When you’re exhausted, starting a new exercise routine may sound like a nightmare, but a new study suggests getting active could be the secret to a good night’s sleep.

Scientists in China reviewed existing clinical trial data and found that certain forms of exercise, including yoga and jogging, that appeared to help people sleep longer at night. The findings suggest physical activity should be considered as a frontline treatment for insomnia, the researchers said.

“The most important takeaway from this research is that we can confidently tell people with insomnia, ‘Exercise really can help you sleep better,'” lead study author Zhi-jun Bu told Gizmodo.

Bu and his colleagues were inspired by the idea of “green prescriptions,” which are essentially interventions for physical and mental health that involve exercise or nutrition. They focused on insomnia because it’s both common and debilitating. More than half of American adults are believed to have experienced difficulty sleeping, while a recent survey from the American Academy of Sleep Medicine found that 12% of U.S. adults have been diagnosed with chronic insomnia.

The researchers analyzed data from 22 clinical trials involving more than 1,300 participants and 13 different interventions for insomnia, including cognitive-behavioral therapy, seven forms of exercise, and so-called active controls, like stretching or being given lifestyle advice.

As the researchers had expected, people who received CBT saw significant improvements in their sleep quality and duration, as did those who practiced Tai Chi, yoga, and walking or jogging. Of these, yoga was linked to almost two hours of extra sleep compared to controls, while walking or jogging was tied to a significant reduction in the severity of people’s self-reported symptoms. And Tai Chi apparently provided the most benefits for sleep of all the exercises tested.

The findings were published Tuesday in the journal BMJ Evidence-Based Medicine. Bu conducted the study while a researcher at the Beijing University of Chinese Medicine’s Center for Evidence-Based Chinese Medicine; he’s now pursuing a doctorate at The Affiliated Hospital and Clinical Medical College of Nanjing University of Chinese Medicine.

The analysis is promising, but it has limitations. Some of the trials included were of lower quality than others. But there is other evidence to suggest that exercise can promote rest; a study published earlier this month found that daily exercise was associated with deeper, more restorative sleep. It’s also unclear why physical activity can help us doze off, but the researchers have some theories.

“Yoga incorporates breath control and meditation, which helps regulate the autonomic nervous system and reduce anxiety and stress. Tai Chi, as a mind-body practice combining physical movement and mental focus, may enhance parasympathetic activity, reduce inflammatory responses, and promote brain plasticity and circadian rhythm regulation,” Bu explained.

“Aerobic exercises such as walking or jogging may improve sleep structure by increasing energy expenditure, enhancing melatonin secretion, lowering cortisol levels, and boosting the proportion of deep sleep,” he added. 

Other questions remain unanswered: There’s no established optimal “dose” of physical activity for insomnia, and the timing of our exercise could be crucial, too. A study published in April found that performing intense workouts up to four hours before bed could disrupt sleep, for example. Some individuals might also benefit most from specific forms of exercise. Yoga and Tai Chi might be best for people who don’t sleep enough, while aerobic exercise might work best to reduce people’s daytime sleepiness and fatigue, Bu said.

“Overall, exercise is a natural sleep aid with low side effects, low costs, and high accessibility, making it especially suitable for promotion in primary healthcare and community health settings,” Bu said.