Obstructive sleep apnoea is characterised by repeated partial or complete collapse of the upper airway during sleep, producing brief cessations of breathing, drops in blood oxygen saturation, and micro-arousals that fragment sleep architecture without the individual consciously waking. Moderate to severe sleep apnoea, defined as 15 or more breathing events per hour, affects approximately 17 percent of middle-aged men and 9 percent of middle-aged women in population studies. The majority of cases are undiagnosed.
The Cardiovascular Consequences
Each apnoeic episode produces a surge of sympathetic nervous system activity, raising heart rate and blood pressure acutely. Over hundreds of events per night, this repetitive cardiovascular stress produces durable increases in 24-hour blood pressure, ventricular remodelling, and elevated inflammatory markers. Adults with untreated moderate to severe sleep apnoea have approximately three times the risk of hypertension, two to four times the risk of atrial fibrillation, and significantly elevated risk of stroke and heart attack compared to matched adults without apnoea.
Beyond Snoring: The Symptoms That Are Missed
- Excessive daytime sleepiness despite what appears to be adequate sleep time
- Waking with headaches, particularly in the morning
- Difficulty concentrating and cognitive fog during the day
- Nocturia: waking to urinate once or more per night is often apnoea-driven rather than bladder-driven
- Mood changes, irritability, and low motivation that do not respond to other interventions
- Paradoxical insomnia: difficulty returning to sleep after micro-arousals caused by apnoeic events
- Partners observing stopped breathing, gasping, or choking sounds during sleep
Sources
- Young, T., et al. (2008). Sleep disordered breathing and mortality: eighteen-year follow-up of the Wisconsin Sleep Cohort. Sleep, 31(8), 1071-1078.
- Punjabi, N.M. (2008). The epidemiology of adult obstructive sleep apnea. Proceedings of the American Thoracic Society, 5(2), 136-143.
- Somers, V.K., et al. (2008). Sleep apnea and cardiovascular disease. Journal of the American College of Cardiology, 52(8), 686-717.