Why can’t I fall asleep after exercising?

Being unable to sleep after exercising is mostly not a problem with the fitness itself. It is mostly due to the fact that the timing and intensity of exercise do not match your physical condition, triggering short-term abnormal fluctuations in nerves and hormones. I got off work late last Wednesday to catch up on a project, so I went to the gym at 7:30 to do leg workouts. I even beat my personal best in deadlifts and squats. My legs were shaking when I left the gym at 9:30. I thought I could have a good sleep when I went back so tired, but I ended up lying there until after 1:00 and still very energetic. The muscles in my legs would jump twice from time to time, and I didn't feel sleepy until I checked my phone until my eyes were sore. Later, after asking a familiar sports rehabilitation practitioner, I learned that high-intensity resistance or HIIT exercises will cause the body to secrete a large amount of adrenaline and cortisol in a short period of time. Cortisol, which is supposed to gradually decrease at night, is abruptly pulled back to the daytime level, just like a fan that is about to stop spinning is suddenly turned on to the highest gear. The sympathetic nerves are always in a state of high excitement. How can it be possible to sleep? Also, after exercise, the core body temperature will rise by about 1°C, and it is necessary for the core body temperature to drop to fall asleep. If you go to a sauna and take a hot bath after exercise, your body temperature will not go down for a long time, and it is normal to toss and turn.

However, not everyone suffers from insomnia when they exercise at night. I work with Lao Zhou at the same gym, who runs a late-night snack bar. He closes his stall at 10:30 every day. He always practices for an hour before going home. He snores when he touches a pillow. When I asked him, he said he was used to it. If he didn't practice on any day, he would feel uncomfortable and unable to sleep. This means that the body has established a new rhythm, and the regulation rhythm of hormones has been adjusted according to the training time, so there will be no excitement problem. Academic studies have indeed shown that people who maintain a fixed night training habit for a long time have better sleep quality than those who do not exercise. The so-called "exercise at night will definitely lead to insomnia" is not absolute.

Some people can't sleep because they don't pay attention to the details. They put in two pumps of nitrogen pumps before training to increase weight, or go out for a late-night snack with friends after training and drink iced Coke energy drinks. The metabolism cycle of caffeine takes four or five hours at least. If you drink this at 8 o'clock, it will still take effect at 12 o'clock, so you can count sheep with your eyes open. Some of them hold their cell phones and review with their muscle friends after practice whether the day's movements were standard or how much the weight has increased. The more they talk, the more excited they become. The nerves that should have been calmed are stirred up again, and of course they can't sleep.

In fact, it is easy to avoid this situation. If you are the type who is sensitive to nerves and can't fall asleep even if there is any movement, try to move high-intensity training no more than 3 hours before going to bed. Don't touch anything containing caffeine after training. Take a warm bath that is slightly lower than the body temperature. Sit there and stare for a while. Don't watch too exciting short videos. Basically, you will not stare and wait for dawn. If you really only have time to exercise at night, it doesn’t matter. Slowly lower the initial intensity and give your body a week or two to adapt. Once it understands your exercise pattern, it will actually help you sleep more soundly.