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Experts say adequate sleep is important for health, especially for women. Tommaso Tuzj/Stocksy
  • Researchers are reporting that the fewer hours a person sleeps, the higher their risk of high blood pressure.
  • Evidence linking less sleep to hypertension isn’t new, but conclusions have been inconsistent in the past.
  • The risk of high blood pressure is greater in women who sleep less.

Sleeping fewer than 7 hours a night is associated with a higher risk of high blood pressure over time, according to a new study.

The findings, which haven’t been published yet in a peer-reviewed journal, are being presented at the American College of Cardiology’s Annual Scientific Session.

The study authors acknowledged the association between sleep patterns and high blood pressure, also known as hypertension, isn’t necessarily a revelation.

However, they said evidence of the connection has been inconsistent in the past.

The researchers looked at data from 16 studies done between January 2000 and May 2023.

The information involved incidences of hypertension in 1,044,035 people in six countries who didn’t have a history of high blood pressure over follow-up periods ranging from 2 to 18 years (with a median of 5 years).

The researchers reported that those sleeping for shorter periods had a significantly higher risk of developing hypertension, even after adjusting for demographic and cardiovascular risk factors that included smoking, blood pressure, body mass, education, gender, and age.

The association was even stronger for people getting fewer than five hours of sleep.

“Based on the most updated data, the less you sleep — that is less than seven hours a day — the more likely you will develop high blood pressure in the future,” said Dr. Kaveh Hosseini, the study’s principal investigator and an assistant professor of cardiology at the Tehran Heart Center in Iran, in a statement. “We saw a trend between longer sleep durations and a greater occurrence of high blood pressure, but it was not statistically significant. Getting seven to eight hours of sleep, as is recommended by sleep experts, may be the best for your heart, too.”

The research team reported that sleeping fewer than 7 hours was associated with a 7% increased risk of developing high blood pressure. That number increased to 11% when sleep duration was less than 5 hours.

Hosseini said the team compared that to the effects of diabetes and smoking, which they said are known to increase a person’s risk of hypertension by at least 20%.

Hosseini said that while researchers didn’t specifically look at possible causes, disrupted sleep could be to blame.

He said other factors could include sleep disorders such as sleep apnea as well as depression, anxiety, use of certain medications, alcohol, nightshift work, overeating, or other lifestyle habits.

The study participants’ ages ranged from 35 years to 61 years. More than half (61%) were female.

Females reporting fewer than 7 hours of sleep had a 7% greater risk of developing high blood pressure.

The researchers expressed surprise they didn’t find age-based differences in the association between sleep duration and hypertension, as sleep patterns frequently shift as people age.

“Getting too little sleep appears to be riskier in females,” Hosseini said. “The difference is statistically significant, though we are not sure it’s clinically significant and should be further studied. What we do see is that lack of good sleep patterns may increase the risk of high blood pressure, which we know can set the stage for heart disease and stroke.”

The team said the study has limitations, including the data being self-reported so changes in sleep duration over the follow-up period weren’t assessed. There were also variations in the definitions of short sleep duration between the studies (fewer than 5 or 6 hours).

“Further research is required to evaluate the association between sleep duration and high blood pressure using more accurate methods such as polysomnography, a method for evaluating sleep quality more precisely,” Hosseini said. “Moreover, the variations in reference sleep duration underline the need for standardized definition in sleep research to enhance the comparability and generalizability of findings across diverse studies.”

Dr. Cheng-Han Chen, an interventional cardiologist and medical director of the Structural Heart Program at MemorialCare Saddleback Medical Center in California, told Medical News Today more research needs to be done to determine why women have a higher risk.

“As poor sleep is thought to increase stress hormones that can increase blood pressure, it is possible that women have a heightened stress response to sleep disruption,” said Chen, who wasn’t involved in the study.

Susan Miller is a certified sleep expert and lead researcher at SleepMattressHQ.com, a site dedicated to helping people attain better sleep.

Miller, who wasn’t involved in the study, told Medical News Today that the higher risk in women could be attributed to hormonal factors, “particularly fluctuations in estrogen levels, which may influence sleep patterns and cardiovascular health differently.”

“Women are more likely to experience sleep disturbances related to hormonal changes during menstruation, pregnancy, and menopause,” she said. “Social and environmental factors also add to the factors like caregiving responsibilities and work-related stress that affect women’s sleep quality and quantity. all these contribute to increased hypertension risk.”

Chen added that the importance of sleep on overall health is becoming clearer as more research looks at the effects of low-quality sleep.

“However, there is still much that we do not understand regarding the mechanisms by which poor sleep impacts health outcomes,” he said. “Some healthy sleep habits are keeping the bedroom cool, dark, and quiet, avoiding caffeine and alcohol, going to sleep around the same time each day, getting regular exercise during the day, and avoiding naps in the afternoon.”

Dr. Rigved Tadwalkar, a consultant cardiologist at Providence Saint John’s Health Center in California, told Medical News Today that adequate sleep allows the body to rest and repair itself.

“(It also) is regulating hormones that influence blood pressure, inflammation, and blood sugar levels, all of which are critically important for heart health,” said Tadwalkar, who wasn’t involved in the study.

He suggested a number of ways for people to improve their sleep.

“Maintain a consistent sleep schedule,” Tadwalkar advised. “To guarantee a more restful night, adhere to a steady sleep routine. Consistency is key. Going to bed and waking up at the same times daily, including on the weekends, contributes to regulating your internal clock, resulting in enhanced sleep quality.”

“If necessary, resist the temptation to oversleep by more than an hour beyond your regular waking time, as this practice supports the stability of your sleep patterns,” he added.

Tadwalkar said it’s important to create a relaxing bedtime routine.

“Rethink your pre-sleep activities. Steer clear of stimulating pursuits like screen time before bedtime,” he recommended. “Instead, embrace calming rituals such as reading a book or practicing relaxation techniques to signal to your body that it’s time to wind down.”

Tadwalkar said optimizing your sleep environment also helps.

“Keep the room cool, dark, and quiet to enhance the sleep environment,” he advised “Get rid of noise and light sources to the greatest extent possible and tweak the temperature to create an ideal setting for a peaceful night’s sleep.”

And if difficulties persist, Tadwalkar said it’s important to consult with a healthcare professional for further evaluation and personalized advice.

“They can assist in identifying any underlying causes of sleep problems and recommend the most appropriate treatment options. Particularly, consider seeking help from a sleep medicine doctor, who specializes in the diagnosis and treatment of sleep disorders,” Tadwalkar said. “Sleep medicine doctors have the expertise to conduct specialized tests, develop tailored treatment plans, and provide guidance for long-term sleep health.”