Arnold Schwarzenegger has a clear message for anyone who saves their toughest training for the end of the day. With 24 hour gyms everywhere and busy schedules squeezing workouts into whatever slot is left, late evening sessions have become the norm for a lot of people. But the bodybuilding legend says timing can matter just as much as effort, especially when sleep is on the line. His point is simple, pushing too hard too close to bedtime may work against the results you are chasing.
Schwarzenegger shared the advice in his Arnold’s Pump Club newsletter, urging night owls to think strategically rather than automatically defaulting to high intensity sessions. He notes that intense workouts within about four hours of sleep can delay when you fall asleep, cut into total sleep time, and keep the nervous system revved up when the body should be shifting into recovery mode. In contrast, lighter or moderate movement in the evening is usually easier on the system. That difference matters because recovery is not a bonus, it is part of training.
To back it up, he pointed to research from Monash University published in Nature Communications that looked at data from 14,689 active adults. The study tracked how workout timing and training load related to sleep onset, sleep duration, resting heart rate, and heart rate variability. The pattern was consistent, when people went all out close to bedtime, the body stayed too activated at the exact time it should be winding down. In practical terms, the study linked maximum effort workouts to later bedtimes, including an average delay of about 36 minutes when the session ended two hours before a typical bedtime, and up to 80 minutes later when the session finished two hours after that usual point.
Schwarzenegger summed up the impact in a way that is hard to ignore, an 80 minute delay in falling asleep, roughly 43 minutes less sleep, and heart rate variability reduced by about 33 percent. He also highlighted an important detail, if the workout ended at least four hours before bed, even intense training did not show the same negative effects. And within that four hour window, shorter, lighter sessions seemed far kinder to sleep and recovery. For anyone who has no choice but to train at night, his workaround is to schedule the hardest sessions earlier when possible, keep evening training moderate, and lean into calming habits that help the body switch gears.
Do you prefer morning workouts, or are you firmly on team evening gym, and how do you make it work without sacrificing sleep? Share your routine in the comments.
