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Sleep Disturbances: Hearts at Risk

 
Sleep Disturbance and Stress
Sleep Disturbance and Weight Gain
Sleep Apnea and Stroke
Sleep Apnea and Heart Disease
Video: The Science of Sleep interview with Steven M. Scharf, MD, PhD, University of Maryland School of Medicine



Sleep Disturbance and Stress
Experts believe that almost 50% of all sleep problems are due to stress. Work-related issues followed by family and children-related issues top the list of what keeps America up at night. As a result, needed leisure is squeezed into those critical hours once reserved for sleep.

However, adequate sleep is crucial to proper brain function - no less so than air, water, and food - but stress can modify sleep-wakefulness cycles. Researchers have found that metabolic and endocrine changes resulting from a significant sleep debt mimic many of the hallmarks of aging. Chronic sleep loss may not only hasten the onset but could also increase the severity of age-related ailments such as diabetes, hypertension, obesity, and memory loss.

Sleep researchers have discovered that the brain needs time to erase or sift through the events of the day, just like a computer needs to clean its hard drive to create space for the next day's events. Often, the nighttime is the only time some allow for this needed activity. So instead of sleeping, a stressed brain seems to race as it goes over the stressful events of the day. Obviously, finding time and using effective methods for relieving stress is the best way to improve healthy sleep

The most important thing to remember about relieving stress is that our bodies need time to work out the effects of stress. Although it is not possible to control every factor that contributes to stress, it is possible to get the sleep we need so that we feel less cranky and more productive the following day. A consistent regimen is critical in this situation because it creates an expectation of stress release. Effective strategies include:

  • Scheduling time to work through the stress and finding ways to eliminate problems so they don't arise when you're trying to sleep. Try to deal with worries and distractions several hours before bedtime.

  • Meditating before going to bed

  • Engaging in daily exercise (but not 4 hours before bedtime)

  • Avoiding caffeine and other stimulants before bedtime

  • Avoiding alcohol within 4 hours of bedtime as alcohol interrupts and fragments sleep

  • Taking warm bath and listening to relaxing music before bedtime

  • Avoiding watching TV before bedtime

  • Keeping regular sleep hours. Keep your biological check by going to bed around the same time each night and waking up close to the same time each morning -- even on weekends.



Sleep Disturbance and Weight Gain
Scientists have found that sleep deprivation increases levels of a hunger hormone the effects of which may lead to overeating and weight gain. It could explain why so many Americans who are chronically sleep-deprived also are overweight. And it could be part of the reason sleepy college students, new parents and shift workers pack on pounds.

We know the obesity epidemic is due to overeating - big portions, rich food and very little activity - but why do we crave too much of these rich foods? It may be because we are sleep-deprived and unable to curb our appetites. In fact an estimated 63% of American adults do not get the recommended eight hours of sleep a night, according to the National Sleep Foundation. In fact, the average adult gets 6.9 hours of sleep on weeknights and 7.5 hours on weekends, for a daily average of seven hours. There are 80 types of sleep disorders of which a common and frequently undiagnosed one is sleep apnea that is linked to obesity.

Sleep deprivation activates a small part of the hypothalamus, the region of the brain that also is involved in appetite regulation. A critical hormone involved in regulating food intake is known as leptin. During sleep, leptin levels normally rise. But leptin levels are also markedly dependent on sleep duration.

During periods of sleep deprivation low leptin levels tell the brain there is a shortage of food and increase appetite. Indeed, researchers at the University of Chicago School of Medicine, examined the effect of sleep deprivation on this hormone and found that sleep-deprived men who had the biggest hormonal changes also said they felt the most hungry and craved carbohydrate-rich foods, including cakes, candy, ice cream, pasta and bread. Those who had the smallest changes reported being the least hungry.

Sometimes the best way to treat obesity can be to treat an underlying sleep problem such as sleep apnea, of which a major symptom is snoring. For example, successful treatment of sleep apnea {usually with nasal continuous positive airway pressure (CPAP)} may reduce sleepiness and then motivate one to effectively lose weight, which will in turn help the obesity and the sleep apnea. So if you are overweight or obese and sleep poorly or feel tired during the day, what should you do?

Talk to your primary care clinician about a referral to a sleep center in order to get a diagnosis. After determining the diagnosis, discuss with your healthcare provider undertaking a weight loss plan. After losing at least 10% of your body weight, consider undertaking another sleep study to determine further treatment.



Sleep Apnea and Stroke
A number of studies have established that moderate to severe cases of the nighttime breathing problem known as obstructive sleep apnea significantly increases the risk of suffering a stroke. It is estimated that about 10% of the population have undiagnosed sleep apnea. Further, almost 75% of stroke sufferers have sleep apnea and have significantly worse functional outcomes after stroke than do patients without apnea.

