Middle-aged women who sleep less than five hours a night are up to 75 percent more likely to develop heart failure or stroke, a new study shows.
Scientists at the University of Pittsburgh followed nearly 3,000 women aged 42 to 52 over the course of 16 years.
Every year for almost two decades, the women completed surveys about their sleep, including how many hours they slept per night on average and whether they thought they suffered from insomnia.
They also completed health questionnaires to track ongoing illnesses or problems.
The data analysis found that women who regularly got less than five hours of sleep per night were up to 75 percent more likely to develop a number of cardiovascular problems, including stroke, heart attack, heart failure and coronary artery disease.
Strikingly, this association remained true even when other potentially contributing factors, such as BMI and underlying health conditions, were taken into account.
The scientists said this may be because too little sleep can increase blood pressure and cause insulin resistance, increasing the risk of damage to blood vessels.
They also warned that the risk of obesity – which is known to affect heart health – increases due to the deregulation of the body’s hunger and fullness hormones.
The above graph indicates that sleeping less than five hours per night increases the risk of heart disease in middle-aged women
Data showed that women who slept less than five hours a night were up to 75 percent more likely to have heart problems.
The Center for Disease Control and Prevention (CDC) recommends that all Americans get seven to nine hours of sleep every night.
But studies show that as many as one in three adults regularly fail to achieve this goal.
Research shows that about half of middle-aged women fail to get the recommended seven hours of sleep per night.
Women in this age group are already at increased risk of heart disease. The drop in estrogen levels after menopause can cause this cause blood vessels to stiffen, interrupting blood flow to the heart.
The study, published in the Journal of the American Heart Association Circulationusd data from the Study of Women’s Health Across the Nation (SWAN) – which followed thousands of women for 22 years.
It recruited pre-menopausal women between 42 and 52 years old in 1996 and then followed them for the next 16 years.
During the study period, 200 cardiovascular events were reported, of which 23 resulted in a fatal outcome.
Cardiovascular events were defined as myocardial infarction – or heart attack – heart attacks or treatment for coronary artery disease.
About 10 percent reported having trouble falling asleep every night, while a quarter said they woke up several times during the night.
In total, 363 people (14 percent) reported sleeping less than five hours per night on average, while 760 people (30 percent) said they slept more than eight hours per night.
The majority of women – 1,395 or 55 percent – reported sleeping an average of about six hours and thirty minutes per night.
The researchers conducted an analysis that took into account factors such as 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 develop heart disease than those who slept six and a half hours each night.
They also conducted a second analysis, which also looked at reports of insomnia symptoms such as difficulty falling asleep, waking up several times a night or waking up earlier than planned.
It found that those who slept less than five hours a night on average and had insomnia symptoms more than three times a week were 75 percent more likely to have heart disease.
They were compared to women who slept the recommended amount and said they rarely experienced insomnia symptoms.
The study authors, led by cardiologist Dr. Rebecca Thurston, wrote: ‘Insomnia symptoms, when they persist into middle age or occur with short sleep, are associated with a higher risk of cardiovascular disease in women.’
Limitations of the study included that sleep duration and insomnia symptoms were self-reported and not monitored by a medical device such as a smartwatch.
The researchers also didn’t take into account other factors that affect sleep, such as timing, regularity and efficiency – or the amount of light, deep and REM sleep a person had.
Cardiovascular disease is the leading cause of death among women in the US, with approximately 300,000 deaths annually.
More than 60 million women in the US also live with some form of heart disease.