Middle-aged women who sleep less than five hours every night are up to 75 percent more likely to suffer heart failure or stroke, a new study suggests.
Scientists at the University of Pittsburgh tracked nearly 3,000 women aged 42 to 52 over the course of 16 years.
Each year for almost two decades, the women completed surveys about their sleep — including how many hours they slept on average each night and if they considered themselves to suffer insomnia.
They also filled in health questionnaires to keep record of ongoing diseases or problems.
The data analysis revealed that women who regularly slept for fewer than five hours sleep per night were up to 75 percent more likely to suffer a number of cardiovascular problems — including stroke, heart attack, heart failure and coronary artery disease.
Strikingly, this relationship remained true even when other, potentially contributing factors were accounted for, such as BMI and underlying health conditions.
The scientists said this may be because too little sleep can raise blood pressure and trigger insulin resistance, raising the risk of damage to blood vessels.
They also warned it raised the risk of obesity — known to impact heart health — due to deregulation of the body’s hunger and fullness hormones.
The above graph indicates that sleeping less than five hours per night raises the risk of heart disease in middle-aged women
Data revealed women who slept fewer than five hours a night were up to 75 percent more likely to suffer heart problems.
The Center for Disease Control and Prevention (CDC) recommends that all Americans get seven to nine hours of sleep every night.
But surveys suggest as many as one in three adults are regularly failing to hit this target.
Among women who are middle-aged, surveys suggest about half fail to get the recommended seven hours of sleep every night.
Women of this age group are already at an increased risk of heart disease. The drop in estrogen levels following the menopause can cause blood vessels to become stiffer, interrupting blood flow to the heart.
The study, published in the American Heart Association’s journal Circulation, usd data from the Study of Women’s Health Across the Nation (SWAN) — which tracked thousands of women over 22 years.
It recruited pre-menopausal women aged 42 to 52 years old in 1996 and then tracked them over the next 16 years.
Over the study period, there were 200 cardiovascular events reported — of which 23 resulted in a fatality.
Cardiovascular events were defined as mycardial infarction — or heart attack — heart attacks or receiving treatment for coronary artery disease.
About 10 percent reported trouble falling asleep every night while a quarter said they were waking up several times during the night.
A total of 363 — or 14 percent — reported sleeping less than five hours every night on average while 760 — or 30 percent — said they slept more than eight hours per night.
The majority of the women — 1,395 or 55 percent — reported sleeping about six hours and 30 minutes every night on average.
The researchers carried out an analysis adjusting for factors including age, BMI, ethnicity, education and underlying conditions.
They found that women who slept less than five hours per night on average were 72 percent more likely to suffer from heart disease than those who slept six-and-a-half hours every evening.
They also carried out a second analysis that also looked at reports of insomnia symptoms such as trouble falling asleep, waking up several times a night or waking up earlier than planned.
It revealed that those who slept for less than five hours per night on average and had insomnia symptoms more than three times per week were 75 percent more likely to suffer from heart disease.
They were compared to women who slept the recommended amount and said they only rarely suffered from insomnia symptoms.
The study authors, led by Pittsburgh Foundation Chair in Women’s Health and Dementia Dr Rebecca Thurston, wrote: ‘Insomnia symptoms, when persistent over midlife or occuring with short sleep, are associated with higher cardiovascular disease risk among women.’
Limitations of the study included that sleep duration and insomnia symptoms were self-reported, and were not monitored by a medical device such as a smartwatch.
The researchers also did not consider other factors affecting sleep including timing, regularity and efficiency — or the amount of light, deep and REM sleep someone had.
Cardiovascular disease is the number one killer of women in the US, with about 300,000 dying from this every year.
Over 60million women in the US are also living with some form of heart disease.