Exercise helps avoid hypoxia, preserve brain metabolism and cognition in OSA

By preventing hypoxia, exercise training (ET) can help improve the cerebral metabolic rate and cognitive function in patients with moderate to severe obstructive sleep apnoea (OSA), a recent study has found.

Researchers randomly allocated OSA patients to receive either ET (n=23; three times per week) or to a no-intervention control group (n=24). All participants underwent brain magnetic resonance imaging, polysomnography, ¹⁸F-fluoro-2-deoxy-d-Glucose positron emission tomography, and cardiopulmonary exercise testing, as well as accomplished a cognitive battery.

Patients in the exercise group saw a significant decline in the apnoea-hypopnoea index (AHI; change, –5.36 events per hour, 95 percent confidence interval [CI], –10.48 to –0.44), an effect that was absent in controls. Similarly, substantial, but not significant, improvements were reported in other sleep parameters such as arousal index and oxygen desaturation.

Similarly, peak oxygen uptake was likewise significantly improved in the exercise group (change, 4.07, 95 percent CI, 2.82–5.31).  

Of note, the researchers also reported significant hypermetabolism in the right frontal lobe among those who underwent ET, as expressed by a significant increase in the cerebral metabolic glucose rate (CMRgl; p<0.05). Such an increase was observed to be inversely correlated with obstructive AHI (r, –0.43; p<0.01) and arousal index (r, –0.53; p<0.05).

Moreover, the ET group also saw significant improvements in cognitive function as assessed by the Frontal Assessment Battery, Trail Making Test-B, and Stroop Color Word Test.

“In sedentary patients with moderate to severe OSA, ET is associated with improvement not only in exercise capacity and OSA severity but also increased CMRgl, attention/executive functioning. Such exercise intervention may decrease the risk of developing cognitive decline in patients with OSA,” the researchers said.