Cardiovascular health and Sleep

Obstructive sleep apnea is commonly associated with obesity, which is a risk factor for hypertension and coronary artery disease (CAD); however, recent research has implicated OSA as an independent risk factor for cardiovascular disorders.

excerpt from GlobalRPH.com

Sleep and Heart Disease: What's the Link?

Summary & Participants

Everyone knows that a good night's sleep makes you feel better the next day. But did you know that how long you sleep might be a factor in heart disease? Learn how sleep might be linked to the health of your heart.

Authors:
Sanjay Patel, MD
Instructor in Medicine, Harvard Medical School
David White, MD
Associate Professor of Medicine, Harvard Medical School

Editorial Consultant:
Daniel Buysse, M.D.
University of Pittsburgh School of Medicine

Medically Reviewed On: Tuesday, January 20, 2004

Webcast Transcript

ANNOUNCER: We know that factors like smoking, obesity, diabetes and high blood pressure can increase our risk of heart disease. But there's another element that might come as surprise.

DAVID P. WHITE, MD: There's some early evolving evidence that how much you sleep may contribute to development of coronary artery disease, or heart attacks

ANNOUNCER: In fact, a recent study tracked the health of over 70,000 women. Researchers came up with some surprising results.

DAVID P. WHITE, MD: We followed them for about ten years, and what we found was that if you sleep less than six or seven hours per night, the incidence of heart attacks went up relatively steeply. People that slept approximately five hours a night had about a 40% higher rate of having a heart attack than did people that slept eight hours. With a similar group, if you looked at the nine and over hour group, they tended to have something, not quite as big an effect in that group, but a substantial effect as well.

ANNOUNCER: But why should how long we sleep be linked to heart problems? We can look for clues in the way sleep affects some basic body functions.

SANJAY PATEL, MD: Blood pressure tends to be lower when we sleep, so if we're sleeping less, than our blood pressure over the course of a day tends to be higher.

DAVID P. WHITE, MD: Elevated blood pressure just makes the heart work harder, and in every scenario that is a negative. Studies that have people sleep-deprived for a fairly short period of time, they can show that sympathetic nervous system becomes substantially activated, meaning that the output to your blood vessels, things like that, all become activated, which causes those vessels to squeeze down and whatnot.

ANNOUNCER: Another explanation may come from tipping the balance of the stress hormone cortisol.

SANJAY PATEL, MD: People who aren't sleeping enough, who are sleep deprived, tend to have higher levels of cortisol, and so again, this puts a stress on the heart.

ANNOUNCER: And sleeping too long may also increase your risk of heart disease, but the reasons for that are less clear.

SANJAY PATEL, MD: People who sleep too long tend to weigh more than people who sleep less. They tend to smoke more. They tend to drink more alcohol. They tend to exercise less. And so all of these are possible reasons for why people who sleep nine or ten hours a night have more heart disease, but we're just not sure.

ANNOUNCER: Still researchers can't be sure if poor sleep is the cause of heart problems or just an early sign of the disease. Yet the length of sleep may just be part of the equation. Experts have identified another potential problem: sleep apnea.

DAVID P. WHITE, MD: Sleep apnea is a condition that's characterized by a collapse of the airway when you go to sleep, meaning the airway behind the tongue, the uvula (that thing that hangs in the back of your throat), and the soft palette basically collapses in these individuals when they go to sleep, such that they can't breathe. And so, they go to sleep, the airway collapse; they transiently arouse, open up the airway, take three or four breaths, and go back to sleep and do it again.

ANNOUNCER: This kind of sleep disturbance strains the body and the heart

DAVID P. WHITE, MD: There's substantial literature suggesting that the recurrent hypoxia (falls in oxygen) that occur and the elevations in carbon dioxide, contribute to the development of heart disease. It clearly contributes to the development of high blood pressure, and at least cross-sectionally, it leads to the development of heart attacks, strokes, and congestive heart failure, as well.

ANNOUNCER: For people who already have a heart condition, good sleep is yet another important factor in trying to avoid another occurrence of heart problems.

SANJAY PATEL, MD: It would seem from all the studies that are know that getting a good night's sleep is just as important as many of the other things that doctors now recommend for people who have heart disease to prevent a second heart attack or worsening of their heart disease.

ANNOUNCER: While research into the link between sleep and heart disease has many unanswered questions, what's clear is that sleep is an element in keeping both body and mind alert and healthy.

DAVID P. WHITE, MD: There's evolving evidence that getting a reasonable quantity of good quality sleep is important in maintaining health and particularly heart health.