“Sleep is something you can do on an individual level to potentially protect or improve your heart health,” says Dr. Marwah Abdalla, a cardiologist at NewYork-Presbyterian/Columbia University Irving Medical Center. “Growing evidence shows that not getting enough sleep, or poor sleep quality, can lead to problems like high blood pressure or heart disease.”
Unfortunately, many people are not getting enough sleep: Almost half of all Americans say they feel sleepy during the day between three and seven days a week, according to the National Sleep Foundation (NSF), which recommends between seven and nine hours of sleep a night for healthy adults and between nine and 13 hours for children, depending on their age. More than 35% of adults in the United States report sleeping less than seven hours a night.
“We live on the edge in terms of sleep,” says Dr. Ana Krieger, director of the Center for Sleep Medicine at NewYork-Presbyterian/Weill Cornell Medical Center and Weill Cornell Medicine. “We need to make sleep a priority.”
How can you prioritize sleep and, in turn, help your heart? Health Matters spoke to Dr. Krieger and Dr. Abdalla to learn more about the link between sleep and heart health and ways to improve your sleep.
Sleep Apnea’s Impact on the Heart
One of the biggest threats to sleep and heart health is a common sleep disorder, obstructive sleep apnea (OSA), which occurs when the muscles in the back of your throat relax too much and narrow your airways, causing you to repeatedly stop and start breathing while you sleep. OSA is estimated to affect 2% to 9% of adults in the United States, though many cases go undiagnosed, according to the NSF.
The frequent drops in oxygen “can lead to all sorts of stress on the body, including damaging the vessels that supply blood to the heart, and can cause direct injury to the heart itself,” says Dr. Abdalla, who is also the Florence Irving Associate Professor of Medicine at Columbia University Vagelos College of Physicians and Surgeons. “OSA can also lead to a type of high blood pressure that affects the arteries in the lungs and right side of the heart, called pulmonary hypertension, and can cause heart failure.”
A lack of oxygen affects every organ, including the mechanics of the heart. “The heart and lungs share space in the chest wall, so as the lungs labor to breathe, the heart is also subjected to that physical stress, which can thicken the heart muscles and affect the function of the heart,” says Dr. Krieger, who is also chief of the Division of Sleep Neurology and a professor of clinical medicine in the departments of medicine, neurology and genetic medicine at Weill Cornell Medicine.
Shallow and forceful breaths wake up the brain to restore breathing, disrupting the sleep cycle and adding stress to the body. “By waking up, the brain now releases adrenaline and stress hormones to restore respiratory function, open up the airway muscles, and get you to breathe normally,” says Dr. Krieger. “This stresses the heart, increasing your heart rate and blood pressure.”
Sleep apnea increases the risk of developing blood clots, according to research led by Dr. Krieger. “We found that people, even with mild degrees of sleep apnea, have platelets that tend to stick to each other, which can lead to clotting,” she says. “This can be a contributing factor to cardiovascular disease in patients with sleep apnea.”
“Preparing for a good night’s sleep starts long before you tuck yourself under the covers. That means getting light exposure throughout the day, limiting caffeine intake, and managing stress.”
Symptoms of sleep apnea include excessive tiredness during the day; loud snoring, punctuated by gasping or choking sounds; persistent headaches in the morning; dry mouth upon waking; and restless sleep, according to the NSF. The risk of developing OSA increases with age until a person is in their 60s and 70s, and men or people assigned male at birth are generally more likely to develop OSA. Head and neck anatomy, as well as body weight, can also be a risk factor.
Sleep apnea diagnosis involves sleep monitoring, either at a sleep center or at home, and treatments include oral guards to bring the jaw forward to open up the airway space, or a CPAP (continuous positive airway pressure) machine, a mask that helps restore airflow while you sleep, which is typically recommended for the more severe cases of sleep apnea.
Sleep Quantity Matters
How much you sleep matters — even though it’s often the first thing to be sacrificed amidst a hectic schedule. “When you don’t sleep enough, you feel on edge,” says Dr. Abdalla. “Short sleep duration can disrupt the body’s systems, causing hormonal imbalances, which in turn impact the blood vessels.”
Dr. Abdalla is leading research to better understand this connection. In a large study published in the International Journal of Cardiology Hypertension, Dr. Abdalla and her colleagues assessed the sleep habits and blood pressure of nearly 900 working adults. The study found that shorter sleep duration is associated with higher blood pressure in a 24-hour period and potential cardiovascular risk.
Dr. Abdalla is also studying how different stages of sleep influence the heart. “Sleep is a complex behavior,” she says. “If you fall into a deep sleep, it can be a restorative space where we consolidate memories and bring our bodies to a healthier state. It’s a big mystery as we try to figure out how the different parts of sleep interact with each other.”
Tips to Prioritize Sleep
While there is no simple button to press to make sure you get enough good, quality sleep each night, there are steps you can take to understand and respect your body’s rhythm.
Dr. Abdalla and Dr. Krieger agree that preparing for a good night’s sleep starts long before you tuck yourself under the covers. That means getting light exposure throughout the day, limiting caffeine intake, and managing stress.
“Getting sunlight throughout the day reminds your body that it is daytime, which helps build up the sleep drive and cues a rise in the sleep hormone, melatonin,” says Dr. Abdalla. She also suggests avoiding caffeine after 12 noon, if possible, because caffeine has a long half-life and remains in your system long after you finish an afternoon cup of coffee.
They also encourage creating a dark, cold environment for sleep, and avoiding stimuli late at night, like exercise or too much time on your phone or other device. “One of the most offensive things to sleep is our phones,” says Dr. Abdalla, who advises people to keep phones out of the bedroom and not use them as your alarm.
Stress and worry are other culprits that keep people awake at night, say Dr. Abdalla and Dr. Krieger, who both suggest keeping a worry log to get thoughts out. Meditation, yoga, and breathing exercises are other positive ways to relax and help mitigate worry.
“If you don’t process your worries throughout the day, when you lie down to sleep, they may trigger a state of anxiety,” says Dr. Krieger. “Often, I recommend that people take 10 to 15 minutes of worry time during the day, where they can sit down to think about the stressful items in their lives, and start a simple worry list with actionable items. When this is done, the effect is often quite noticeable as people start to embrace the challenges in their lives and no longer feel that acute stress and racing thoughts that used to interfere with sleep.”
Dr. Marwah Abdalla is a clinical cardiologist and cardiac intensivist at NewYork-Presbyterian/Columbia University Irving Medical Center, and the Florence Irving Associate Professor of Medicine at Columbia University Vagelos College of Physicians and Surgeons.
She is the director of education for the cardiac intensive care unit. Her areas of expertise include critical care cardiology and hypertension. She is also an NIH-funded clinical investigator with a research expertise in the cardiovascular manifestations of hypertension, assessed by echocardiography, ambulatory blood pressure monitoring, and sleep.
Dr. Ana C. Krieger is the director of the Center for Sleep Medicine at NewYork-Presbyterian/Weill Cornell Medical Center and Weill Cornell Medicine, and professor of clinical medicine, professor of medicine in clinical neurology, and professor of clinical genetic medicine at Weill Cornell Medicine. A clinician-scientist, she investigates mechanisms of cardiovascular disease in sleep disorders. She actively collaborates with many investigators in the field of sleep medicine and has contributed to multiple scientific publications and presentations.