Alcohol and the athlete continue to be linked together both anecdotally within the media and quantitatively in the literature. The detrimental effect of alcohol on human physiology has been well documented with acute alcohol ingestion affecting many aspects of metabolism, neural function, decreased testosterone, cardiovascular physiology, thermoregulation, hydration and skeletal muscle weakness.
Alcohol intake has been demonstrated to impair metabolic pathways that result in the generation of glucose (energy) and reduce muscle glycogen (energy) stores. Glucose (energy) availability plays a pivotal role in endurance performance and further readily available stores of energy are necessary to fuel protein synthesis during muscle recovery from exercise.
Alcohol acts as a depressant and thus acts to reduce central nervous system (CNS) excitability and cerebral activity. Impaired CNS function results in decrements in cognitive function and motor skills. A CNS that is weakened can result in decreased performance on skilled tasks that require reaction time, fine motor control, levels of arousal, and judgment.
Post exercise alcohol intoxication interferes with the free testosterone and serum testosterone. Testosterone is heavily involved in muscle adaptation induced by training programs that utilize resistance training. The level of alcohol intoxication seems to play an important part in how testosterone levels are affected. It is shown that the greater amount of alcohol consumed the greater amount of damage that is inflicted on testosterone levels.
Aerobic performance has also been shown to decrease as a result of consuming alcohol post-exercise. The chemical processes which take place during aerobic metabolism are negatively altered following alcohol consumption. Altered chemical processes related to alcohol ingestion can cause an increase in lactate production, which, can be a factor in poor aerobic performance. Alcohol also increases the risk of dehydration, and dehydration is associated with a reduction in aerobic performance. Research also shows that there are significant decreases in average peak isometric, concentric and eccentric force when alcohol is consumed post-exercise.
It is widely recognized that alcohol negatively affects hydration levels, as it act as a diuretic. Dehydration is further enhanced via alcohols influence on peripheral vasodilation (enlargement/expansion of veins and arteries). This primarily increases fluid loss through evaporation, and elicits a marked fall in core temperature. These affects clearly display the potential for an adverse effect on performance.
Skeletal muscle is likely to undergo several detrimental actions in response to alcohol consumption. Chemical process taking place within the muscles are disrupted resulting in impairment of excitation and contraction process occurring in the muscle (decreasing strength output). Increased blood flow to exercised areas of the body is common following intense training. Post-training ice baths and compression wraps are often recommended to help reduce blood flow to the stressed area. The vasodilation effects following alcohol consumption can cause an increase of blood flow to the damaged areas, prolonging recovery.
TRAIN HARD – EAT RIGHT – RECOVERY PROPERLY
Dan Hammes, MA, CSCS, CSCCa, is a former Assistant Strength and Conditioning Coach of Olympic Sports at the University of Iowa, Iowa City, Iowa. For more information on the Iowa Strength and Conditioning Program, go to http://strength.sports.uiowa.edu/