance performance.

Athletes should weigh the potential consequences and align their alcohol consumption with their training and performance objectives. A mindful approach to alcohol can help ensure it doesn’t undermine the countless hours of training invested in endurance success.

REFERENCES

• Barnes, M. J., Mündel, T., & Stannard, S. R. (2010). Acute alcohol consumption aggravates the decline in muscle performance following strenuous eccentric exercise. Journal of Science and Medicine in Sport, 13(2), 189–193.
• Barnes, M. J. (2014). Alcohol: impact on sports performance and recovery in male athletes. Sports Medicine, 44(7), 909-919.
• Burke, L. M. (1997). Nutrition for post-exercise recovery. Australian journal of science and medicine in sport, 29(1), 3-10.
• Burke, L. M., Collier, G. R., Broad, E. M., Davis, P. G., Martin, D. T., Sanigorski, A. J., & Hargreaves, M. (2003). Effect of alcohol intake on muscle glycogen storage after prolonged exercise. Journal of Applied Physiology, 95(3), 983-990.
• Drummond, C., & Greenfield, A. (2001). Alcohol and the immune system. Alcoholism, 1-2.
• Eisenhofer, G., et al. (1995). Influence of alcohol on maximal oxygen uptake. European Journal of Applied Physiology, 71(3), 277-280.
• Fitzgerald, L., et al. (2001). Impact of alcohol on immune function in athletes. Exercise Immunology Review, 7, 13-32.
• Gill, J. A. N. (2000). The effects of moderate alcohol consumption on female hormone levels and reproductive function. Alcohol and alcoholism, 35(5), 417-423.
• Knuiman, P., Hopman, M. T., & Mensink, M. (2015). Glycogen availability and skeletal muscle adaptations with endurance and resistance exercise. Nutrition & metabolism, 12, 1-11.
• Kokavec, A., et al. (2008). Alcohol impairs fat oxidation and energy metabolism. Alcohol and Alcoholism, 43(2), 163-168.
• Maughan, R. J. (2006). Alcohol and athletic performance. Nutrition, 22(9), 852-853.
• Morris, N. B., Ravanelli, N., & Chaseling, G. K. (2024). The effect of alcohol consumption on human physiological and perceptual responses to heat stress: a systematic scoping review. Environmental Health, 23(1), 73.
• Parr, E. B., Camera, D. M., Areta, J. L., Burke, L. M., Phillips, S. M., Hawley, J. A., & Coffey, V. G. (2014). Alcohol ingestion impairs maximal post-exercise rates of myofibrillar protein synthesis following a single bout of concurrent training. PLoS One, 9(2), e88384.
• Rapoport, B. I. (2010). Metabolic factors limiting performance in marathon runners. PLoS computational biology, 6(10), e1000960.
• Siekaniec, C. (2017). The effects of alcohol on athletic performance. NSCA Coach, 3(4).
• Suter, P. M. (2005). Effects of alcohol on body weight and body composition. Physiology & Behavior, 86(5), 640–646.
• Szabo, G., & Saha, B. (2015). Alcohol’s effect on host defense. Alcohol research: current reviews, 37(2), 159.
• Vella, L. D., & Cameron-Smith, D. (2010). Alcohol, athletic performance and recovery. Nutrients, 2(8), 781-789.
• Vingren, J. L., et al. (2013). Hormonal responses to alcohol in men and women. Alcoholism: Clinical and Experimental Research, 37(3), 391–397.
• Wijnen, A. H., Steennis, J., Catoire, M., Wardenaar, F. C., & Mensink, M. (2016). Post-exercise rehydration: effect of consumption of beer with varying alcohol content on fluid balance after mild dehydration. Frontiers in nutrition, 3, 216691.