Arnold Schwarzenegger Reveals Why Working Out Before Bed Can Be a Bad Idea

Arnold Schwarzenegger is sharing a clear warning for people who like to work out late at night.

The bodybuilding legend and movie star says intense exercise too close to bedtime can hurt sleep and slow down recovery. He explained this in his newsletter, Arnold’s Pump Club, where he often talks about health, fitness, and daily habits.

Schwarzenegger, who is now 78, said the advice is especially important today because many gyms are open 24 hours a day. With busy work and family schedules, a lot of people train late in the evening. Still, he believes that timing matters if you want real results.

According to Schwarzenegger, hard workouts done within four hours of going to bed can make it harder to fall asleep and stay asleep. He pointed to scientific research to back this up. “Scientists found that intense workouts four hours before bed can delay sleep, shorten it, and stress the nervous system,” he wrote. He added that lighter or moderate exercise in the evening is usually fine.

The study he mentioned came from Monash University and was published in the journal Nature Communications. Researchers looked at data from more than 14,000 active adults. They studied how workout time and intensity affected sleep length, resting heart rate, and heart rate variability, which is a key sign of recovery.

The results showed that very hard workouts late at night kept the body too alert when it should be calming down.

The study found that people who finished very intense exercise close to bedtime often fell asleep much later. In some cases, sleep was delayed by more than an hour. Sleep time was also shorter, and recovery markers dropped. Schwarzenegger summed it up simply: “That’s 80 minutes later falling asleep, 43 minutes less sleep, and a big drop in recovery.”

He also shared some good news. If intense training ended at least four hours before bedtime, it did not cause these problems. Inside that four-hour window, though, lighter workouts worked much better for sleep and recovery. “Within those four hours, shorter or easier workouts were much better for your body,” he explained.

Schwarzenegger understands that not everyone can train earlier in the day. Work and life do not always allow it. He said people should not panic if evenings are their only option. “If night is the only time you can train, don’t stress. Just be smart about it,” he wrote. His advice is to save the hardest sessions for earlier in the day when possible and keep evening workouts easier.

He also reminded readers how important sleep really is. Schwarzenegger often repeats one rule from his bodybuilding days: “You grow when you sleep, not when you train.” During sleep, the body releases growth hormone, which helps repair muscles and restore energy. Poor sleep can slow recovery, weaken the immune system, and affect strength gains.

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