When's the Best Period to Work Out

Afternoon Advantages

Plenty of people tout the benefits of early morning sweat sessions, but if you can't fit in a workout before noon, don't sweat it. Research suggests the body could adapt to regular gym dates, so if we hit the weight room every day at 4 p.m., eventually we might perform better at that time than at any other time of day.  These findings are similar to earlier research, which suggests that sticking to a specific workout time can result in better performance, higher oxygen consumption, and lower perceived exhaustion.  But scheduling a workout is more complicated than choosing a number on the clock.

Your body’s core temperature is an important factor in determining the quality of exercise. A cold body leaves muscles stiff, inefficient, and susceptible to sprains, whereas higher body temperatures leave muscles more flexible. Body temperature typically increases throughout the day, so muscle strength and endurance may peak in the late afternoon, when body temperature is highest.  The afternoon is also when reaction time is quickest and heart rate and blood pressure are lowest, all of which combine to improve performance and reduce the overall likelihood of injury.

Morning Perks

It's sometimes easier to keep amorning workout routine consistent. Afternoon and evening workouts are more likely to conflict with other responsibilities as the day progresses. Plus a full day’s work can take a serious toll on willpower—which can overcome any gym-goer’s best intentions.

Morning workouts might also be a good option for stress-free snoozing. Since exercise increases heart rate and body temperature, working out too late in the evening (generally after 8 p.m.) maydisrupt sleep, while one study showed that working out at 7 a.m. (compared to 1 p.m. or 7 p.m.) may help people sleep more soundly at night. 

Finally, one study found that 45 minutes of moderate morning exercise (like walking briskly on the treadmill) helped curb appetite directly after working out.  Research also shows that people can burn up to 20 percent more body fat exercising on an empty stomach—much easier to do first thing in the a.m. than at night.