Alcohol - What Causes Fatigue: Chronic Fatigue

Content provided by the Faculty of the Harvard Medical School

Alcohol

Alcohol can cause fatigue in two ways. First, as a sedative, it depresses the central nervous system. So drinking wine, beer, or hard liquor during the day can make you feel drowsy or lethargic. If you didn't sleep well the night before, even just one drink can make you drowsy, especially if you drink during one of your usual low-energy times, for example, mid-afternoon or late evening.

Second, many people mistakenly think that having a nightcap will help them sleep soundly. Although a drink may help some people fall asleep more quickly because of its sedative effects, alcohol has other effects that can interfere with sleep. Several hours after drinking, alcohol raises the body's level of epinephrine, a stress hormone that increases the heart rate and generally stimulates the body, which can result in nighttime awakenings. Indeed, alcohol may account for 10% of chronic insomnia cases. Alcohol can also interrupt sleep by relaxing throat muscles, thereby worsening nocturnal breathing problems and causing sleep apnea. It also may disrupt sleep by causing the need to urinate during the night.

Last updated:	January 23, 2007