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How a sleep shortfall can stress your heart

Getting less than six hours of sleep on a regular basis can boost levels of stress hormones, which can strain your cardiovascular system.

Find out if your sleeping habits put you at risk—and what to do about it.

If you wake up most mornings feeling groggy and grumpy instead of refreshed and alert, you may be among the 70 million Americans who suffer from chronic sleep problems. Trouble falling or staying asleep (insomnia) is the most common complaint. But sleep apnea—a condition marked by loud snoring punctuated by frequent breathing lapses—could also be to blame. Whatever the cause, a chronic sleep shortfall strains your cardiovascular system, potentially raising your risk of a heart attack or a stroke.

“Emerging evidence from both clinical and population-based studies shows that insufficient sleep or sleep disturbances contribute to cardiac stress,” says Dr. Susan Redline, the Peter C. Farrell Professor of Sleep Medicine at Harvard Medical School. Not enough sleep means sleeping less than six hours a night—something that one in five people reports. Sleep-deprived people have higher blood levels of stress hormones and substances that indicate inflammation, a key player in cardiovascular disease. Even a single night of insufficient sleep can perturb your system, says Dr. Redline.

Unable to snooze?

Most people have trouble sleeping once in a while, but frequent episodes can morph into an unhealthy pattern. Sometimes, deeply ingrained habits like staying up too late or engaging in stimulating activities before bed are to blame. But nearly half of insomnia cases stem from psychological or emotional issues, such as stressful events, mild depression, or an anxiety disorder.

Following basic sleep hygiene strategies may help. Go to bed and wake up at the same times each day. Keep your bedroom cool, dark, and comfortable. Use your bed for sleep and sex only. If you can’t fall asleep within 15 minutes, get up and leave the bedroom. Read or do another quiet activity for 15 to 20 minutes until you get sleepy.

If you need extra help, consider cognitive behavioral therapy for insomnia. This therapy helps you change your sleep behaviors, thoughts, and habits. You can buy online programs to learn this nondrug technique, which has been shown to improve sleep in a number of studies. More information is available at the Conquering Insomnia Program (www.cbtforinsomnia.com) and Sleep Healthy Using the Internet (www.shuti.me).

Disrupted sleep

For some people, sleep apnea is to blame for a sleep shortfall. In the most common form, obstructive sleep apnea (OSA), the tongue or throat tissue blocks the airway. This causes the person to temporarily stop breathing many times a night. The resulting drop in oxygen triggers the brain to send an emergency “breathe now” signal that briefly wakens the sleeper, who then gasps for air.

The low oxygen and high carbon dioxide levels that occur during these bouts of breathlessness exacerbate the physiological changes caused by the frequent awakenings, explains Dr. Redline. Rising stress hormones boost blood pressure and heart rate. Inflammation damages the delicate inner lining of the blood vessels and makes the blood more likely to clot. People with moderate to severe OSA have three times the risk of a stroke compared with people who don’t have the condition. OSA also appears to raise the risk of heart attack, heart rhythm disorders, and heart failure.

Test yourself for sleep apnea with STOPBANG

A “yes” answer to three or more of these questions suggests possible sleep apnea. Ask your doctor if you should have a home sleep study.

 — Snore: Have you been told that you snore?

T — Tired: Do you often feel tired during the day?

O — Obstruction: Do you know if you briefly stop breathing while asleep, or has anyone witnessed you do this?

— Pressure: Do you have high blood pressure or take medication for high blood pressure?

B — Body mass index (BMI): Is your BMI 30 or above? (For a calculator, see www.health.harvard.edu/bmi.)

A — Age: Are you 50 or older?

N — Neck: Is your neck circumference more than 16 inches (women) or 17 inches (men)?

G — Gender: Are you male?

A CPAP machine treats apnea by preventing the collapse of the airway during sleep.

How CPAP helps

If you suspect you have OSA, take the STOPBANG quiz (see box). The most effective treatment is wearing a facemask tethered to a bedside air pump, a system called continuous positive airway pressure (CPAP) therapy. Using a CPAP device every night can be a challenging adjustment, but better-fitting, smaller masks have made the therapy easier to use than in the past. And the effort pays off, says Dr. Redline. “We know that CPAP reduces daytime sleepiness and improves quality of life, and may lower blood pressure,” she says. Other research suggests the therapy may lower rates of cardiovascular disease and related deaths, although that hasn’t been proved in a controlled trial.

“Sleep apnea is quite common in people at risk for heart disease,” says Dr. Redline. If you’re worried you might have apnea, ask your doctor about a home overnight sleep study, which can confirm the problem. For more information, see MyApnea.Org (www.myapnea.org), a national network developed by Dr. Redline and colleagues to help people learn about the disorder, connect with fellow patients, and contribute to new research aimed at improving sleep apnea diagnosis and treatment. 

Images: Thinkstock

Posted by: Dr.Health

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