Pumping iron or hitting the treadmill raises dopamine levels, those feel-good neurotransmitters. That’s usually a good thing—unless you plan on getting some shuteye in the next hour or two. Besides being linked with pleasure, dopamine is also connected with sleep saboteurs such as movement and attention. “Exercise close to bedtime can make it harder to sleep, because it can make you overly alert,” confirms Sack. If you can’t fit your workout in earlier, try calming exercises like yoga or tai chi.
- Recover Like a ProCheck out these 12 game-changing workout recovery tools.
- Best Health and Fitness Breakthroughs of 2014The year's best health and fitness research.
- 11 Foods Fitness Experts Never EatEven during the holidays.
- The 14 Most Popular Workouts of 2014We highlight the routines that helped you reach your fitness goals this year.