This big study looked at over 13,000 adults to see if sleep apnea goes hand-in-hand with losing muscle. People with sleep apnea had about 85% higher chances of having less muscle than those without the breathing problem. This connection was very clear when doctors used special machines to check sleep instead of just asking questions.
The link was even stronger in older adults who were 64 years or older. It was also much more common in people from Asian countries. When doctors used simple questionnaires to check for sleep issues, the connection looked weaker. This suggests that better testing tools help find the real problem.
We cannot say that sleep apnea definitely causes muscle loss because the studies did not follow people over time. Different doctors used different rules to define both conditions. Even so, the results show that adults with sleep apnea should talk to their doctors about keeping their muscles strong.