Enjoying a cold beer after a tough trail or a time trial is common practice amongst runners, but what is the impact on the running performance?
Alcohol and metabolism
Alcohol metabolism occurs primarily in the liver and it can be oxidized at a rate of 100mg/kg/hour (that is 0.5-1 unit per hour). Alcohol is metabolized at a specific rate for every individual and cannot be increased or decreased (by for example exercise). Alcohol is seen as a toxin to the body and gets preference to be metabolized and excreted, therefore alcohol interferes with the liver’s capability to produce glycogen and can result in suboptimal glycogen recovery or even hypoglycemia (low blood sugar).
Alcohol interferes with nutritional goals
Alcohol is an energy-dense nutrient that contains 27kJ or 7kcal per gram. Frequent episodes of heavy intake can be expected to increase total energy intake and usually, alcoholic binges goes hand in hand with the consumption of high fat foods. Due to alcohol being energy-dense it should be limited where you would like to lose weight.
Alcohol intake post exercise can interfere with your recovery goals. It is important to first consume carbohydrate and protein to assist in glycogen recovery and repair damaged muscles. If you do achieve your nutritional goals post event, adding some alcohol may not impair the recovery of muscle glycogen stores.
Common medical practice for soft tissue injuries is with RICE (rest, ice, compression and elevation). Alcohol is a potent vasodilator and might cause or increase undesirable swelling around damaged sites and impede the repair process.
Alcohol interferes with rehydration
Alcohol is a diuretic. Ingestion of 1g alcohol increases urine output by 10ml.
When rehydrating, this should be done with appropriate sports drink, oral rehydration solution etc. Low-alcohol beers may be suitable to encourage fluid intake, however drinks that contain more than 2% alcohol are not recommended for rehydration.
Alcohol’s effect on running performance
Heavy alcohol intake the night before a race or exercise session will interfere with performance. Studies have proven that after a high alcohol ingestion the night before, athletes felt less fresh, more tired, more nauseous, less alert and generally less well.
The intake of alcohol immediately before or during running does not enhance performance and may in fact impair performance. With trail running it carries the added risk because judgement and psychomotor performance are most affected.
Alcohol is not an essential part of the diet but can be enjoyed in moderation without affecting your running performance or health if used sensibly.