Are Sleep Disorders Associated with Cardiac Death?

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According to the World Health Organization, ischemic heart disease and stroke were the two leading causes of death worldwide in 2016. Although the number of cardiovascular diseases (CVD) has decreased dramatically, diseases in this category are still the leading cause of loss of health and life.

Cardiovascular Disease, Fatigue, and Depression

In the U.S., according to the CDC’s Division of Heart Disease and Stroke Prevention, 1 in 3 deaths is due to heart disease, and $1 in 6 is spent on cardiovascular disease.

While the statistics are troubling, cardiovascular disease can also lead to nonfatal strokes, heart attacks, disability, serious illness and a lower quality of life. These conditions can lead to fatigue, depression and similar problems.

The American Heart Association tracks seven major health factors and behaviors that it believes increase the risk for heart disease and stroke. They call these “Life’s Simple 7,” which they measure to track progress toward their goal of improving the cardiovascular health of people in the United States.

Although all of the behaviors and risk factors in the Life’s Simple 7 are important to overall health, sleep problems are not included as contributing factors.

Pandemic affects Sleep Timing and Quality

In an interview with radio station KYW, Dr. Zeeshan Khan, pulmonary specialist at the Deborah Heart and Lung Center, discussed sleep disorders and their link to cardiovascular disease, especially in the midst of the current pandemic. He told the Reporter that the International Classification of Sleep Disorders lists at least 60 diagnoses in seven categories.

The two most common are insomnia and obstructive sleep apnea. With persistent poor sleep, a person can have altered judgment, mood swings and cognitive impairment. Khan also cited problems with the cardiovascular system and immunity in people who chronically get less than seven hours of sleep a night.

He warned that lack of sleep can lead to problems with overall health. He recommends that people should sleep an average of seven hours a night, but he also shared that in America, about 35% of people get less than that. “We’re kind of a sleep-deprived nation,” he said.

Symptoms of sleep disorders or insomnia can vary from person to person. Even if you take a 30-minute nap in the early afternoon, it won’t eliminate the sleep deficit. It may make you feel better at that moment, but it won’t affect the impact of sleep disorders on your overall health.

Inadequate Sleep Quality Is Associated with Cardiac Morbidity

When asked how long it should take to fall asleep, Khan replied that the average time is 15 to 20 minutes. However, the time to fall asleep increases when people take their smartphone or computer to bed with them. Using these devices can disrupt sleep in a number of ways, including keeping the mind busy at a time when it should be resting.

Khan advises using non-pharmacological treatments first to improve sleep, such as cognitive behavioral therapy, mindfulness, a consistent sleep routine and meditation. He also recommends staying away from medications, as they can be addictive and only treat the symptom of the sleep disorder, not the cause.

He also recommends abstaining from a nightcap to relax and fall asleep. That’s because alcohol before bed helps you fall asleep faster, but can have a long-term negative effect on sleep patterns. He stressed the importance of having a routine for falling asleep to activate the biological clock.

He also addressed the problems of sleep apnea, which often overlaps with snoring. In snoring, the upper airway narrows, causing vibrations in the mucous membranes. Although most people with sleep apnea snore, not all people who snore have sleep apnea.

If people with diabetes, heart disease, or other problems also snore, they should be evaluated for sleep apnea, especially if they have problems during the day. With sleep apnea, the supply of oxygen to the brain, heart and other organs is reduced during sleep. According to Khan:

Nearly every heart condition imaginable has been linked to sleep apnea. Heart disease, heart failure, arrhythmias, strokes … inflammatory problems such as diabetes, increasing obesity – the list could go on and on.

Sleep Disorders Linked to Nighttime Use of Technology

In a recent study published in Sleep Standards, researchers evaluated the results of a survey of 1062 people in the United States. The goal was to find out how technology was related to sleep disturbances.

A key finding was that 71.8% of respondents who reported sleep disruption also used technology shortly before going to bed. The researchers divided the participants into five age groups that represented the total number of respondents. These were:

  • Generation Z (under 25) – 22.3%
  • Millennials (26 to 40) – 44.8%
  • Generation X (41 to 55) – 23.8%
  • Baby boomers (56 to 76) – 8.9%
  • Silent Generation (older than 76) – 0.2%.

They also found that individuals under the age of 25 were most likely to suffer from sleep disorders. People with sleep disorders slept an average of five hours a night and spent up to 20 hours a day in front of a bright screen. Participants also reported using their tech devices within 30 minutes of bedtime: 70.2% watched TV, 59.4% checked social media, 31.8% checked email, and 32.9% played video games.

Of all participants, 57.8% reported using cell phones, which is higher than TV use at 18.5% or computer use at 14.2%. The highest percentage of participants in the survey suffered from insomnia (64.3%).

Although sleep apnea was the second most common disorder, it was a distant second at 14%. Other disorders mentioned in the survey included sleep paralysis, parasomnias, restless leg syndrome and narcolepsy. Although many experts like Khan recommend staying away from pharmaceuticals to treat insomnia, 51.2% of respondents reported taking sleeping pills, and 47.5% had tried other medications.

