There's a "sweet spot" for the amount of sleep you should get to reduce your risk of heart attack and stroke, new research shows.
Folks who get six to seven hours of sleep a night -- no more, no less -- have the lowest chance of dying from a heart attack or stroke, according to new findings.
Waking early or dozing on past that ideal window increases your risk of heart-related death by about 45%, researchers found.
This trend remained true even after they accounted for other known risk factors for heart disease or stroke, including age, high blood pressure, diabetes, smoking, BMI (body mass index), and high cholesterol levels.
"Even then, sleep came out to be an independent risk factor," said lead researcher Dr. Kartik Gupta, a resident in internal medicine at Henry Ford Hospital in Detroit.
For the study, Gupta and his colleagues analyzed data from more than 14,000 participants in the federally funded U.S. National Health and Nutrition Examination Survey between 2005 and 2010. As part of the survey, these folks were asked how long they usually slept.
Researchers tracked participants for an average of 7.5 years to see if they died from a heart attack, heart failure or stroke. They also assessed their heart health risk scores as well as their blood levels of C-reactive protein (CRP), which increases when there's inflammation in your body. High CRP levels have been associated with heart disease.
The research team found a U-shaped relationship between heart risk and sleep duration, with risk at its lowest among people who got between six and seven hours of sleep on average.
A lack of sleep already has been linked to poor heart health, said Dr. Martha Gulati, editor-in-chief of CardioSmart.org, the American College of Cardiology's educational site for patients.
"We have a lot of data related to less sleep," said Gulati, a cardiologist. She noted that a number of key heart risk factors -- blood pressure, glucose tolerance, diabetes, and inflammation -- are exacerbated by too little sleep.
There's not as much evidence regarding those who slumber too long and their heart risk, however, Gulati and Gupta said.
Gupta and his colleagues found one possible explanation in their research. Based on patients' levels of CRP, inflammation accounted for about 14% of heart-related deaths among short sleepers and 13% among long sleepers, versus just 11% of folks who got the optimal six to seven hours of sleep.
"Patients who sleep for six to seven hours have the least CRP, so this inflammation might be driving increased cardiovascular risk," Gupta said.
It might be that people who sleep longer than seven hours are just getting lousy sleep, and so have to doze longer, Gulati said. Poor quality sleep could be driving the increased risk among late snoozers.
"You wonder if somebody is sleeping longer because they just didn't get a good night's sleep," Gulati said. "I always say there's good sleep and there's bad sleep. You might be in bed for eight hours, but is it good quality sleep?"Here are some tips for improving your sleep, courtesy of Harvard Medical School:
- Avoid caffeine and nicotine four to six hours from bedtime.
- Keep your bedroom dark, quiet and cool to promote better sleep.
- Establish a relaxing routine an hour or so before bed.
- Don't try to force yourself to sleep -- if you aren't asleep within about 20 minutes, get up and do something relaxing for a bit until you feel sleepy.
- Eat dinner several hours before bedtime and avoid foods that can upset your stomach.
- Exercise earlier in the day, at least three hours before bed.
"In the medical community we know it's important to sleep, but we still don't treat it like something we should be asking about routinely," Gulati said. "I wish I could say doctors were good enough at asking about sleep. I think it should be like a vital sign."
The findings were presented virtually on May 15 at the annual meeting of the American College of Cardiology. Findings presented at medical meetings are considered preliminary until published in a peer-reviewed journal.
What can be done about sleep apnea?
Treatments like continuous positive airway pressure (CPAP) therapy have been extremely successful in treating sleep apnea and many of its related symptoms and comorbidities. Treating underlying conditions of heart disease, such as sleep apnea, can greatly reduce the chances of developing more serious health problems.
When patients that were both at risk for heart disease and had sleep apnea were treated with CPAP machines, the patient's nighttime and daytime blood pressure was significantly reduced.
To fully assess the risk of sleep apnea and heart disease, a sleep study should be performed by a sleep specialist to both diagnose the disorder and rule out any other sleep disorders or identify any sleep-related comorbidities.
Most insurance plans cover sleep studies as part of their policies. While sleep studies can be somewhat costly, they pale in comparison to the medical costs of treating heart disease.
If you believe you may have sleep apnea and are concerned about the health risks associated with the disorder, discuss your symptoms with your primary physician and ask if a sleep study is right for you. And if you live in Alaska be sure to ask them about having your study performed at The Alaska Sleep Clinic, or contact us for a free 10-minute phone consultation by clicking the link below.