Prevalence of nocturnal hypoxaemia amongst men with mild to moderate hypertension.

Thirty men (aged 35-65) with untreated essential hypertension (BP greater than or equal to 140/90), confirmed by 24-h ambulatory monitoring, had overnight recordings of arterial oxygen saturation (SaO2) in their own homes. The overnight saturation records were compared with those from a group of 30 normotensive control subjects matched for age, height and weight. The groups did not exhibit significant differences in any of the following parameters of overnight oxygenation: median SaO2, lowest SaO2 or frequency of 3 or 4 per cent dips in SaO2. We conclude that essential hypertension is not associated with excessive arterial hypoxaemia such as might be due to a sleep apnoea syndrome.