Many of us have heard that exercise can help improve sleep, but this advice can often come with its own set of questions. How much exercise do we need? What type of exercise should we be getting, and when should we be exercising?
A study published in the BioMed Research International journal recruited 21 individuals with chronic primary insomnia. Five of the participants were men and 16 were women, with an average age of 45.
Each insomniac underwent a four-month program of moderate aerobic exercise. After exercising, individuals saw a reduction in symptoms of depression, lower cortisol levels, and their immune response improved.
Furthermore, exercise increased REM sleep and overall sleep time.
What exercise was undertaken in this study?
Participants in this study exercised on a treadmill three days a week. They exercised on the treadmill for an additional 50 minutes from when they found talking to be uncomfortable due to the increase in their breathing rate (this is also known as the VT1, or First Ventilatory Threshold).
When did participants exercise?
Exercise took place randomly throughout the four weeks, either within an hour on either side of 10 AM or within an hour on either side of 6 PM.
What were the results?
By the end of the study, participants:
- Fell asleep approximately 14 minutes faster than prior to the study
- Got roughly 24 minutes more sleep each night
- Enjoyed a 7 percent improvement in sleep efficiency
- Entered REM sleep approximately 24 minutes faster than they usually did
- Spent approximately 15 fewer minutes awake during the night
It wasn't just sleep that improved, either. After the exercise training, participants saw a 30 percent drop in their Beck Depression Inventory score. In other words, the exercise regimen had reduced depression symptoms, too.
Finally, there was evidence of improvement in each individual's immune response, as well.
Why does exercise improve sleep?
As cited in realier Health Central posts on sleep disorders, some cases of insomnia appear to be caused, at least in part, by hyperarousal. The anxiety-reducing effects of exercise may help counter this hyperarousal, thus improving sleep.
Those with chronic insomnia often have elevated cortisol levels. Exercise has been found to reduce the amount of cortisol in the blood, which may also explain why regular exercise improves sleep.
Exercise also reduces the body's inflammatory response. It is thought that chronic inflammation can lead to insomnia. Those who do not get enough sleep often have higher levels of inflammatory messengers in the body.
No, you don't need a treadmill
If you don't have a treadmill, don't feel disheartened! Simply target at least 150 minutes of moderate-to-vigorous exercise each week. If you like to walk, moderate exercise (for most people) would require a pace of roughly 100 steps per minute.
Try to avoid exercising in the three hours before bedtime. If you exercise too close to bedtime, your body temperature may still be elevated by the time you're in bed, which can make sleep more difficult.
If the only free time you have available for exercise is late at night, try a lighter form of exercise such as yoga and take a bath or shower just before bed to help your body temperature fall more quickly. Finally, snack on some quality carbohydrates after nighttime exercise to help boost levels of tryptophan and serotonin.
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Passos, Giselle Soares, Dalva Poyares, Marcos Gonçalves Santana, Alexandre Abílio de Souza Teixeira, Fábio Santos Lira, Shawn D. Youngstedt, Ronaldo Vagner Thomatieli dos Santos, Sergio Tufik, and Marco Túlio de Mello. "Exercise Improves Immune Function, Antidepressive Response, and Sleep Quality in Patients with Chronic Primary Insomnia." BioMed Research International 2014.2014 (2014). Accessed May 31, 2016.