Do you head to the bar to celebrate when your softball team wins? Do you shuffle off to the gym the morning after a night out with friends? Numerous studies have shown that people who exercise regularly also tend to drink alcohol in moderation. Now two new studies suggest that this is not just a coincidence. Alcohol and exercise may actually be interrelated: Both activities release chemicals into our brains that make us feel good, and each activity also motivates us to engage in the other.
J. Leigh Leasure, an associate professor at the University of Houston and director of the school’s behavioral neuroscience lab, wondered with her colleagues, why do these contradictory activities go hand in hand? They conducted an extensive review of previous studies, publishing their findings in the November 2015 issue of Frontiers in Psychiatry.
The correlation between exercise and moderate alcohol consumption has been evident for decades. People who exercise tend to engage in other healthy behaviors, like eating nutritiously and avoiding cigarette smoke. Typically, regular alcohol consumption is not regarded as one of these healthful behaviors, yet this correlating relationship with exercise has been observed and identified time and again.
One study found that moderate drinkers were twice as likely to be physically active, and another found that regular consumers of alcohol are 10 percent more likely to exercise vigorously than abstainers. But the majority of these studies relied on subjects' memories—participants reported how often they drank and exercised over a long period, such as several months or a year. The studies also rarely recorded direct links between exercise and drinking—say, whether someone hit the gym on the same day as they hit the bar.
A study from Penn State, published in the June 2015 issue of Health Psychology, attempted to address this problem by having participants keep a daily log of alcohol consumption and physical activity for three weeks. Researchers gave participants apps for their smart phones, which made recording nearly instant.
A group of 150 adults, aged 19 to 89, evenly split between gender and with differing levels of education, ethnicity and employment status, answered an initial questionnaire about their lifestyles and health and then used the app for 21-day periods three times over the course of a year. During each three-week phase, they entered in the app at the end of the day how many servings of beer, wine or liquor they consumed and how many periods of mild, moderate or vigorous activity they engaged in for at least 10 minutes. The app immediately transmitted the reports to the research laboratory.
Analyzing the data, the scientists found further proof that moderate drinkers exercise more often than their non-drinking peers. But they also found that people who drank more on a certain day also tended to exercise more on that same day. The researchers saw an unequivocal link between, for example, an extra half-hour at the gym in the morning and an extra glass of Champagne at happy hour.
The University of Houston found another clue in studies involving rodents. Researchers have found that rodents, like humans, will autonomously choose and enjoy both exercise and alcohol. One study found that when presented with alternating access to alcohol and exercise, rodents engaged in both activities at comparable, stable levels. "It's a sort of hedonic substitution," said Leasure. "I don't have my exercise reward, but I can engage in this alcohol reward.'"
Leasure and her team posit that the effects of exercising and drinking alcohol on the brain offers one of the most compelling explanations for the relationship. "The reason that exercise is rewarding is that it causes the release of chemicals in the brain that make people feel good, like endorphins and dopamine," Leasure explained to Wine Spectator. "Alcohol also increases the levels of dopamine and endorphins, so there's an overlap in how they affect the brain, chemically speaking." People who are not dependent on either activity may engage moderately in each to prolong the rewarding feelings of happiness produced by these chemicals.
That may explain the neural connection between physical activity and exercise, but it doesn't account for personality traits and impulses that also shape human behavior. Leasure and her team suggested four joint motivations between drinking and exercise: work hard–play hard, celebration, body image and guilt. The first two propose that alcohol can be an indulgence following a challenging workout or a reward after a victorious race. In the latter two, exercise offsets drinking calories or compensates for irresponsible behaviors, such as drinking too much.
The researchers also considered personality and social factors. Extroverts are more likely to call for another round of beers for friends at a party or to get a team together for a pickup soccer game. Socially anxious individuals may avoid boisterous drinking events and may also eschew the gym, for fear of working out in public.
Lest regular exercisers worry about their drinking habits, the researchers stress that the intertwined relationship is not harmful in non-dependent individuals—if you don't drink heavily and you're not addicted to the gym, don't be concerned. "I think this is something that people need to be aware of, not because it's going to make them a problem drinker," said Leasure. "But they may just want to take note, 'Do I tend to have another drink on days when I exercise?' I think it's something to help them make healthy choices if they want to use the information that way."