Melanie Hoffmann, Editor-in-Chief

February 5, 2024, 6:23 pm | Read time: 5 minutes

Sleep disorders have long become a widespread issue. In Germany, around 80 percent of adults feel affected, with 20 percent suffering from severe problems falling or staying asleep. This is according to the health report of a large German health insurance company. The situation is similar in other countries. For some affected individuals, only sleep-inducing medications help with their complaints. However, it’s better to treat sleep disorders naturally–without pills. One method is to engage in regular and sufficient exercise. Researchers from Norway have now shown in a study that it’s not just about the exercise itself, but about the level of physical fitness.

How are physical fitness and sleep related?

Researchers at the Norwegian University of Science and Technology wanted to know if there is a connection between physical fitness and good or poor sleep. They used the Norwegian long-term study Trøndelag Health Survey (HUNT), which has involved about 240,000 people since its start in 1984. For their project, the scientists studied 34,357 participants from the third round of the HUNT long-term study. These participants were on average 51 years old, recruited between 2006 and 2008, and observed for about ten years.

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Study procedure

The scientists applied a special algorithm to the data of these individuals to determine their physical fitness, specifically their cardiorespiratory fitness. They also drew information from the National Norwegian Prescription Database. This allowed them to draw conclusions about the use of prescription medications. Based on the number of prescribed sleep medications, the study leaders recorded which and how many people developed sleep disorders.¹ The determination of sleep complaints was thus based on medical diagnoses and not on self-reports from the participants.

What is cardiorespiratory fitness?
Sports enthusiasts are likely familiar with the measure VO₂max. The VO₂max value is often used to determine running performance and indicates cardiorespiratory fitness. Another term for cardiorespiratory fitness is “general dynamic aerobic endurance capacity.” It is considered an important health marker because it shows how well the respiratory and circulatory systems supply the body with oxygen. It is good when the lungs, heart, blood vessels, and muscles work together ideally.

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Better physical fitness apparently reduces the risk of sleep disorders

“Almost 5,800 participants received their first prescription for a sleep aid during the study period,” explains Professor Linda Ernstsen, who was involved in the study, in a press release.² Seventeen percent of the study participants developed such severe sleep disorders that their doctor prescribed them medication.

The further analysis by the scientists also revealed the role physical fitness seems to play. The fittest participants needed the least sleep medication. Physical fitness, the researchers interpret, seems to be a factor that can positively–or if fitness is not so good, negatively–influence sleep. This effect appears to be somewhat stronger in men than in women. The fittest man in the study had a 15 percent reduced risk of sleep disorders severe enough to require a sleep aid.

“The corresponding percentage risk for the fittest women was much lower. But women who have sleep problems can also benefit from getting in better shape,” Ernstsen explains. “Our results support the idea that improving or maintaining fitness can be an effective alternative to prevent sleep problems.”

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More on the topic

Oxygen as a Fountain of Youth? What Longevity Has to Do With Lung Health

By up to 16 percent Simple Dietary Rule Improves Sleep the Same Night

Physical activity and fitness affect sleep quality

A 2021 study also examined the relationship between physical activity and fitness regarding their impact on sleep quality. Seventy-four middle-aged adults with low physical activity were studied. Nearly 40 percent of participants were found to have poorer sleep quality, attributed to a lack of exercise.

It was also shown that increased physical activity can potentially help reduce sleep disorders. This would also positively affect physical and mental health and generally improve the aging process.³

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Treat sleep disorders naturally–with the right training

Those who suffer from sleep problems can help themselves by improving their physical–specifically, cardiorespiratory–fitness. Generally, any movement is better than none. But according to research, endurance-oriented training that engages at least one-fifth of the skeletal muscles is most effective for maintaining or improving cardiorespiratory fitness. This includes sports like running, cycling, or swimming. These can be natural ways to prevent or treat sleep disorders if they already exist.

Sources^4,5,6,7,8,9