Is There a Best Time of Day to Strength-Train?

A new study suggests that weight-lifting in the morning may lead to a better workout afterward.

Photograph via Shutterstock.

You might already know that men’s testosterone levels taper off throughout the day as their bodies gradually consume the hormone. And no mid-afternoon caffeine fix will bring back the energy associated with the higher testosterone levels that are produced while we catch some Zs. But new research suggests there may be a natural way to keep those levels up throughout the day and ultimately lead to a highly efficient afternoon workout. 

Recently, scientists in the UK conducted a study with 18 rugby players and found that those who bench-pressed or squatted a few sets in the early morning outperformed their peers who hit the snooze button rather than the gym. The morning lifters also proved to have higher levels of testosterone as the day wore on. Those who were assigned to a morning sprint session also produced good performance results during their afternoon workout, but not as significant as those who strength-trained. 

The findings suggest that those who begin their day with some quality gym time have a slight advantage in their afternoon workouts, whether it’s a kickball game or a track workout.

But the study was small and left us with some lingering questions. To better understand the impact testosterone levels have on everyday gym-goers’ fitness performances, we spoke with George Washington University School of Public Health and Health Services’ Dr. Todd Miller, an associate professor of exercise science.

“In theory, if we train in the morning and it results in an elevated testosterone level, then testosterone should be higher at any given time throughout the day,” Miller explains. “However, studies have shown that weight training in the morning is no different from weight training in the afternoon when it comes to muscle strength and size, with both times being equally effective at causing increases.” 

The more testosterone, he adds, the better, especially for men who have goals to bulk up. “Testosterone is a very anabolic hormone, meaning one of its primary physiological roles is to build muscle through increased protein synthesis. It also speeds recovery between training sessions, allowing one to do more physical work per unit of time,” Miller says. “It is very clear that there is a direct relationship between testosterone levels and muscle mass, energy, and recovery, so most men will benefit from high levels.”

Back to those rugby players, though. Do we really miss a critical window of opportunity to gain muscle mass if we hit the snooze?

“The time of day in which one gets the most effective workout is highly variable and highly personal. Some people love training in the morning, while others hate it,” Miller says. “It’s really all about personal preference.”

Miller’s final suggestion to keep those testosterone levels in check? Get some sleep.

“This is one of the reasons getting a good night’s sleep is important: so that testosterone production remains high.”

The full study was published in the Journal of Science Medicine in Sport