Popular Pre-Workout Supplements Linked to Dangerous Sleep Loss

Wired: Pre-workout supplements are one of the fastest-growing categories in fitness, and most are loaded with caffeine. If you’ve ever taken a pre-workout and found yourself staring at the ceiling at midnight, this won’t shock you. But a new study is raising red flags about what pre-workouts are doing to young people’s sleep — and their health.

The Study: Researchers surveyed over 900 Canadian adolescents and young adults about their supplement habits and sleep patterns, and found that pre-workout users were more than twice as likely to sleep five hours or less per night. Many pre-workouts contain 90 to over 350 mg of caffeine. Caffeine blocks adenosine, the chemical that builds up throughout the day and makes you sleepy, and can delay the onset of melatonin. That combination, researchers say, is a problem for a demographic that should be getting seven to 10 hours of sleep a night.

The Takeaway: Researchers recommend avoiding pre-workout 12 to 14 hours before bed. Or using a stimulant-free alternative, like products with citrulline, beta-alanine, and creatine.

Keep in Mind: This was a cross-sectional study capturing a snapshot in time. It can’t prove the supplements directly caused the sleep loss as other factors could play a role.