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Late nights, early mornings a 'ticking time bomb' for health
February 9th, 2011
01:45 PM ET

Late nights, early mornings a 'ticking time bomb' for health

We all know that getting enough shut-eye is good for us, but now a new study suggests that getting too little sleep can increase the risk of heart attack, stroke and other cardiovascular disease that can result in early death.

Researchers found if you sleep less than six hours, or have disturbed sleep you have a 48% chance of developing or dying from heart disease, and a 15% chance of having or dying of a stroke.  The study, published in the European Heart Journal, is a meta-analysis of 15 other sleep studies.  A meta-anaylsis integrates a number of studies into one study. Researchers followed nearly 475,000 adults from eight countries including the United States, United Kingdom, Japan, and Israel for seven to 25 years.

"There is an expectation in today's society to fit more into our lives. The whole work/life balance struggle is causing too many of us to trade in precious sleeping time to ensure we complete all the jobs we believe are expected of us," said Professor Francesco Cappuccio of the University of Warwick Medical School in the United Kingdom and a lead author of the study. "The trend for late nights and early mornings is actually a ticking time bomb for our health so you need to act now to reduce your risk of developing these life-threatening conditions."

Cappuccio says  getting between six and eight hours of sleep regularly is optimum. "By ensuring you have about seven hours of sleep a night, you are protecting your future health and reducing the risk of developing chronic diseases. If you reduce your sleep below a certain level–five hours or less–you run into trouble,"  he said. "Not just tomorrow because you are tired, but you build up a steady risk of developing a chronic condition late in life. Sleep is not a commodity that can be traded off."

Dr. Michelle Miller, also from the University of Warwick and co-author of the study, says sleep deprivation actually causes a number of changes in the body.  "Chronic short sleep produces hormones and chemicals in the body which increase the risk of developing heart disease and strokes, and other conditions like high blood pressure, cholesterol, diabetes and obesity."  All of those conditions are also risk factors for heart attack and stroke.  Hormone changes can lead to glucose intolerance and insulin resistance–both markers that lead to type 2 diabetes and increases in blood pressure. Chronic lack of sleep can activate a chemical in the body called cytokines, inflammation markers that are the basis for atherosclerosis–or hardening of the arteries–also common in people who have heart attacks and stroke.

But getting too much sleep can also have negative implications. Cappuccio says sleeping more than nine  hours could be an indication of illness–including cardiovascular disease. "Long sleep rather than being the cause of disease is more likely to represent an early marker, the early stages of chronic conditions like depression."

He says sleep deprivation has to be considered a lifestyle risk factor similar to smoking, alcohol and lack of exercise.

According to American Heart Association spokesman Dr. Ralph Sacco, sleep is under recognized as a potential cardiovascular risk factor, and while this study provides intriguing evidence of the relationship, there is still a lot that is unknown about sleep disorders and their connection to heart disease and stroke.

"This is an association study that adds to evidence about an association but cannot determine mechanism or causation," said Sacco. "We can't make any causal claims yet based on this study that demonstrates an association but it raises suspicion about sleep disorder and cardiovascular and stroke risk."

Sacco says right now, there is a lot more evidence that the AHA's key health factors called "life's simple 7" improve heart health and reduce the risk of heart attack and stroke. They are:
1. Get active
2. Eat better
3. Lose weight
4. Stop smoking
5. Control cholesterol
6. Manage blood pressure
7. Reduce blood sugar


soundoff (121 Responses)
  1. SoundGuy

    A good tip for those with trouble falling asleep: play sounds of nature in the background and concentrate on the nuances and subtleties of all the randomness of such natural sounds. Try some free mp3s from a site called transcendentaltones. Works wonders with kids!

    February 10, 2011 at 03:32 | Report abuse | Reply
  2. Matt

    They forgot to mention the crackberry link The bliking crackberry at 4:20am beckons you like the "call of the sirens" causing you to read an article about lack of sleep leading to heart disease causing you to not sleep more causing you to read your crackberry more causing you to respond to emails and more ridiculous articles causing a viscious circle that in the end, gives you carpel tunnel syndrome, sore thumbs, bad eyesight, baggy eyes, irritability, heart disease and eventually death. Wth? Somebody kill me..