In obstructive sleep apnea, a person's airway narrows, or totally collapses during sleep. As a result, a person stops breathing briefly numerous times throughout the night. The person's sleep is interrupted often, which may cause excessive daytime sleepiness or even high blood pressure.

One reason sleep apnea may increase stroke risk is that it has been shown to cause high blood pressure, which is the most common risk factor for stroke. Another possible reason is that when a person stops breathing, the lack of oxygen kicks in the body's "fight or flight" response, which increases adrenalin production. The blood pressure goes up and the blood becomes more clottable. The blood clots in the brain cause a stroke.

A recent clinical study of 1,475 people found that those with moderate to severe sleep apnea at the beginning of the study were 3 to 4 times more likely to have a stroke than a comparable group of patients without sleep apnea during the next four years. The patients in the study were defined as having moderate to severe obstructive sleep apnea if their breathing stopped or slowed at least 20 times per hour of sleep.

This study provides yet another reason why it's important to treat sleep apnea, especially given the fact that assessment and treatment of sleep apnea is not typically a part of standard therapy for stroke patients. Many stroke patients have snoring and daytime fatigue as symptoms of apnea. Despite recognition of these problems, until now awareness of sleep apnea as a factor that might contribute to functional disability in patients with strokes may be very low among health care professionals. The patient therefore, has to take a very proactive role.

One method of preventing stroke therefore is to treat the underlying sleep apnea, of which a major symptom is snoring and daytime fatigue. Successful treatment of sleep apnea {usually with nasal continuous positive airway pressure (CPAP)} may play a significant role in preventing stroke. Since a major symptom of sleep apnea is snoring during the night and excessive daytime sleepiness, it is important to establish that you have the correct diagnosis. It is therefore important to talk to your primary care clinician about a referral to a sleep center in order to get a diagnosis, especially if you are a stroke sufferer and have symptoms of apnea.



Sleep Apnea and Heart Disease
It is estimated that about 10% of the population have undiagnosed sleep apnea, which may be an underlying cause of heart disease. People with sleep apnea suffer from repeated obstructions of the throat during sleep. They literally can't breathe while sleeping. They must wake up in order to breathe (but they don't usually recall these awakenings). This repeated fragmentation of sleep patterns keeps them from having normal, restorative sleep. Recent research suggests that snoring itself may affect sleep quality and may respond to the same treatments used for apnea.

One way sleep apnea is linked to heart disease is through its effect on blood pressure. Research has shown that apnea patients with normal blood pressure run a risk of developing high blood pressure within four years. Hypertension is a major risk factor in the development of heart disease and stroke.

Apnea patients have higher levels of sympathetic nervous system (SNS) activity during both wake and sleep than patients without sleep apnea. Involuntary functions such as heart rate and blood vessel constriction are controlled by the sympathetic nervous system. In persons without apnea, there is usually a decrease in SNS activity and blood pressure falls when sleeping. However, during apnea events, the higher level of SNS activity constricts the blood vessels, while the heart rate also jumps, slamming blood into tight vessels. Blood pressure spikes of up to 250/150 have been seen during apneas.

Sleep apnea patients also have faster heart rates than non-apnea patients, even when awake, but have less variability in their heart rates. This combination of a less variable heart rate and greater variability in blood pressure is an indicator of potential cardiovascular problems.

Lastly, a condition known as central apnea may cause high blood pressure, surges of adrenaline, and irregular heart beats. Central apnea occurs without snoring and is not caused by obstruction, rather it is caused by the failure of the brain to signal for a breath.

Once again, a method of preventing heart disease therefore is to treat the underlying sleep apnea, of which a major symptom is snoring and daytime fatigue. Successful treatment of sleep apnea {usually with nasal continuous positive airway pressure (CPAP)} may play a significant role in preventing hypertension and heart disease. Since a major symptom of sleep apnea is snoring during the night and excessive daytime sleepiness, it is important to establish that you have the correct diagnosis. It is therefore important to talk to your primary care clinician about your sleep problems and take a proactive role. After losing at least 10% of your body weight, consider undertaking another sleep study to determine further treatment.




Grateful acknowledgement to Mahmood I. Siddique, D.O., FACP, FCCP, FAASM for contributing this page. Dr. Mahmood is a Clinical Associate Professor of Medicine at UMDNJ- Robert Wood Johnson Medical School and Medical Director of the SleepCare Center at RWJ Hamilton. He is also the President of the Institute for Sleep and Lung Diseases. He is board certified in Internal, Pulmonary, Critical Care and Sleep Medicine. He has received multiple “Excellence in Teaching” awards at RWJ Medical School. He was selected to be on the peer-nominated Best Doctors list in Better Living magazine in NJ. He is also co-author of the book, “How to Turn Anger into Love” (www.HowToTurnAngerIntoLove.com). He can be reached at: (609)587-9944; www.sleephealthdoc.com. (WHF Special Report 2007)

For more information about the science of sleep, go to The Sleep Science Center

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