Both of these result in impaired athletic performance. A secondary effect of an inadequate glycogen supply is that muscle tissue may lack the energy supply necessary for cell repair following strenuous exercise. Alcohol's impact on the cardio-vascular system can be significant. Alcohol ingestion tends to raise blood pressure. A rise in blood pressure can result in the heart having to pump harder in order to move the blood in the body.
Alcohol use can cause abnormal heart rhythms in athletes.
In some people even as little as 3 ounces of alcohol can cause a form of abnormal heart beat called ventricular tachycardia. Alcohol also increases the synthesis of cholesterol, which increases the risks of coronary heart disease. Chronic alcohol abuse causes progressive weakening of the muscles, both cardiac and skeletal muscles. Sleep patterns are affected by even moderate alcohol intake. As little as one ounce of alcohol consumed before going to bed can suppress deep sleep, cause fragmented sleep and thus interfere with truly restful and restorative sleep.