Dear Doctor: A CPAP machine helped one patient sleep through the night — here's the science behind why

Dear Doctor Roach: I’m writing regarding the recent column that mentioned frequent nighttime urination. I had a similar problem and awakened several times to urinate each night. About a year ago, I started using a CPAP for sleep apnea.

Immediately after starting to use the CPAP, my nighttime urination frequency decreased. It’d range from sleeping completely through the night to waking up twice, with an average of waking up once per night.