What Are the Best Times of Day to Exercise?
Table of Contents:
Do you prefer working out in the morning or exercising at night? Many fitness enthusiasts fall into two extremes—either they head out at dawn for a workout or go for a night run just before bed. However, a recent study suggests that many people are choosing the wrong time to exercise!
Early Morning Is Not the Optimal Time to Exercise
Many older adults wake up around 5 or 6 a.m. and head out for a walk or morning workout. But is exercising at dawn really beneficial for health? A 2023 study published in Nature Communications found that working out too early in the morning is associated with a higher risk of all-cause and cardiovascular mortality.
Compared to exercising in the morning (05:00–11:00), engaging in physical activity between late morning and afternoon (11:00–17:00) was associated with an 11% lower risk of all-cause mortality and a 28% lower risk of death from cardiovascular diseases.
Why is early-morning exercise not recommended? Between 6 a.m. and 8 a.m., blood pressure naturally peaks, and exercise during this window can further increase cardiac load and blood pressure—posing potential risks, especially for individuals with hypertension or cardiovascular conditions.
Late-Night Workouts Are Also Suboptimal
In addition to avoiding workouts at dawn, exercising right before bed is even less advisable. A study published in Nature Communications in April 2025 tracked nearly 15,000 fitness enthusiasts over the course of a year and analyzed their sleep patterns. The findings revealed that exercising close to bedtime led to various sleep disturbances: delayed sleep onset, reduced total sleep time, lower sleep quality, and disrupted nighttime resting heart rate.
The study showed that performing high-intensity exercise within 4 hours before bedtime—especially within 2 hours—can delay sleep onset by 80 minutes, shorten sleep duration by 42.6 minutes, reduce sleep quality by 5.6%, and lead to heart rate irregularities (elevated resting heart rate and decreased heart rate variability at night).
Therefore, it is not advisable to engage in vigorous exercise close to bedtime. Ideally, workouts should conclude at least 4 hours before sleep. For example, if you go to bed at 10 or 11 p.m., you should finish your workout by 6 or 7 p.m. at the latest, and avoid high-intensity exercise thereafter.
Evening workouts, especially intense ones, can stimulate the body and raise "yang" energy, potentially leading to heightened excitement and insomnia.
Ideal Times of Day for Exercise
8:00–10:00 a.m.
A large-scale study published in European Journal of Preventive Cardiology in 2022 involving over 86,000 participants found that exercising in the early morning (around 8 to 10 a.m.) was associated with the lowest risk of coronary heart disease and stroke—reducing the risk of coronary heart disease by 16% and stroke by 17%.
Additionally, a 2020 study in the International Journal of Cancer showed that compared to those who did not exercise, individuals who worked out between 8 and 10 a.m. had a 26% to 27% lower risk of developing breast and prostate cancers. Clearly, 8–10 a.m. is a prime time for exercise!
4:00–6:00 p.m.
For working individuals, daytime may be unavailable for exercise, and nighttime workouts could interfere with sleep. In such cases, late afternoon (4–5 p.m.) is considered a "golden hour" for physical activity. By this time, the muscles and ligaments are fully warmed up from the day's activities, and heart rate and blood pressure are relatively stable—making it ideal for moderate to vigorous aerobic exercises such as running, playing sports, swimming, or gym workouts.
Since 4–5 p.m. typically overlaps with working hours, a practical suggestion for office workers is to exercise between 5:30 and 6:30 p.m. This time window is just before sunset when yang energy is still active, thus avoiding conflicts with work, dinner, and the natural decline in physiological energy in the evening.
Three Key Points to Remember for Daily Exercise
How long should each session last? — 30 to 60 minutes
Some people exercise for two hours or even longer. However, longer sessions are not necessarily better. A 2018 study published in The Lancet Psychiatry analyzing data from over 1.2 million people found that the optimal workout duration is 30 to 60 minutes per session, with peak benefits around 45 minutes. Sessions exceeding 90 minutes may even lead to negative effects.
What type of exercise is best? — Combine Aerobic and Strength Training
For optimal results, it's important to incorporate both aerobic exercises and strength training. While aerobic activities like running, walking, cycling, and swimming mainly improve cardiovascular health, they do little for muscle strength.
Strength training is essential for maintaining and preserving muscle mass. Studies have shown that performing strength exercises twice a week after the age of 40 significantly lowers all-cause mortality and reduces the risk of cardiovascular disease and cancer-related deaths. Recommended strength training options for individuals over 40 include: bodyweight exercises (such as squats and push-ups), resistance band workouts, and gym-based strength training.
What intensity is appropriate? — Moderate intensity
Exercise that’s too mild won’t yield much benefit, while overly intense workouts can raise the risk of injury. Both current research and expert recommendations suggest that moderate-intensity exercise is the most beneficial.
How can you gauge moderate intensity? One method is to monitor heart rate: aim for 60% to 85% of your maximum heart rate, which typically translates to 100–140 beats per minute during activity.
A simple rule of thumb: if you're slightly out of breath during exercise but can still hold a conversation (though not sing), you're likely working at moderate intensity. If you're too breathless to speak more than a few words, the intensity may be too high.
