Sleeping less than seven hours is associated with an increased risk of developing high blood pressure over time, according to a study presented at the Annual Scientific Session of the American College of Cardiology.
While the connection between sleep patterns and high blood pressure has been previously reported, researchers noted that evidence about the nature of this relationship has been inconsistent. The current analysis gathers data from 16 studies conducted between January 2000 and May 2023, which evaluated the incidence of hypertension in 1,044,035 people from six countries who had no history of high blood pressure over a median follow-up of five years (with follow-up periods ranging from 2.4 to 18 years).
Short sleep duration was significantly associated with an increased risk of developing high blood pressure after adjusting for demographic and cardiovascular risk factors, including age, gender, education, BMI, blood pressure, smoking, etc. Additionally, the association was even stronger for those who slept less than five hours.
"According to the most up-to-date data, the less you sleep (i.e., fewer than seven hours a day), the more likely you are to develop high blood pressure in the future," said Dr. Kaveh Hosseini, assistant professor of cardiology at the Tehran Heart Center in Iran and the study’s lead researcher. "We saw a trend between longer sleep duration and a higher incidence of high blood pressure, but it was not statistically significant. Sleeping seven to eight hours, as recommended by sleep experts, may also be best for the heart."
The study found that sleeping less than seven hours was associated with a 7% increase in the risk of developing high blood pressure, which rose to 11% when sleep duration was less than five hours. In comparison, diabetes and smoking are known to increase the risk of hypertension by at least 20%, Hosseini noted.
While the study didn’t examine why this might be the case, Hosseini suggested that sleep disruption could be the culprit. For example, lifestyle habits or comorbid conditions such as overeating, alcohol consumption, night shifts, use of certain medications, anxiety, depression, sleep apnea, or other sleep disorders may be factors.
Researchers were surprised to find no age-related differences in the association between sleep duration and hypertension, given that sleep patterns tend to change with age. Participants’ ages ranged from 35.4 to 60.9 years, and over half (61%) were women. Compared to men, women who slept less than seven hours had a 7% higher risk of developing high blood pressure.
"Sleeping too little seems to be riskier for women," said Hosseini. "The difference is statistically significant, though we´re not sure it’s clinically significant, and it should be studied further. What we do see is that poor sleep patterns can increase the risk of high blood pressure, which we know can pave the way for heart disease and strokes."
It’s important for individuals to discuss their sleep patterns with their healthcare team, especially if they’ve experienced sleep disturbances that might be due to obstructive sleep apnea. Sleep apnea has been linked to higher rates of high blood pressure, stroke, and coronary artery disease.
This study has several limitations, including the fact that sleep duration was based on self-reported questionnaires, so changes in sleep duration during the follow-up period weren’t evaluated. Additionally, there were variations in how short sleep duration was defined across studies (less than five or six hours).
"More research is needed to assess the association between sleep duration and high blood pressure using more precise methods like polysomnography, a way to evaluate sleep quality more accurately," Hosseini said. "Furthermore, the variations in reference sleep duration highlight the need for a standardized definition in sleep research to improve comparability and generalization of findings across different studies."
Aayushi Sood, MD, lead author and medical resident at the Wright Center for Graduate Medical Education, will present the study “Sleep Duration and Incidence of Hypertension: A Systematic Review and Meta-Analysis” on Sunday, April 7 2024 at 9:15 a.m. – 1:15 p.m. UTC in Pavilion B4-5.
