Not getting enough oxygen at night and the release of certain hormones are thought to be some reasons why people with OSA wake up regularly to use the bathroom at night (via Sleep Apnea.org). Nocturia is prevalent in about 50% of people with this sleep disorder.
According to Dr. Brandon R. Peters, a sleep medicine specialist at Pulmonary and Sleep Associates of Marin in Novato, California, the connection between the need to pee frequently at night and OSA is an often-neglected one, even in medical circles (per HuffPost). People often turn to explanations like an enlarged prostate, consuming too much water before bed, a hyperactive bladder, incontinence, and menopause as reasons, but overlook this important medical condition.
“The body normally releases anti-diuretic hormone (ADH) in sleep to prevent needing to wake to urinate. It works to shut down the kidneys, preventing movement of fluids from the blood vessels to the bladder,” explained the sleep medicine specialist. For people with OSA, this hormone release is disrupted, leading to more pee accumulating in the bladder and the need to urinate several times in the night.