Fung et al Show That Lack Of Deep Sleep Can Lead To Hypertension

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Are you getting enough deep sleep?

Recent research by Fung et al indicates that the inability to get deep sleep at night may cause hypertension. As reported in New York Times, the study titled, Decreased Slow Wave Sleep Increases Risk of Developing Hypertension in Elderly Men and published in the journal Hypertension, shows that people who do not get enough deep sleep at night may be at a higher risk of hypertension. This is the first study that connects quality sleep (or the lack of it) to high blood pressure.

Details of the Research Study

Fung et al aimed at studying the slow-wave stages of sleep. In a normal person, this would constitute about 90 minutes to 120 minutes of deep sleep; i.e. about 25% of 1 night’s sleep.
The researcher’s at Harvard Medical School followed 784 healthy men as part of the sleep study. These men did not have high blood pressure at the beginning of research.
The men were monitored at various times by checking their blood pressure and levels of slow-wave sleep during the course of 3.5 years of study. A machine monitored their slow wave sleep at home.

Results of the Study

Men who had least amount of slow-wave sleep had higher risk of developing high blood pressure.
These men enjoyed only about 4% slow-wave sleep at night.
Men who had less deep sleep were also prone to sleep apnea and less overall sleep.

Discussion

Dr Susan Redline, an author of the study and professor of sleep medicine at Harvard Medical School feels that even though the study was performed only on men, the results would hold true for women too who do not get enough deep sleep.

She explains that during deep sleep, a person’s heart rate, adrenalin levels, brain’s electrical activity, and blood pressure slows down. There is a drop in blood pressure of about 10mm of mercury when slow-wave sleep sets in. When there is no drop or dip in blood pressure as in people who do not get enough deep sleep, the risk factor for heart disease increases. This ‘nondipping’ of blood pressure at night can influence blood pressure during the day as well and it may even interfere with brain signals controlling blood pressure.

Deep sleep at night can be affected by various factors such as sleep apnea, loud snoring, medications, physical activity during the day, age etc. People who feel tired even after a night’s sleep (7 to 8 hours of sleep) may do better on meeting a sleep specialist.