By Candace Chemtob, B.S. and M.S. in Human Nutrition
Obviously athletic performance and alcohol don’t mix well. Performing under the influence of alcohol will reduce your ability to think clearly on the court, slow reaction times, reduce coordination, and worse, may increase the likelihood of injury. Remarkably, however, the effects of alcohol on performance are further reaching and could erase some of the physiologic gains that you may have derived from training or competition.
Alcohol (technical name: ethanol) disrupts carbohydrate and protein metabolism. These metabolic alterations not only have an immediate negative impact on athletic performance, but also prevent a full recovery. It would be hard to overstate the importance of recovery in achieving peak performance on the court. Improvements in strength and speed, plus ability to perform at a high level day after day, are dependent on recovery after training and competition.
To reach your maximal output, that is to perform at your best, your body needs to use the metabolic pathways that provide the most energy in the shortest amount of time. This is accomplished by utilizing carbohydrates as fuel, predominantly as glucose, during exercise. The amount of “fuel”, or glucose available during exercise, is determined by your blood glucose levels (glycogen stores), and complex interactions with other organ systems including the liver.
When blood glucose levels drop, you will feel fatigued and your performance level will drop rapidly. Low blood glucose levels trigger the release of fat from adipose tissue. Fat cannot provide energy fast enough to sustain the high intensity movements required in squash. Alcohol consumption suppresses hepatic (liver) glucose production and can hasten the fall in blood glucose levels leading to an early onset of fatigue.
Alcohol also depletes the body of it’s glycogen stores. Glycogen is the stored and readily available form of glucose, found in the liver and muscles. Adequate glycogen stores, in addition to food consumed, are needed to maintain your blood glucose levels during intense activity. Replenishing glycogen stores after each match is an essential part of recovery and will influence your future athletic performance.
Protein synthesis is briefly increased after exercise. This allows muscle tissue to repair. Enhanced protein synthesis is also the mechanism by which muscle mass and strength increases with training. Alcohol has been shown to dampen this important response to exercise. A recent study showed that alcohol consumption reduced peak muscle strength (Barnes, 2010).
Alcohol may prevent muscle recovery by other mechanisms as well. Alcohol consumed in large quantities can disrupt normal sleep patterns. This in turn, can decrease the secretion of human growth hormone (HGH) by as much as 70% (Girth and Manzo, 2004). HGH is a potent anabolic hormone that is needed to maintain and/or put on muscle mass.
It is a well known fact that alcohol is a diuretic, meaning that alcohol increases urinary output. Alcohol consumption can cause a decrease in total body water and cause dehydration. The equivalent of four mixed drinks (with 50g of alcohol in 250mL of water) causes a loss of 600 to 1000mL of water in several hours (Swift, 1998). Understanding that a loss of as little as 1 to 2% total body water can lead to a decrease in peak performance, the diuretic effects of alcohol alone could have a negative effect on your game.
Technically, alcohol is a nutrient because is provides energy (calories). Alcohol has 7 calories per gram making it almost as “fattening” as fat, which contains 9 calories per gram. Although high in calories, alcohol has no nutritional value. Even worse, alcohol inhibits the absorption and functions of the B vitamins thiamin, Vitamin B12, and folic acid. These B vitamins are involved in various metabolic pathways including protein synthesis and oxygen capacity, and also play a role in red blood cell formation, all of which in the long term could reduce performance.
To conclude, alcohol could have a negative effect on your performance on the court. Alcohol disrupts carbohydrate and protein metabolism, is a diuretic, and can lead to vitamin deficiencies. Now, for the good news, moderate drinking may have a protective effect on cardiovascular health by lowering the risk of coronary heart disease. Moderate drinking is considered to be no more than two drinks per day for men and one per day for women (unless a history of breast cancer). For the competitive squash player, I would recommend the guidelines set by the American College of Sports Medicine: 1. Pre-event: Avoid alcohol intake beyond “social drinking”, which I would define as two drinks for men and one for women for 48 hours. 2. Post-exercise: Rehydrate and consume food prior to consuming alcohol.
As with so many things in life, the key is moderation!