Since the heart performs the crucial task of supplying blood to every cell in the body, it must beat in a systematic and controlled manner. The heart’s electrical system controls the rate and rhythm of the heartbeat. Arrhythmias, or abnormal heart rhythms, interfere with the heart’s ability to pump blood efficiently.1
Arrhythmias that strike when you’re asleep may occur due to low blood oxygen levels due to sleep-disordered breathing or exaggerations of normal sleep-related changes in heart rhythm. Arrhythmia during sleep can make the heart beat irregular, or too fast or too slow. Although exercise benefits cardiovascular health, it can occasionally trigger arrhythmia episodes.
What Arrhythmia During Sleep Or Exercise Means
Since heart arrhythmias may indicate a health condition, it is vital to understand why they occur during sleep.
1. You Could Have Sleep-Related Breathing Disorders
Sleep-related breathing disorders refer to a spectrum of breathing anomalies that interfere with the normal frequency or depth of breathing during sleep. A common sleep-disordered breathing syndrome is obstructive sleep apnea (OSA) characterized by intermittent episodes of upper airway obstruction during sleep. Arrhythmias are common in people with OSA.2 Factors such as male gender, aging, and obesity contribute to the risk for OSA.
Central sleep apnea, which is caused by abnormalities in the central nervous system is another sleep-disordered breathing syndrome that is associated with arrhythmias. It’s sometimes attributed to obesity hypoventilation syndrome, which reduces lung movement due to compression of the chest cavity. Arrhythmias may also occur due to an upper airway resistance syndrome, which is caused by conditions that inhibit air flow through respiratory passages.
2. You Might Have Low Blood Oxygen
A common cause of arrhythmias in people with sleep-disordered breathing syndromes is hypoxia or low blood oxygen. When your breathing rate reduces or stops, the blood oxygen level also drops. This results in many bodily changes that increase your heart’s irritability and causes an arrhythmia. Researchers suggest that hypoxia, rising carbon dioxide levels, changes in internal chest pressure, and stimulation of “fight-or-flight” reflexes as potential triggers of nocturnal arrhythmias in people with sleep-disordered breathing syndromes.
3. You Could Have Heart Abnormalities
As we transition from a wakeful to sleep state, the nervous and cardiovascular systems begin to change. These changes are more profound when you transition from one stage of sleep to another. While heart rate normally reduces during some sleep stages, in rapid eye movement (REM) sleep, your heart rate increases.
Experts suggest that these normal fluctuations in rhythm can become amplified in some people, especially among those with underlying cardiac or respiratory diseases or subtle electrical anomalies in their heart. This results in excessively slow rhythms, sleep-related atrial fibrillation, and other arrhythmias.
4. Your Prescription Drugs Could Be The Culprit
Besides sleep-disordered breathing, other factors that such as prescribed medications can change your heart’s electrical activity during sleep causing nocturnal arrhythmia. Many antipsychotic and antidepressant drugs have been linked to arrhythmias and even sudden cardiac arrest. Though tricyclic antidepressants like imipramine (Tofranil) and nortriptyline (Pamelor) are often consumed before bedtime to enhance their sedating effects, these medications may also trigger nocturnal arrhythmias.3
5. It Could Raise The Risk Of Mortality
Various studies have found that sleep-disordered breathing syndromes, especially obstructive sleep apnea, are associated with a higher mortality risk. Heart failure and high blood pressure are frequently observed in people with sleep apnea. A study published in The New England Journal of Medicine showed that OSA increases the risk of stroke or death from any cause. A higher occurrence of arrhythmias may be the underlying cause of sudden cardiac death during sleep, which is more frequent among people with sleep-related breathing disorders.4
Symptoms And Causes Of Arrhythmia
Symptoms
Although not many external signs are noticed during arrhythmia episodes, some common symptoms are often observed. According to the National Heart, Lung and Blood Institute, common symptoms include,
- Sweating
- Anxiety
- Slower heartbeat
- Breathing difficulties
- Pauses between heartbeats
- Sensation of your the heart fluttering or skipping
- Weakness and chest pain
- Dizziness or lightheadedness during exercise-related arrhythmias
Causes
- Arrhythmias can occur due to various causes that include heart disease, electrolyte abnormalities, metabolic disorders or toxins.
- Even competitive sports can invoke a cause the body to go into a state called hyperarousal, or the acute stress response, which may interfere with the heart’s electrical activity, leading to heart arrhythmias.
- Stress due to excessive or intense exercise can increase the blood pressure, which releases stress hormones and triggers arrhythmias.
- Smoking and consuming caffeine before or after exercise can also lead to arrhythmias.
- Certain medical conditions like an underactive thyroid, coronary heart disease, and Wolff-Parkinson-White syndrome can also cause arrhythmias.
Tips To Prevent Arrhythmia
- Don’t overexert yourself while exercising and take breaks whenever required (especially if you feel your heart is behaving abnormally).
- Relax your body and mind by slowly by reducing your activity after exercise to bring your heart rate back to normal. Take a slow 10-minute walk and stretch.
- Avoid exercises that cause heart arrhythmias.
- Avoid caffeinated beverages or foods and quit smoking.
- Chronic heart arrhythmias usually need an anti-arrhythmic medication to help control episodes.
- Never ignore heart arrhythmias, particularly if they are painful or chronically occur during or after exercise. If left untreated, heart arrhythmias can hinder blood circulation resulting in a stroke, blood clot or even heart failure.
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