Medically reviewed by
Dacelin St Martin, MD
Triple board-certified in Sleep Medicine,
Internal Medicine, and Pediatrics.
Exercise in any form is beneficial for your sleep and overall health. However, more often than not, one may have to choose between strength training or cardio.
The Iowa State Study
A study conducted by scientists from Iowa State University, “Comparative Effects of Aerobic, Resistance, and combined Exercise on Sleep,” shows that regular strength training workout benefits people who have trouble sleeping and are physically inactive or overweight.
According to Angelique Brellenthin, the lead author of the study and assistant professor of kinesiology at Iowa State University, “this is the first large-scale study to explicitly assess the effects of various types of exercise on sleep in an adult population.”
Dr. Brellenthin continues, “Although there is no disputing the fact that aerobic exercise promotes sleep, we were astonished to find in the study that the effects of weight training exceeded those of aerobic exercise.”
The research conducted by Dr. Brellenthin and her colleagues comprised a total of 386 individuals who, according to their body mass index, were either overweight or obese.
Participants of the study were leading sedentary lifestyles and had high blood pressure.
The researchers randomly allocated the participants into one of four groups:
- A no-exercise group
- A cardio-only group
- A strength training-only group
- A cardio and strength training group
The participants were given the task of exercising three times a week, each session lasting one hour, and all the sessions were under the supervision of the researchers.
Workouts included running on treadmills, riding stationary bikes, and using elliptical machines for those in the cardio group. While for strength training, the participants used twelve resistance machines to work on the main muscle groups.
The participants were able to track their activity with the aid of a key fob which they connected to each piece of exercise equipment. This key fob also allowed the researchers to monitor the participants’ heart rates and other vital information.
The researchers assessed participants’ sleep at the beginning of the study and 12 months after the start of the exercise program. The findings indicated that 35 percent of the study participants had difficulties sleeping at the beginning.
After a year, everyone, on average, stated that they had slept better. However, the results showed that the participants in the strength training group who had poor sleep (less than 7 hours) before the start of the study had an improvement of 42 percent in their sleep, sleeping an additional 40 minutes on average.
The participants in the cardio-only group had an additional 23 minutes of sleep. In comparison, those in the group who completed both exercises and originally had trouble sleeping had an additional 17 minutes of sleep. Furthermore, the control group also reported sleeping an additional 15 minutes.
Additionally, the results showed that those who only did strength training experienced more significant improvements in other sleep metrics.
Strength training and a combination of cardio and strength exercise increases sleep efficiency (the amount of time you sleep while in bed). Also, lifting weights reduced the time it takes to fall asleep by roughly three minutes. For the other groups, there were no significant changes in these measures.
Why Strength Training is Better than Cardio
The exact reason why strength training improves sleep better than cardio is not evident to scientists at the moment. However, some scientists have provided some plausible explanations.
According to Dr. Brellenthin, weight training causes muscle adaptation, which causes the muscles to produce more testosterone and growth hormones.
Both of these hormones are connected to improved sleep quality. “Sleep is responsible for the much-needed physical restoration that occurs in our bodies.”
Dr. Brellenthin continues, “Because strength training is taxing on the muscles and requires more recovery than cardio alone, it is possible that this encourages one’s body to sleep more intensely or for longer throughout the night.”
Other studies corroborate the findings of Dr. Brellenthin’s research. A study published in the preventive medicine journal suggests that cardio and strength training effectively improve sleep duration and quality.
How to Improve your Sleep with Exercise
It is crucial to note that both cardio and strength training exercises can improve your sleep. However, you should try strength training if you want an extra boost. Here are some ways you can boost your sleep with exercise. They include:
- Get at least 30 minutes of exercise five days a week. According to the Physical Activity Guidelines for Americans published by the United States Department of Health and Human Services, adults should exercise for around 150 minutes per week, equivalent to 30 minutes on five days of the week. You can exercise at the gym, take a walk or engage in sporting activities. Whatever you do, make sure you burn the excess calories.
- Up the ante with strength training: Lifting dumbbells might be what the doctor ordered for your sleep. Make sure you start slowly and with a lesser weight load.
- Don’t exercise close to your sleep time: While some studies suggest that exercising close to your bedtime may not affect your sleep, most scientists believe exercising close to your bedtime may harm your sleep.  Remember, avoid strenuous activities close to your sleep time.
- Brellenthin, A. G., & Lee, D. C. (2022). Abstract 038: Comparative Effects Of Aerobic, Resistance, And Combined Exercise On Sleep. Circulation, 145(Suppl_1). https://www.abstractsonline.com/pp8/?_ga=2.43661667.795188704.1646150369-78844285.1609356599#!/10553/presentation/99
- Dolezal, B. A., Neufeld, E. V., Boland, D. M., Martin, J. L., & Cooper, C. B. (2017). Interrelationship between Sleep and Exercise: A Systematic Review. Advances in preventive medicine, 2017, 1364387. https://doi.org/10.1155/2017/1364387
- Physical Activity Guidelines for Americans 2nd Edition … – Health. https://health.gov/sites/default/files/2019-09/Physical_Activity_Guidelines_2nd_edition_Presentation.pdf.
- Stutz, J., Eiholzer, R., & Spengler, C. M. (2019). Effects of Evening Exercise on Sleep in Healthy Participants: A Systematic Review and Meta-Analysis. Sports medicine (Auckland, N.Z.), 49(2), 269–287. https://doi.org/10.1007/s40279-018-1015-0
- Myllymäki, T., Kyröläinen, H., Savolainen, K., Hokka, L., Jakonen, R., Juuti, T., Martinmäki, K., Kaartinen, J., Kinnunen, M. L., & Rusko, H. (2011). Effects of vigorous late-night exercise on sleep quality and cardiac autonomic activity. Journal of sleep research, 20(1 Pt 2), 146–153. https://doi.org/10.1111/j.1365-2869.2010.00874.x