Does sleep apnea cause high blood pressure even if I feel fine?

Untreated obstructive sleep apnea causes hypertension through a mechanism independent of how you feel during the day: each apnea event triggers a sympathetic nervous system surge that drives blood pressure up transiently, and in moderate-to-severe OSA with 30+ events per hour, these surges happen hundreds of times per night, maintaining elevated sympathetic tone into the daytime and producing sustained hypertension in approximately 50% of men with untreated OSA (Peppard et al., NEJM, 2000).

Men with sleep apnea often have "resistant hypertension", blood pressure that fails to respond adequately to two or three antihypertensive medications. In clinical practice, resistant hypertension in a middle-aged man with a thick neck, nighttime snoring reported by a partner, and daytime fatigue should trigger an immediate sleep study. The hypertension is not primary; it is secondary to a mechanical airway obstruction that is solvable. Treating the sleep apnea is more important in this scenario than adding a fourth blood pressure medication.

Honesty Scale: Solid (1). The sleep apnea-hypertension causal relationship is one of the strongest in sleep medicine epidemiology.

What to do: If you have hypertension that is difficult to control, ask your physician whether you have been screened for sleep apnea. If you have not, request a home sleep study. The specifics matter: neck circumference above 17 inches, Epworth Sleepiness Scale score above 10, and partner-reported apneas are the three strongest clinical predictors of moderate-to-severe OSA in men.

For the full picture, read The Sleep Architecture Deep Dive

## Category 3: Sleep Hygiene