New research is adding important considerations to what we know about exercise and sleep. While it is long been established that regular physical activity improves sleep quality, intensity and timing now seem to play a more direct role than previously understood. Specifically, training too close to bedtime, particularly at higher intensities, can interfere with your ability to fall asleep and stay asleep. This is largely due to the body’s physiological response to exercise including elevated core temperature, increased heart rate, and a surge in stress hormones like cortisol and adrenaline all keep the nervous system in a heightened state of alertness.
The review in question recommends finishing high intensity workouts at least four hours before your intended bedtime. That recovery window gives your system time to return to a balance, rested state. Your heart rate begins to normalize, your body temperature cools, and your hormonal state starts to shift toward parasympathetic dominance, which supports restful sleep. If you are training hard at 9pm and trying to be asleep by 10:30pm, you are asking your body to make a transition that it may not be ready for.
I wish I could say this is part of the reason our schedule at AIM Athletic ends with a 6:30pm session, but if like to come to one of our later sessions, and you are aiming to be in bed around 10:30, you are allowing your body the recommended buffer. That means our members can still get in a full session, whether that is small group strength, personal training, or active rehab, without compromising sleep quality or the recovery process that depends on it. We have seen firsthand how even well intentioned training can backfire when recovery is not properly supported, and sleep is a cornerstone of that equation.
In active rehab especially, we often work with individuals whose nervous systems are already under strain, whether due to pain, injury, or stress. Late night exercise can further delay downregulation, which is critical for tissue healing and restoring movement quality. In these cases, a morning or late afternoon session tends to work better, but if evening is the only option, the research would suggest that you taper the intensity or focus more on mobility and controlled movement to avoid overstimulation.
Not everyone responds to training the same way, and there are always exceptions. Some people can train late and still sleep well. But if you are finding it hard to fall asleep or feel groggy in the morning after evening workouts, this may be the missing link. With the right timing, you can still train hard, make progress, and wake up feeling more rested and recovered.
You've got the info, now it's time to take AIM!
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