04 December 2014

Sleep apnoea may lower your aerobic fitness

People with this sleep disorder take in less oxygen during exercise, small study finds.


People with sleep apnoea may have lower levels of aerobic fitness, a new study suggests.

Read: Family docs can treat simple sleep apnoea

Sleep apnoea
causes the upper airway to become blocked by soft tissue in the back of the throat during sleep.

This causes pauses in breathing and other symptoms, such as gasping and snoring.

Study variables

The research included 15 adults with moderate to severe obstructive sleep apnoea and a comparison group of 19 adults with mild or no apnoea.

They pedalled a stationary bike at increasingly harder resistance levels – similar to climbing up a progressively steeper hill – and kept going until exhaustion.

On average, people in the sleep apnoea group scored 14 percent lower on a test that measures the maximum amount of oxygen a person can take in during intense exercise.

This measurement is called VO2 max.

More likely to be obese

People with sleep apnoea are more likely to be overweight or obese, and thus less fit, the researchers noted.

However, they found that people with sleep apnoea had poorer aerobic fitness than those in the comparison group, even if they were the same body size.

Although this study found an association between lower oxygen intake during activity and sleep apnoea, it wasn't designed to prove that sleep apnoea was the definitive cause of this difference.

Read: No apparent link between sleep apnoea and cancer

Results of the study were published in the Journal of Clinical Sleep Medicine.

"Encouraging patients to exercise more is part of the story, but that is not the whole story," lead author Dr. Jeremy Beitler, assistant clinical professor in pulmonary and critical care medicine at the University of California, San Diego School of Medicine, said in a university news release.

"We believe the sleep apnoea itself causes structural changes in muscle that contributes to their difficulty exercising," he added.

Read: A fat tongue may be disrupting your sleep

The researchers said measuring VO2 max may help identify sleep apnoea patients at increased risk for heart attack and stroke, which could encourage earlier treatment of sleep apnoea, which is underdiagnosed and often untreated.
Read More:

Can sleep apnoea affect your sex life?
Sleep apnoea tied to memory problems
Sleep disorders increase during pregnancy

Image: Man with sleep apnoea from Shutterstock.




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