While rigorous exercise can promote heart palpitations in active people, those relaxing or lying down can also suffer heart arrhythmia or heart racing due to reasons such as excess caffeine, drugs, stress or decreased levels of iron or potassium. Such instances of irregular heart rhythms can be controlled by dietary shifts and stress-reduction activities. Other triggers, however, may require medical intervention to end heart palpitations when lying down. These triggers include a malfunctioning thyroid, heart disease and asthma.
Select drugs taken to alleviate health issues can temporarily cause palpitations when lying down. Medication prescribed to treat diseases of the heart valve or hypertension, for example, can cause people to experience heart flutters even when they are not exerting themselves. Even an antihistamine, a popular type of medication taken to treat allergies, has been linked to palpitations. Over-the-counter decongestants, sleeping aids and other cold remedies can also lead to similar palpitations, as can diet pills with stimulants such as ephedrine or caffeine.
Caffeine in products other than diet pills may be a problem for individuals, even if they consider themselves completely healthy. Thus, excess coffee, chocolate or tea may induce palpitations when lying down. Limiting consumption of these items may control the issue, although some people highly sensitive to palpitations when lying down choose to avoid caffeine altogether.
When the body is low in electrolytes such as magnesium or potassium, a person might experience palpitations when lying down. Electrolyte imbalances can be reversed through vitamin supplements or consumption of blackstrap molasses, which is high in minerals. Molasses can also raise iron levels for women who suffer heart palpitations because of anemia linked to iron deficiency. The loss of electrolytes is typical after excess perspiration whether through warm weather or robust exercise. In such cases, individuals can also consume special electrolyte-enhanced sports drinks to replenish lost minerals.
If someone experiences palpitations but can rule out pharmaceuticals, caffeine and electrolyte depletion as causes, the problem might be stress. Medical authorities cite anxiety, emotional trauma and high levels of frustration as factors that can cause a racing heart or one that skips beats. Pilates and Eastern mind-body meditation rituals such as tai chi or yoga are often encouraged as effective stress-relieving practices.
People with heart disease and extremely high blood pressure are most vulnerable to episodes of palpitations felt during rest. Physicians may have to alter medical treatment for these patients or place them under hospital observation. Tests like echocardiograms can help medical professionals analyze heart activity and detect a faulty rhythm. In sustained cases of heart palpitations when lying down, emergency medical assistance should be sought.