Is Heart Disease Keeping You Awake at Night? Learn to Reclaim Your Sleep
Your diseaseóor the medications you take for itómay affect your ability to sleep normally. But there are strategies that can help.
Physicians have known for years that obstructive sleep apnea, a condition that causes people to awaken countless times at night gasping for air, raises the risk of heart attack and sudden cardiac death. But the connection between sleep disorders and cardiovascular diseases runs much deeper. The most common sleep disorders—sleep apnea and insomnia—are associated with an array of adverse cardiovascular outcomes.
“It’s very likely a bidirectional relationship: Sleep-disordered breathing can lead to cardiovascular disease. Once cardiovascular disease develops, it can be a perpetuating factor for sleep disorders,” explains Reena Mehra, MD, Director of Sleep Disorders Research in the Sleep Center of Cleveland Clinic’s Neurologic Institute.
Heart Failure and Poor Sleep
Up to 50 percent of heart failure patients develop sleep apnea, which fragments sleep and contributes to insomnia. Multiple arousals during the night cause fatigue and sleepiness during the day.
All reasons for this relationship are unknown. However, uncontrolled heart failure causes fluid accumulation in the body. Fluid in the neck further obstructs breathing, making sleep apnea worse. Constant interruption of breathing during the night lowers blood oxygen levels, raising the amount of carbon dioxide (CO2) in the blood. This worsens sleep quality.
“We also know that heart failure increases the fight-or-flight response, which could contribute to poor sleep,” says Dr. Mehra.
Heart failure medications don’t always help, either. Beta blockers, which are used to lower blood pressure and reduce the workload of the heart, generally make people feel fatigued. Conversely, they cause insomnia in some patients.
Diuretics interfere with sleep by causing patients to awaken several times a night to urinate.
Arrhythmias Tied to Sleep Disorders
The link between arrhythmias and sleep apnea may be more surprising. However, sleep apnea is known to trigger irregular heartbeats. “We are just starting to discover why, but it appears that there are a variety of reasons including alterations in the fight-or-flight response mechanisms, low oxygen levels, direct mechanical influences on the heart due to changes in pressure inside the chest and an increase in CO2 likely contribute to arrhythmia risk,” Dr. Mehra explains. “It appears that if patients with atrial fibrillation are treated for sleep apnea before they undergo treatment for their arrhythmia, it reduces the likelihood the atrial fibrillation will recur.”
Impact of Sleep on Risk Factors
Sleep apnea elevates blood pressure. It affects insulin production and glucose metabolism, raising the risk of type 2 diabetes. It also increases the desire to eat high-carbohydrate foods, which can lead to obesity.
Patients with sleep apnea tend to develop the dangerous type of atherosclerosis, in which soft plaques prone to rupture form in multiple vessels. This increases their risk of having a fatal or nonfatal heart attack by 30 percent over several years.
But you don’t have to have a bona fide sleep disorder to develop cardiovascular disease or its risk factors. In September 2016, the American Heart Association/American Stroke Association released a statement explaining that consistently sleeping fewer than seven hours or more than nine hours creates a progressive risk of cardiovascular disease and mortality.
“There is a U-shaped distribution in the relation of sleep duration and several adverse health outcomes, with seven to nine hours representing the sweet spot,” says Dr. Mehra. “We don’t fully understand the reasons for this, but the findings are consistent in population-based studies.”
Short sleepers may not be getting the full benefits that a proper sleep provides. They also tend to have higher levels of inflammatory markers in their blood. Increased inflammation is associated with heart attack and stroke. Stroke risk is also elevated by frequently interrupted sleep.
The negative impact of too much sleep is more of a mystery. “These people might not be getting good quality sleep,” Dr. Mehra suggests.
Talking Sleep with Your Doctor
When your quality of life is adversely affected by problems sleeping at night, staying awake in the daytime or concentrating, or if you have become unusually irritable, tell your doctor.
“There’s a high prevalence of sleep disorders in heart disease, so you should be aware of the signs. These need to be investigated,” says Dr.†Mehra.