    February 10, 2011 at 04:43 | Report abuse | Reply
  3. SleepMatters

    The article is just letting people know about how important sleep is and that is all. Lack of sleep does not lead to heart disease, but the main effect of lack of sleep, as some of you mentioned, is the lack of energy. Without your body getting enough sleep to regenerate itself you will simply not have enough energy to go through the day. This causes people to eat to stay awake, drink sugar-laden liquids, etc., to keep the mind and body going. Healthy fuel is simply not enough to keep the mind going at a speed necessary for daily living/working. GET MORE SLEEP and you will live a better life. (Then maybe we could all ask our American bosses for more time off like the rest of the world. Remember we are only about 250 years old as a nation while the rest of the world is thousands of years old. We'll get there in time.)

    February 10, 2011 at 11:22 | Report abuse | Reply
  4. At 45 Degrees North

    Americans have the highest GDP. I do not think it is from sleeping half the day away.

    February 10, 2011 at 11:22 | Report abuse | Reply
    • Anonymous

      Did you know that healthcare-related expenses account for 16% of that precious GDP? 😉 This also means the GDP is absolutely unfit as an indicator of the welfare nor the wellness of a country, contrary to popular beliefs...

      See http://en.wikipedia.org/wiki/Health_care_in_the_United_States

      February 11, 2011 at 04:30 | Report abuse |
  5. Dude who hasn't slept enough for the past 25+ years

    Good health only means that you're dying at the slowest possible rate...

    February 13, 2011 at 23:36 | Report abuse | Reply
  6. mclj2011

    As a chronic night owl and forced early riser, I can definitely say that when I get at least 7 hours of sleep, I feel much more productive and alert the next day. The nights when I get 4-5 hours of sleep, I feel really sluggish the next day. If you think about it in terms of the rest your body needs to recharge (especially if your day is stressful) then it makes sense that sleeping less than required could have a long-term effect on health.

    February 20, 2011 at 20:00 | Report abuse | Reply
  7. smoker zippy

    @scott, if you cant sleep if you dont smoke, and not sleeping gives you about a 50% chance of dying from heart disease. i say start smoking again.

    February 21, 2011 at 10:21 | Report abuse | Reply
  8. TurtleAlWert!

    What the eff man! So many studies all around that say EVERY effin thing I do is going to kill me quick! So many studies and so little real verifiable data. Who the F even pays for these studies? And who checks if the results are correct? And what about vested interest disclosures?

    February 21, 2011 at 12:06 | Report abuse | Reply
  9. jay

    I think the writer of this article needs more sleep...

    February 21, 2011 at 16:17 | Report abuse | Reply
  10. steve pipkin

    I recently made a list of behaviors that make me feel better. I prioritized them and am trying to make them habits. I determined that the most important on the list is to get 8 hrs of sleep a night. If I get 8 hrs of sleep it is easier to engage in other good habits. I make better choices when I am rested.

    I apologize for being somewhat off topic.

    February 22, 2011 at 00:50 | Report abuse | Reply
  11. Hemwattie

    I would like to read the study itself – because this is a very poorly written article..i mean it tells you that getting less than 6 hours of sleep gives you a 48% chance of developing heart disease – but it doesnt tell you if you do get 6 hours or more what your chances are of developing heart disease. Also some ppl function normally on 5 hours of sleep – not because they force themselves to stay up...does the study discriminate against those who stay up late via caffeine and other stimulants and those who naturally just sleep less? Is there a discrimination btwn those who are under high stress and thus sleep less and those who again just normally function best with less sleep? Also I know when I stay up late for exams and to reach a deadline...i eat utter crap – high calorie foods to keep myself up...could that not contribute to the hormonal changes? There is not enough information in the article to make any definite conclusions – unless your apneic...or you're the kind of person that needs 8-10 hours of sleep to function optimally. There are people in this world who do not fall under those categories however.

    February 22, 2011 at 19:49 | Report abuse | Reply
  12. becks

    Lame article. I'm a college student – we DON;T sleep. Napping is the way to go. I try to get at least a 2-3 hour nap in if I get less than 6 hours of sleep.

    February 23, 2011 at 05:10 | Report abuse | Reply
  13. Dr. Joel

    Sandra–more responsible reporting of statistics, please. The study doesn't say people who sleep less than 6 hours have a 48% chance of developing or dying from cardiovascular disease. It says that they have a 48% GREATER risk compared to those who sleep longer. If the risk for >6hour sleepers is 2%, then the risk for short-sleepers is 2.96%% (I made up that number).

    February 28, 2011 at 23:18 | Report abuse | Reply
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Get a behind-the-scenes look at the latest stories from CNN Chief Medical Correspondent, Dr. Sanjay Gupta, Senior Medical Correspondent Elizabeth Cohen and the CNN Medical Unit producers. They'll share news and views on health and medical trends - info that will help you take better care of yourself and the people you love.