For most of us, the “best” time of day to work out is simple: When we can.
Maybe that’s before or after work. Or when the gym offers free daycare. Or when our favorite instructor teaches our favorite class.
That’s why we call it a “routine.” And if the results are the same, it’s hard to imagine changing it up.
But what if the results aren’t the same?
pojoslaw/Thinkstock
They may not be, according to a new study from a research team at Skidmore College in Saratoga Springs, N.Y.
Women who worked out in the morning lost more fat, while those who trained in the evening gained more upper-body strength and power. As for men, the performance improvements were similar no matter when they exercised. But those who did so in the evening had a significant drop in blood pressure, among other benefits.
The study is part of a growing body of research showing different results for different times of day among different populations. As it turns out, when you exercise can ultimately have a big effect, not just on strength and fat loss, but also heart health, mood, and quality of sleep.
An accidental discovery
The original goal of the Skidmore study was to test a unique fitness program with a group of healthy, fit, and extremely active adults in early middle age.
The program includes four workouts a week, each with a different focus: strength, steady-pace endurance, high-intensity intervals, and flexibility (traditional stretching combined with yoga and Pilates exercises).
But because the group was so large – 27 women and 20 men completed the 3-month program – they had to split them into morning and evening workout groups.
It wasn’t until researchers looked at the results that they saw the differences between morning and evening exercise, says lead author Paul Arciero, PhD.
Dr. Arciero stressed that participants in every group got leaner and stronger. But the women who worked out in the morning got much bigger reductions in body fat and body-fat percentage than the evening group. Meanwhile, women in the evening group got much bigger gains in upper-body strength, power, and muscular endurance than their morning counterparts.
Among the men, the evening group had significantly larger improvements in blood pressure, cholesterol levels, and the percentage of fat they burned for energy, along with a bigger drop in feelings of fatigue.
Strategic timing for powerful results
Some of these findings are consistent with previous research. For example, a study published in 2021 showed that the ability to exert high effort and express strength and power peaks in the late afternoon, about the same time that your core body temperature is at its highest point.
On the other hand, you’ll probably perform better in the morning when the activity requires a lot of skill and coordination or depends on strategic decision-making.
The findings apply to both men and women.
Performance aside, exercise timing might offer strong health benefits for men with type 2 diabetes, or at high risk for it.
A study showed that men who exercised between 3 p.m. and 6 p.m. saw dramatic improvements in blood sugar management and insulin sensitivity, compared to a group that worked out between 8 a.m. and 10 a.m.
They also lost more fat during the 12-week program, even though they were doing the exact same workouts.