Deep sleep linked to blood pressure risk30th August 2011
Researchers in the United States say a poor night's sleep could increase the risk of high blood pressure, especially in older men.
The Harvard-led team said that slow-wave sleep, also known as deep sleep, was particularly important to maintaining health.
Men who had clocked up the lowest level of deep sleep had an 80% higher risk of developing high blood pressure, according to the study, which was published in the journal Hypertension.
The connection was still strong, even when other factors like obesity or length of sleep were taken into account.
Sleep researchers at the Brigham & Women's Hospital, Beth Israel Deaconess Medical Center and Harvard Medical School, said reductions in slow-wave sleep were associated with the highest risks to health.
Study lead author Susan Redline said the risk of hypertension was the clearest.
Previous research has suggested that sleep problems are associated with a raised risk of obesity and cardiovascular problems, among other problems.
The researchers studied a total of 784 men, with an average age of 75, who had enrolled in the Outcomes of Sleep Disorders in Older Men Study.
None of the men had blood pressure readings higher than 120/80 when they were first assessed in 2003-05.
But on a follow-up visit in 2007-09, 243 of the men were found to have developed high blood pressure.
They were then sorted into four groups, ranging from the group with the highest amount of deep sleep to the group with the lowest amount of deep sleep.
The link between slow-wave sleep and hypertension was clear, even when factors like age, race and body mass index were discounted.
Sleep-disordered breathing and overall sleep length had little impacdt on the association, the researchers said.
Redline said the results were of particular concern for older people, because slow-wave sleep decreased with age.
Healthy adults generally can expect to enjoy around 25% deep sleep in a night, whereas children typically sleep deeply for 40% of their total night's sleep.
The older men studied enjoyed an average of just 11.2% slow-wave sleep, with those in the lowest deep sleep groups getting less than 4%.
Older men tend to get less deep sleep than older women, previous studies have shown.
However, researchers cautioned against assuming a causal relationship between lower levels of deep sleep and high blood pressure.
According to Miami-based sleep clinician Alberto Ramos, experts agree that not enough sleep over time can also boost the risk of high blood pressure.
Ramos said the new study was important because it suggested that quality of sleep was just as important quantity, if not more so.
He and Redline said the reasons for this were still unclear.
Blood pressure normally falls during sleep, especially during deep sleep. If there is not enough deep sleep, it is possible that the blood pressure does not have enough opportunity to keep itself at a healthy level.
Redline suggested that adults try to minimise interruptions to their nightly sleeping patterns, because anything that wakes a person repeatedly will affect the amount of deep sleep they enjoy.
Treatment for sleep disorders like sleep apnoea might alleviate the problem, Redline suggested.
Ramos said that while weight was not necessarily a factor in the link between deep sleep and high blood pressure, the study subjects in the lowest deep-sleep groups tended to be heavier than the others.
He said maintaining a healthy weight might also boost the amount of deep sleep a person had.
Share this page
There are no comments for this article, be the first to comment!
Post your comment
Only registered users can comment. Fill in your e-mail address for quick registration.
Title: Deep sleep linked to blood pressure risk
Author: Luisetta Mudie
Article Id: 19581
Date Added: 30th Aug 2011