Thyroid-related palpitations happen because excess thyroid hormone directly stimulates your heart, making it beat faster and harder than normal. Stopping them requires a combination of treating the underlying thyroid condition, managing symptoms with medication, and making targeted lifestyle changes that reduce triggers. Some techniques can also slow your heart rate in the moment when palpitations strike.
Why Thyroid Problems Cause Palpitations
Your thyroid hormones don’t just affect your metabolism. They enter heart cells and change how genes in those cells are expressed, including genes that control how fast and forcefully the heart contracts. When thyroid hormone levels are too high (hyperthyroidism), the heart’s pacemaker cells become more excitable, and the muscle itself squeezes harder with each beat. This is a direct effect on the heart tissue, not just a stress response.
Excess thyroid hormone also increases the number of stimulatory receptors on heart cells, essentially making your heart more sensitive to adrenaline. That’s why palpitations from hyperthyroidism often feel worse during moments of stress, physical activity, or after caffeine. Your heart is already primed to overreact, and anything that adds adrenaline to the mix amplifies the problem.
Techniques That Help in the Moment
When palpitations hit and you need relief now, vagal maneuvers can help. These are physical techniques that stimulate the vagus nerve, which acts as a brake on your heart rate. They won’t fix the underlying thyroid issue, but they can interrupt a fast or irregular rhythm.
The Valsalva maneuver is the most common. Lie on your back, take a deep breath, then try to exhale forcefully with your mouth and nose closed for 10 to 30 seconds. It should feel like trying to push air through a blocked straw. A modified version works even better: do the same thing while sitting up, then immediately lie back and bring your knees to your chest, holding that position for 30 to 45 seconds.
The diving reflex is another option. While sitting, take several deep breaths, hold your breath, and submerge your entire face in a bowl of ice water for as long as you can tolerate. If that’s impractical, pressing an ice-cold wet towel or a bag of ice water against your face triggers a similar response. The cold activates a reflex that slows the heart.
Slow, controlled breathing on its own can also help. Inhale for four seconds, hold for four, exhale for six to eight. This won’t be as powerful as a vagal maneuver, but it shifts your nervous system toward a calmer state and can take the edge off milder episodes.
Medication for Thyroid-Related Heart Symptoms
Beta-blockers are the first-line treatment for controlling palpitations caused by hyperthyroidism. They work by blocking the stimulatory receptors on your heart that thyroid hormones have made overly sensitive. The result is a slower heart rate, less forceful contractions, and a noticeable reduction in the racing, pounding sensation.
Propranolol is the most commonly prescribed beta-blocker for this purpose because it’s nonselective, meaning it blocks stimulatory receptors throughout the body, not just in the heart. This helps with other hyperthyroid symptoms too, like tremor and anxiety. Most people need somewhere between 80 and 320 mg per day, split into multiple doses, though your doctor will start low and adjust based on your response.
If you can’t tolerate beta-blockers (common reasons include asthma or very low blood pressure), calcium channel blockers like diltiazem are an alternative for reducing heart rate.
These medications manage the symptom, not the cause. The palpitations will keep returning until the hyperthyroidism itself is treated, whether through antithyroid drugs, radioactive iodine, or surgery depending on the underlying condition.
Dietary Changes That Reduce Triggers
What you eat and drink can make thyroid palpitations noticeably better or worse. Two categories matter most: stimulants and iodine.
Caffeine and other stimulants amplify the adrenaline sensitivity that hyperthyroidism creates. Coffee, energy drinks, pre-workout supplements, and even large amounts of tea can push an already-fast heart rate higher. You don’t necessarily need to eliminate caffeine forever, but cutting back significantly while your thyroid levels are elevated makes a real difference in how often palpitations occur and how intense they feel.
Excess iodine is a less obvious trigger. Your thyroid uses iodine to manufacture thyroid hormones, so consuming large amounts of it gives an overactive thyroid more raw material to work with. High-iodine foods include seaweed, kelp supplements, iodized salt in large quantities, and certain shellfish. If you’re already hyperthyroid, reducing iodine intake can help prevent your hormone levels from climbing further.
Alcohol is worth mentioning too. It disrupts heart rhythm independently of thyroid function and can trigger palpitations on its own. Combined with hyperthyroidism, even moderate drinking can make episodes more frequent.
The Role of Magnesium
Magnesium is an electrolyte that plays a specific role in your heart’s electrical system. It helps regulate the timing of signals passing through the part of the heart that controls rhythm. When magnesium levels are low, those electrical signals move faster than they should, and your heart speeds up or beats irregularly. Magnesium deficiency is common in the general population, and it can make thyroid-related palpitations worse than they’d otherwise be.
The recommended daily intake for adults is 310 to 320 mg for women and 400 to 420 mg for men, depending on age. Many people don’t reach these levels through diet alone. Good food sources include dark leafy greens, nuts, seeds, beans, and whole grains. If you and your doctor determine a supplement makes sense, stick within the recommended range. Excess magnesium from supplements can cause its own problems, including low blood pressure, diarrhea, muscle weakness, and in severe cases, impaired kidney function.
Correcting a magnesium deficiency won’t cure hyperthyroid palpitations, but it removes one contributing factor and can reduce the frequency and severity of episodes while you’re addressing the thyroid itself.
Lifestyle Habits That Help Long-Term
Sleep deprivation raises baseline heart rate and makes the nervous system more reactive, both of which worsen palpitations. Prioritizing consistent, adequate sleep (seven to nine hours for most adults) gives your cardiovascular system a better foundation. If hyperthyroidism is disrupting your sleep, which it commonly does through insomnia and night sweats, that’s another reason to get the thyroid treated promptly.
Exercise is more nuanced. Regular moderate activity improves heart rate variability and cardiovascular health over time. But intense exercise while your thyroid levels are significantly elevated can be risky, since your heart is already working harder than normal. Most doctors recommend keeping exercise light to moderate until thyroid levels are closer to the normal range, then gradually increasing intensity.
Stress management matters because stress hormones (adrenaline and cortisol) compound the cardiac effects of excess thyroid hormone. Anything that lowers your stress baseline, whether that’s meditation, walking, or simply reducing commitments during treatment, can reduce the frequency of palpitation episodes.
When Palpitations Become an Emergency
Most thyroid-related palpitations are uncomfortable but not dangerous. However, a severe complication called thyroid storm can develop, particularly in people with untreated or poorly controlled hyperthyroidism. In thyroid storm, the heart rate can exceed 140 beats per minute, often accompanied by a high fever (104 to 106°F), agitation, confusion, and sometimes loss of consciousness.
If you experience a rapid heart rate combined with high fever, delirium, severe nausea, or yellowing of your skin or eyes, get to an emergency room immediately. Thyroid storm is life-threatening and requires hospital treatment. Infections, surgery, or suddenly stopping thyroid medication are common triggers.
Outside of thyroid storm, palpitations that come with chest pain, fainting, severe shortness of breath, or a heart rate that stays above 120 at rest for an extended period also warrant urgent medical evaluation. These can signal that hyperthyroidism is putting enough strain on the heart to cause structural problems like heart failure, which is reversible when caught and treated early.