Jun 11 2012
By Ingrid Grasmo
Individuals who sleep for 5 hours or less each night are at increased risk for developing hypertension, suggest study findings.
A large body of evidence from laboratory and population-based studies confirms the association between sleep loss and negative cardiovascular health outcomes.
However, until now, Damien Leger (Paris Descartes University, France) and colleagues say, little was known about the association between sleep duration and hypertension in primary health settings.
To investigate, the team measured blood pressure (BP), took blood samples, and administered standardized health and sleep questionnaires to 1046 French adults, aged on average 55.5 years, who visited a general practitioner at a primary care center in Paris.
Hypertension was defined as having either a systolic BP (SBP) of 140 mmHg or more or diastolic BP (DBP) of 90 mmHg or more, or by the use of antihypertensive medications. Sleep duration was recorded as the self-reported average number of hours of sleep per night during the week.
The researchers report that 42% of individuals were diagnosed as having hypertension, with 34.5% on antihypertensive medication, 28.5% with elevated SBP and DBP, 32.9% with elevated SBP alone, and 4.1% with only elevated DBP.
A sleep duration of less than 7 hours per night was reported in 43.9% of individuals, of whom 14.3% slept less than 6 hours per night.
When the researchers analyzed BP according to sleep category duration among patients not taking antihypertensive medications, they found significant differences in DBP between certain groups. Indeed, those who slept 5 hours or less per night had a higher DBP, at 82.2 mmHg, than those who slept 6 hours, 7 hours, or 9 or more hours per night, with DBPs of 78.6, 80.2, and 78.6 mmHg, respectively.
No significant differences were seen for SBP among the groups.
Furthermore, the prevalence of hypertension increased significantly in line with decreasing sleep hours, from 32.9% for those sleeping 9 hours or more to 51.0% for those sleeping 5 hours or less per night.
Regression analysis showed that individuals who slept 5 hours or less per night had a 1.80-fold increased odds for hypertension compared with individuals sleeping 7 hours, after adjusting for confounders.
Writing in the Journal of Hypertension, the researchers conclude: "Individuals in midlife reporting an average sleep duration of 5 hours or less at night should be considered as an additional higher risk group for adverse cardiovascular events."
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