When Is the Best Time to Exercise?
The Science Behind Your Circadian Rhythm

Whether you’re an early bird or a night owl, optimizing your workout schedule can unlock better performance and deeper sleep. But does biology have a preference?

The debate between morning and evening workouts has persisted for decades. While consistency is undoubtedly key, emerging research suggests that your body's internal clock—or circadian rhythm—plays a pivotal role in how your muscles perform and recover.

The Case for Morning Movement

Proponents of morning exercise often cite metabolic benefits. A study published in the Journal of Physiology found that exercising in a fasted state (before breakfast) can improve insulin sensitivity and increase fat oxidation.

Furthermore, morning light exposure is a powerful "zeitgeber" (time giver) that helps regulate your sleep-wake cycle. A brisk run at 7 AM signals to your brain that the day has begun, leading to higher alertness levels throughout the morning.

However, there is a catch: body temperature is at its lowest in the morning. This means your muscles are colder and stiffer, potentially increasing the risk of injury if you don't warm up properly.

Why Evening Might Be Stronger

If you're looking to break personal records, the afternoon might be your golden hour. Between 2 PM and 6 PM, your body temperature peaks, optimizing muscle function and enzyme activity. Reaction times are quicker, and perceived exertion is lower.

"Performance metrics for strength and power output are consistently higher in the late afternoon," says Dr. Emily Chen, a sports physiologist. "Your body is simply primed for intensity."