Lukus Klawitter M.S
I am sure as close friends and family see the title of this post, they immediately assumed I wrote about the benefits of alcohol (specifically beer), and how it could increase variables like endurance performance and recovery. And yes, I strongly agree beer and endurance sports is like peanut butter and jelly, they are meant to be together. Unfortunately, in most scenarios this is not the case. Before I dive into the physiological effects of alcohol and endurance performance, I want to apologize to all of those who like me, appreciate the post training beer (n+1) or social happy hour with close friends. So, before you put PBR’s in your bike cages while spinning the trainer, read this brief overview on how alcohol affects various systems within the body.
Central Nervous System
Firstly, the acute effects of alcohol ingestion are fairly well known. Acute alcohol ingestion delays cognitive functioning and reduces our central nervous system performance, delaying reaction time, alertness, and awareness of body in space. Hindered central nervous system functioning increases the chance for injury and overall recovery.
Alcohol has no nutritional value and contains roughly 7kcals per gram. When alcohol has been consumed within a day of exercise, the body will metabolize the energy from alcohol over fats and carbohydrates which limits energy function and fat oxidation. Alcohol leads to suppressed function of the citric acid cycle, which slows fat oxidation and leads to more storage of body fat. Lastly, binge use of alcohol affects the uptake of glucose, lactate, and glycerol in the blood, preventing gluconeogenesis, which limits multiple energy pathways used during exercise. Lastly, at rest muscle glycogen metabolism is increased where we should be relying on slow aerobic metabolism of fats. Alcohol also can inhibit the small intestine’s ability to absorb key nutrients that are very important in energy metabolism like vitamin b12 and D.
Regular alcohol intake increases heart rate at rest and during exercise. However, no change in stroke volume is present thus, the heart is working harder with no increase in blood distribution throughout the body. Increased resting heart rate also delays recovery post exercise.
Skeletal Muscle and Hormones
Alcohol affects our ability to channel Ca+ within the muscle cell, which could decrease force output due to reduced function of the muscle contraction. The consumption of alcohol also leads to an inflammatory response and there is some evidence that shows alcohol may increase level of creatine kinase in the blood, which is a marker of overtraining and stress within the body. The inflammatory response also decreases anti-inflammatory markers and increases inflammatory markers, suggesting that alcohol should not be consumed when and injury has taken place. More on recovery, alcohol increases the stress hormone cortisol and decreases testosterone synthesis in the muscle another factor suggesting our post training beers are only delaying our ability to recover.
Within my last training build I really started to pay more attention to my resting heart rate values. Like many endurance athletes my resting heart rate is very low ~ 39-41bpm, however, the day after enjoying a few beers I would notice a rather large increase in my resting heart rate ~47-50bpm. Heart rate is a very simple measure but is evident in tracking sickness, overtraining, and fatigue. Those that are within race season that have high hopes on performance should limit alcohol consumption and have multiple per week when alcohol is not consumed. Additionally, there should be a fairly long time where no alcohol is consumed leading up to a big event. Therefore, for all of you connoisseurs out there, or those that enjoy meeting with friends over a beer, or celebrating for some event, take some of these variables into consideration. Try to end your consumption close to bedtime and stay hydrated. Or better yet, substitute your traditional beer with a GRUVI! Use code “MattH10” for 10% off your order!