Sleep Deprivation is Associated with More Health Disorders

Fragmented or disturbed sleep is when you fall asleep easily but wake up during the night. This can happen frequently and you easily fall back asleep, or you may wake up and have trouble falling back asleep. This type of sleep pattern can trigger chronic inflammation that contributes to psychological and neurological problems.

Lack of sleep also affects the immune system, as fewer protective cytokines are available. In addition, sleep deprivation is associated with atherosclerosis, which is the buildup of plaque in the arteries. This can be referred to as “clogged” or “hardened” arteries and can lead to fatal heart disease.

The exact mechanism of how poor sleep triggers atherosclerosis was clarified in a study by UC Berkeley sleep researchers, who found that an increase in neutrophil and monocyte concentrations during fragmented sleep had an impact on atherosclerosis pathology. They wrote:

…these findings confirm a pathway in which the quality of human sleep, particularly the degree of fragmentation, increases white blood cells associated with inflammation, thereby conferring an increased risk of atherosclerosis. This is true both for sleep fragmentation over a week and for a single night, which predicts progressively higher CAC [coronary artery calcification] levels via a mediating association with elevated neutrophils.

Sleep deprivation has also been linked to the development of Alzheimer’s disease and other neurodegenerative disorders. A recent animal study from the Polytechnic University of Marche in Italy found that astrocytes in the brain begin to break down healthy nerve synapses during chronic sleep deprivation. The findings suggest that:

…that like many other stressors, prolonged sleep interruption can lead to a state of sustained microglial activation, potentially increasing the brain’s susceptibility to other forms of damage.

Average Number of Hours of Sleep Declines

For several years, Mattress Firm has commissioned a survey on sleep habits and the number of hours people sleep each night. The 2019 results show that Americans are sleeping less and less. They surveyed 3,000 adults about their sleep habits, satisfaction with their sleep, and frequency of sleep and naps. They compared these results to those from 2018.

What they found is a sad commentary on the speed at which modern society lives. It seems that getting at least six hours of sleep has become more difficult with each passing year. In 2018, the survey results showed that the average person slept six hours and 17 minutes each night, but in 2019 that time had dropped to 5.5 hours.

Experts currently recommend that adults between the ages of 18 and 65 sleep between seven and nine hours each night. In other words, most people sleep at least 1.5 hours less each night than the minimum experts believe is important for optimal health.

Not only is the number of hours of sleep important, but also the quality. Which makes it all the more disheartening to read that 25% of respondents said they had “consistently slept poorly” in 2019 as well.

Since the quality of sleep at night has declined, it makes sense that respondents said they took more naps in 2019 than in 2018, but while more naps were taken, the survey results suggest that there were many planned naps that were not taken.

The survey defined a “good night’s sleep” as “falling asleep quickly and sleeping through to morning.” There were about 120 nights that met this criterion. Americans are so desperate for a good night’s sleep that they are willing to “pay $316.61 for a single night of perfect sleep.” That’s $26.16 more than in 2018.

Interestingly, those who slept best were those who slept on their back or with a pet in bed. While side sleeping was the most common position in the survey, these were the same respondents who had the most difficulty falling asleep.

EMF Exposure Associated with Sleep Hours and Quality

As I’ve written before, your sleep quality can be affected by several factors, including your sleep patterns, the number of hours you sleep, and the light and electromagnetic pollution in your environment. If you’ve ever been camping, you may have noticed a change in your sleep quality. You probably had a deeper sleep and woke up more rested.

Two factors that contribute to sleeping better outdoors are drastically reducing artificial light and reducing electromagnetic fields (EMF). Your body clock is affected by melatonin levels, which in turn are affected by exposure to light at night. You could enjoy the same restful sleep by installing blackout blinds, using a sleep mask, and eliminating all light sources in your bedroom.

Electromagnetic fields can also affect sleep quality and cause oxidative damage during sleep. Consider turning off all electronic devices as well as your Wi-Fi modem and router at night to reduce exposure and improve your sleep quality. For more tips on how to improve the number of hours you sleep and the quality of your sleep, see “Top 33 Tips to Optimize Your Sleep Routine.”


1. World Health Organization, May 24, 2018

2. Journal of the American College of Cardiology, 2017;70(1)

3. Centers for Disease Control and Prevention

4. American Heart Association

5. KYW, September 18, 2020

6. Chest, 2014;146(5)

7. Sleep Standards

8. Digital Journal, September 17, 2020

9. Berkeley News June 4, 2020

10. Mayo Clinic

11. PLOS Biology, June 4, 2020

12. Journal of Neuroscience, 2017;37(21)

13. Mattress Firm

14. Study Finds, January 20, 2020

15. Sleep Health – Journal of the National Sleep Foundation, 2015;1(1):40

16. Journal of Sleep Research 1999;8:77

17. The Journal of Microscopy and Ultrastructure, 2017;5(4):167

18. American Back Centers