Can strength training cause insomnia?

The answer is not necessarily. It may help you sleep deeper and more soundly, or it may make you toss and turn until the middle of the night. It all depends on how you arrange your training.

A novice student I just taught a while ago is a typical counter-example. The young man had just graduated and had a tight time schedule. He could only squeeze in time to go to the gym at 9:30 every night. He rushed to the personal limit of squats and deadlifts. Every time he practiced until about 11 o'clock, he was sweating and his heart was still pounding. When he went home and took a shower, he lay in bed and his heart was still pounding. His mind was filled with the refreshing feeling of just lifting 180 pounds. He stayed up until two o'clock with his eyes open and could not sleep. He came over to ask me if there was something wrong with my strength training. In fact, it is not the fault of the training itself. High-intensity resistance training will increase adrenaline and cortisol levels in a short period of time, and at the same time increase core body temperature. If the training is completed less than 3 hours before bedtime, the sympathetic nerves will always be in a state of high excitement, and falling asleep will naturally become difficult. Previous studies in the field of sleep have mentioned that extreme strength training within 2 hours before going to bed will lengthen the sleep latency by about 20% on average, which means it takes nearly one-fifth more time to fall asleep than usual.

On the other hand, not all strength training is linked to insomnia. There are a lot of fitness enthusiasts around me who work from 9 to 5. They go to the gym every Monday, Wednesday, and Friday after get off work at 6 p.m., and do chest, back, and leg rotations for an hour. After the workout, they eat a fat-reducing meal and walk for two rounds. Then they go home and lie on the bed with pillows on them. The problems that they always had before, such as difficulty falling asleep and waking up easily, have improved a lot. In the past two years, I had to stay up late and night to work on projects, and my insomnia was so severe that I couldn't sleep half the night. Later, I forced myself to do strength training for an hour every Wednesday and Friday at 4 pm. I persisted for less than half a month, and the time it took me to fall asleep was reduced from the previous forty minutes to about ten minutes, and the duration of deep sleep in the sleep monitoring increased by almost half an hour. The current academic consensus is quite clear. Regular medium- and low-intensity strength training can regulate autonomic nervous function and reduce resting heart rate. After moderate muscle fatigue, it can reduce distracting thoughts before going to bed, which is positive for improving sleep quality.

Of course, some people say, "I can sleep soundly even if I train at ten o'clock every night." This is actually a matter of individual differences. Many veterans who have practiced for five or six years have already adapted their bodies to the rhythm of night training. After training, the fluctuation range of cortisol is very small. In addition, after training, they will stretch and relax for more than ten minutes, and their nerves can be calmed down quickly, which will naturally not affect their sleep. However, novices should not try this rashly. There are also people who always drink large doses of nitrogen pumps and super strong coffee when training. Let alone training, drinking two cups of strong coffee on an empty stomach at night will prevent them from falling asleep without training. This cannot be left to strength training.

If you really only have time to train at night, don’t panic. Move all the max-strength groups to the weekend during the day, and do regular hypertrophy groups when training at night. Control the weight so that you can do 12-15 times to failure. After training, don’t hold your phone and scroll through fitness-related content. The more you read, the more excited you will be. Take a cooler bath, do mindful breathing for a few minutes, and wait for your body temperature to drop before lying down. You will basically not have the trouble of insomnia.