Think of all the things that make you want to have a drink. Maybe it's a stressful day at the office, or watching a baseball game on a sunny afternoon. Few people probably put going to the gym on that list.
But a new study conducted by researchers at Northwestern University in Illinois found that we tend to consume more alcohol on days we've exercised.
Previous studies have found that physically active people drink more than sedentary people do, but this study, published online in the journal Health Psychology, found no such link. What it did find is that hitting the gym one day makes you much likelier to hit the bar that night.
"We zoomed in the microscope and got a very up-close and personal look at these behaviours on a day-to-day basis and see it's not people who exercise more drink more – it's that on days when people are more active they tend to drink more than on days they are less active," David Conroy, lead author of the study, said in a release.
In the study, 150 people between the ages of 18 and 89 recorded their physical activity and alcohol consumption every day for 21 days at a time. They did this at three different times throughout one year. All the information was recorded by study participants on smartphones.
"In this study, people only have to remember one day of activity or consumption at [a] time, so they are less vulnerable to memory problems or other biases that come into play when asked to report the past 30 days of behaviour," said Conroy, professor of preventive medicine at the Northwestern University's school of medicine. "We think this is a really good method for getting around some of those self-report measurement problems."
In the study, people typically exercised more from Thursday to Sunday than during the rest of the week, which is also when they were more likely to drink. You may think, of course people drink more on weekends than on Mondays.
But the link between exercise and alcohol consumption still held after researchers controlled for the fact that there are typically more opportunities to go out and drink on weekends.
Why do people drink more on days they've been physically active?
Conroy isn't sure.
"Perhaps people reward themselves for working out by having more to drink or maybe being physically active leads them to encountering more social situations where alcohol is consumed – we don't know," Conroy said.
The study also hypothesized that exercise drains people's willpower, making them more susceptible to alcohol's temptations.
"Once we understand the connection between the two variables, we can design novel interventions that promote physical activity while curbing alcohol use," Conroy said.