How Does Sleep Apnea Affect the Heart?

People who have sleep apnea pause in their breathing while asleep. These pauses occur anywhere from 5 to 30 times an hour and last from a few seconds to up to a minute or longer. Snoring is often involved.^1,2

These pauses in breathing affect sleep quality and can lead to fatigue and drowsy driving. Research also shows that untreated sleep apnea leads to serious health problems, especially cardiovascular disease (CVD), obesity, stroke, and type 2 diabetes.^1,3

Diseases related to sleep apnea

Researchers are still learning about the effects that sleep apnea can have on your health, but they have noticed some trends. Multiple studies have shown that sleep apnea increases the risk of CVD and high blood pressure. It also increases your risk of death due to cardiac arrest. Those living with both sleep apnea and pre-existing conditions, like heart failure, are at a higher risk of death than those living with heart failure alone.⁴

Sleep apnea causes high blood pressure. High blood pressure caused by sleep apnea can lead to abnormal heart rhythms (arrhythmias). The heart has 4 chambers, and they must pump in a particular way to send blood through the lungs and then out into the body. Arrythmias mean that the heart is not working as it should. Less blood may move through the body so some cells may not get the oxygen they need. Arrhythmias can result in heart attacks, heart failure, or strokes.⁴

Sleep apnea is also associated with obesity, stroke, and type 2 diabetes. These disorders can also increase the risk of CVD.^1,3,4

How does sleep apnea increase your risk of heart disease?

Normally during sleep, your blood pressure and heart rate slow down and speed up at different times throughout the night. However, in sleep apnea, these cycles are thrown off.⁵

When you have a pause in breathing while sleeping, the body has an instinctual startle response. This wakes you up just enough to start breathing again. During each of these startle responses, your blood pressure and heart rate rise. This is another reflex to move more oxygen and blood throughout the body. Even with the reflexive rise in blood pressure, your body takes in less oxygen because of these pauses. This decrease in oxygen increases your risk of other diseases. Also, these spikes in blood pressure may last long after the pause in breathing. This is what is believed to cause high blood pressure.^1,2,4,5

Sleep apnea has dramatic effects on heart rate. A drop in oxygen activates the sympathetic nervous system, sending a ‘fight or flight’ message to the body. This response increases heart rate during pauses in breathing but also may increase heart rate while awake. The drop in oxygen can also cause the opposite effect, slowing the heart rate dangerously. This may lead to cardiac arrest and death.^4,5

Low oxygen stresses the body, causing it to send "danger" signals. These danger signals can trigger many other effects like inflammation and insulin resistance. Insulin resistance increases the risk of type 2 diabetes. Insulin resistance can also lead to obesity, another risk factor for CVD.^1,4,5

What should I do next?

The most recognizable symptom of sleep apnea is experiencing audible pauses in breathing during the night. Other symptoms may include heavy snoring, excessive sleepiness, poor concentration, or trouble staying asleep.^1,2

Researchers estimate that up to 85 percent of people living with sleep apnea have not been diagnosed. If you think you may have sleep apnea or are snoring, talk to your doctor.⁵

If you have been diagnosed with sleep apnea, follow your doctor’s instructions on how to use your CPAP machine. Scientists believe that using the CPAP machine allows the body to recover and heal the damage caused by sleep apnea.^2,4,5

However, it may take time to see the benefits of the CPAP because the body needs time to repair what could be years of damage. Treating sleep apnea as early as possible can prevent this damage before it leads to more serious diseases.^2,4,5