Exercise training improves daytime functioning in sleep apnea patients

Exercise may improve obstructive sleep apnea (OSA) severity, even in the absence of weight loss. The less severe the OSA, the better patients may feel in the daytime. This article in the August edition of the Journal of Clinical Sleep Medicine is about a study done to see if exercise training can improve daytime functioning even without reducing OSA severity.

In the study, they had a group of people do supervised exercise for 12 weeks versus the control group that did only stretching for 12 weeks. The two groups of participants were similar with the exception of their baseline sleepiness scores, with the exercise group reporting a little more sleepiness than the stretching group.

The results of the study showed that at the end of the 12 weeks, the OSA severity was 25% lower in the exercise group. The exercise group also had less depressive symptoms, less fatigue, and more vigor than the stretching group. Exercise training caused a lowering if subjective sleepiness, but this was not statistically significant. Exercise training improved physical functioning, vitality, and mental health as measured by questionnaires. Interestingly, there was no difference in participants performance on tests of cognition with exercise versus stretching.

Now you may say that the improvements in exercise were due to OSA severity reduction, not because of the exercise itself as the authors proposed. But, only improvement in fatigue was linked to reduction in OSA severity in the exercise group. All of the other improvements occurred in the exercise group even when the OSA severity remained the same.

These findings are exciting, because not everyone feels better on CPAP. Perhaps exercise may improve their functioning, even though they still have OSA.

Exercise and Obstructive Sleep Apnea

A few, small studies have shown that regular exercise can reduce the severity of obstructive sleep apnea (OSA) as determined by the number of times the upper airway collapses per hour of sleep (AHI). There is an article in the Journal Sleep where researchers studied the effect of a 12 week moderate-intensity exercise program on the AHI in patients with OSA.

There were 43 study participants, ages 18-55 years old with at least moderate severity OSA and who were overweight with a body mass index of >25. The participants also were sedentary, on stable medication dosages, and not being treated for OSA. At baseline, participants had an overnight sleep study, evaluation of body fat composition, pulmonary function tests, and respiratory muscle strength testing. They also wore a home sleep study wrist watch, called an actigraph, for about a week. The participants were then randomized to 12 weeks of exercise training including resistance and aerobic components, or to a stretching only control group. The baseline measurements were than repeated after completion of the 12 weeks.

Results showed that when compared to the stretching only control group, exercise training did moderately improve the AHI. More specifically, 25% were considered a treatment success (based on AHI reduction of at least 50%) and 63% reduced their AHI by at least 20%. And these reductions in OSA severity occurred despite no change in body weight. However, the exercisers did reduce their fat composition by over 1%. Since overweight individuals with OSA can have extra fat in their neck that contributes to upper airway collapse, a reduction in neck fat could explain how the exercisers reduced their OSA severity despite not losing any weight.