Insomnia affects about a third of all peopleat some point in their life and it makes it difficult to either fall asleep or stay asleep.
Sometimes it’s a mild, short-term symptombut if it’s severe and lasts a long time it’s considered a disorder.
Either way, it leaves the person feeling exhausted.
Unfortunately, treating insomnia is challenging.
For example, sleep medications often havedangerous side-effects and can be habit forming, so they’re generally recommended for temporaryuse only after other options have been tried.
Another treatment is cognitive behavioraltherapy, which is effective, but requires clinical supervision which costs time andmoney.
This is where exercise comes in.
Exercise is safe, can be done quickly andcheaply, and doesn’t require the help of a highly trained clinician.
Also, exercise has been shown to improve sleepquality in a number of studies, and that’s why exercise is a core recommendation fromthe National Sleep Foundation to improve sleep.
That said, while there are a number of clearbenefits to exercise, only a few studies have looked at the relationship between physicalexercise and insomnia, so whether or not exercise improves sleep for people with insomnia remainsunclear.
To answer this question researchers lookedat a number of studies that explored the link between exercise and symptoms of insomniaor insomnia disorder.
They specifically looked at randomised clinicaltrials, where at least 30 minutes of either aerobic exercise, like cycling, or mind-bodyexercise, like yoga or Tai chi, were done per session, for at least 120 total minutesa week for several weeks, to see if that improved overall sleep in adults with insomnia.
To measure sleep quality, the studies eitherused subjective data, like questionnaires and diaries or objective data, like actigraphy,which measures body movement through the night, or polysomnography, which measures brain waves,heart rate, and breathing through the night.
So what did they find? Well, let’s start with studies on individualswith mild or short-term insomnia symptoms.
Four out of five studies that used subjectivedata, found that exercise improves sleep while the fifth study showed no difference betweenthe exercise and the control group.
There was no clear difference between aerobicand mind-body exercise in these studies.
Similarly, two of the three studies that usedobjective data, found that exercise improves sleep.
Interestingly, the study that didn’t showan improvement based on objective data did show an improvement based on subjective datathat was collected in the same study.
Now, let’s switch and look at studies onindividuals with the more severe insomnia disorder diagnosis.
Four out of five studies that used subjectivedata found that exercise helps, and again there wasn’t a clear difference betweenaerobic or mind-body exercise.
On the other hand, all of the five studiesthat used objective data, found that exercise had no effect on insomnia disorder.
So where does that leave us? Well, to start out, this review is based ona relatively small number of studies that had small samples sizes—so the power wassmall—meaning that it can be hard to detect the effect of exercise and insomnia if thateffect is small.
Nevertheless, individuals with mild or short-terminsomnia symptoms showed a benefit from exercise, and people with insomnia disorder reportedbenefitting as well, although the objective data for them doesn’t reflect that.
In this case, perhaps the exercise is causingan improvement in mood or energy levels so that they’re not as affected by the insomniaas much, or perhaps the benefit was small and went undetected given the low power ofthe study.
Regardless, the fact that people reportedfeeling better in terms of their insomnia symptoms probably justifies including exerciseas part of the management strategy for anyone with insomnia.
That said, while there are several hypothesesfor why exercise helps improve insomnia the mechanism is not well understood.
Therefore, several questions remain like isthere an optimal type of exercise or duration of exercise that should be done to improvethe symptoms of insomnia? More study is needed to make such recommendations.