We Drink More Alcohol on Gym Days

A new Northwestern Medicine® study finds that on days when people exercise more - typically Thursdays to Sundays - they drink more alcohol, too.

This is the only study to use smartphone technology and a daily diary approach for self-reporting physical activity and alcohol use.

"Monday through Wednesday people batten down the hatches and they cut back on alcohol consumption," said David E. Conroy, lead author of the study. "But once that ‘social weekend' kicks off on Thursdays, physical activity increases and so does alcohol consumption."

Conroy is a professor of preventive medicine and deputy director of the Center for Behavior and Health at Northwestern University Feinberg School of Medicine. He also is a faculty affiliate of the Methodology Center at The Pennsylvania State University, where the research was conducted.

The study was published online in Health Psychology, an American Psychological Association journal.

"Insufficient physical activity and alcohol use are both linked to many health problems, and excessive alcohol use has many indirect costs as well," Conroy said. "We need to figure out how to use physical activity effectively and safely without having the adverse effects of drinking more alcohol."

What impact does alcohol have on your fitness regime? Unfortunately, toasting your gym session with post-exercise drinks at home or down the pub can undo all the good work you've just put in. There's 180 calories in the average pint of lager and 159 calories in a 175ML glass of 13% ABV white wine, so you could end up topping up the weight you thought you'd lost through your fitness regime in no time at all. For instance, if you've just run for half an hour it will only take two pints to put back on the calories you've just burned off through exercise.

The way alcohol is absorbed by the body can also reduce the amount of fat you're able to burn by exercising. Because your body isn't designed to store alcohol, it tries to expel it as quickly as possible. This gets in the way of other processes, including absorbing nutrients and burning fat. So as well as slowing down the burning of calories, alcohol gets in the way of the nutritional benefits of the healthy meals you eat.
Running on empty

Fitness experts agree that to get the most from cardiovascular exercise such as running or swimming, you have to put in the physical effort. But while your hangover may make a less hectic workout feel welcome, it's harder to build up the head of steam you need to stay in shape when you have a headache, and nausea is beginning to kick in. The night before's alcohol leaves your body dehydrated, even before your session starts.

One hundred and fifty study participants, ages 18 to 89, recorded their physical activity and alcohol use in smartphones at the end of the day. They did so for 21 days at a time, at three different times throughout one year.