The Beat Goes On: Hormones and Your Heart

The heart is a remarkable muscle, pumping steadily through every moment of life. Most of the time, we aren’t even conscious of its rhythm – the autonomic nervous system keeps it going without a second thought.

Despite this seeming independence, the heart is highly sensitive to chemical signals in our body, including hormones, the chemical messengers that travel through the bloodstream, coordinating everything from metabolism to mood. While essential for survival, fluctuations or imbalances in hormones can ripple through the body, influencing the heart’s rhythm, structure, and overall function.

The Broad Stroke of Hormones

Hormones affect how the heart beats, how blood vessels constrict or relax, and even how the heart muscle repairs itself after stress.

Hormones can influence the heart in several ways:

• Electrical signaling: Certain hormones impact ion channels in heart cells, which regulate the electrical impulses that trigger each heartbeat. Changes in these signals can make the heart more susceptible to arrhythmias.
• Structural remodeling: Hormones like estrogen and testosterone can influence heart muscle thickness, blood vessel flexibility, and even the formation of fibrous tissue.
• Metabolic effects: Thyroid hormones, cortisol, and sex hormones all interact with energy metabolism. Since the heart has high energy demands, shifts in metabolic signaling can affect cardiac efficiency and oxygen use.
• Stress response: Hormones released during stress, like cortisol and adrenaline, prepare the body for immediate action but can strain the heart when elevated chronically.

Hormones act as both caretakers and stressors for the heart. When balanced, they support steady rhythm, healthy contraction, and optimal blood flow. When out of balance, they can increase heart rate, stiffen blood vessels, or even alter heart muscle structure, laying the groundwork for cardiovascular conditions down the line. Understanding these relationships can help explain why some people develop heart rhythm disturbances, high blood pressure, or other cardiovascular conditions even in the absence of traditional risk factors.

Stress Hormones and the Heart

Our bodies are designed to respond to stress. When a threat or challenge arises – whether physical, emotional, or psychological – the adrenal glands release stress hormones like cortisol and adrenaline. These hormones trigger the classic “fight-or-flight” response: the heart races, blood pressure rises, and energy is mobilized so the body can react quickly. In the short term, this response is adaptive and protective.

However, chronic or repeated stress keeps these hormones elevated, putting additional strain on the heart. Persistent high stress hormone levels can:

• Raise blood pressure: Constant vasoconstriction and fluid retention increase the heart’s workload, prompting hypertension.
• Disrupt heart rhythm: Stress hormones can alter the timing of electrical signals in the heart, increasing susceptibility to arrhythmias like Afib.
• Drive structural changes: Chronic stress may contribute to remodeling of the heart muscle, which can impair efficiency and increase the risk of heart failure.

Multiple studies show that individuals with higher circulating stress hormones have a significantly increased risk of hypertension and major cardiovascular events compared to those with lower levels.1-3 This chronic hormonal pressure also affects heart rate variability (HRV), a measure of how flexibly the heart responds to daily demands; prolonged stress tends to lower HRV, reflecting a heart that’s less resilient and more prone to rhythm disturbances.⁴

Interestingly, women’s hearts may be particularly sensitive to stress hormones. Research suggests that fluctuations in estrogen interact with adrenaline, potentially altering cardiovascular responses during stress and increasing susceptibility to heart rhythm disturbances and other cardiovascular issues.⁵

While short bursts of stress hormones are protective, long-term elevation is a hidden hindrance. Finding healthy ways to manage stress is not only beneficial for stabilizing mental well-being, it’s also advantageous for sustaining a robust cardiovascular system.

Sex Hormones and the Heart

Sex hormones like estrogen, progesterone, and testosterone are usually thought of in terms of reproduction and fertility. But these hormones also influence how the heart and blood vessels function. The heart has receptors for both estrogen and testosterone, meaning it can respond directly to these chemical signals, which affect heart rate, rhythm, blood vessel tone, and even the structure of heart muscle tissue.

Estrogen, the primary female sex hormone, has multiple protective effects on the heart. It helps blood vessels relax, improves the efficiency of mitochondria (cellular energy factories), and shields the heart from oxidative stress-induced damage. Estrogen also prevents excessive scarring (fibrosis) in heart tissue and supports healthy electrical signaling to maintain a steady heartbeat.6

Progesterone helps blood vessels relax and supports healthy calcium handling in the heart and vessels. These effects help regulate blood pressure and maintain flexible, responsive arterial tissue.

Testosterone, the primary male hormone, strengthens heart contractions, helps manage calcium in heart cells, and supports blood vessel relaxation. Balanced testosterone levels can enhance heart function, while both low and excessively high levels may raise cardiovascular risk.⁶

Men and women experience the effects of these hormones differently. Men are more prone to heart disease earlier in life, whereas premenopausal women generally have greater resistance to acute heart stress and heart muscle damage, thanks largely to estrogen.

Fluctuations or deficiencies in sex hormones (typically from aging, menopause, stress, or medical conditions) can influence heart rhythm, blood vessel function, and heart structure. When estrogen levels drop, as they do in menopause, blood vessels may become stiffer and less able to relax, contributing to higher blood pressure. Reduced estrogen also diminishes its protective effects on heart cells, leaving the heart more vulnerable to oxidative stress, fibrosis, and irregular electrical signaling.

Conversely, very high estrogen levels can sometimes increase blood clot risk or contribute to fluid retention, placing additional strain on the heart.

Progesterone imbalances can also affect cardiovascular health. Low levels may reduce vascular relaxation and calcium regulation, contributing to higher blood pressure and less adaptable blood vessels.

Low testosterone in men has been linked to weaker heart contractions, impaired metabolism, and a higher risk of arrhythmias, while excessive testosterone (often from supplements or anabolic steroids) can increase blood pressure, promote irregular heart rhythms, and strain the heart muscle.

Before starting hormone replacement therapy, it’s wise to discuss your heart health with a doctor. Sharing any known heart conditions and cardiovascular symptoms, both before and during treatment, helps your practitioner make informed decisions about your therapy.

Thyroid Hormones and the Heart

Thyroid hormones, produced by the butterfly-shaped gland at the base of your throat, are the body’s metabolic regulators. As such, they have a direct connection with the heart, controlling heart rate, the strength of each heartbeat, blood pressure, and even cholesterol levels.

A drop in thyroid hormones causes hypothyroidism, sometimes causing the heart to slow down and blood vessels to lose some of their elasticity. It can also raise blood pressure and cholesterol, making arteries stiffer and harder to pump blood through. Reduced thyroid hormone can also decrease the heart’s pumping efficiency, leading to fatigue, fluid retention, and in some cases, heart failure. Slower heart rate (bradycardia), changes in electrical signaling, and impaired relaxation between heartbeats (diastolic dysfunction) are common cardiovascular effects of hypothyroidism.^7-8

Too much thyroid hormone, or hyperthyroidism, has the opposite effect – it pushes the heart to work harder. The heart beats faster and stronger, blood pressure may rise, and abnormal heart rhythms, such as atrial fibrillation, can develop. People may notice palpitations or chest discomfort, especially if they already have heart disease or stiff arteries. Hyperthyroidism increases cardiac output by raising heart rate, inducing stronger contractions, and dilating blood vessels, which can place undue stress on the heart over time.⁹

Keeping Heart Health In Check

Balancing hormones and managing stress can help support a strong, resilient heart. Factors like age and genetics are beyond control, but you do have power over your lifestyle choices.

• Prioritize stress management: Regular relaxation techniques like deep breathing, meditation, yoga, and other mindfulness practices can help keep stress hormones like cortisol in balance and reduce strain on the heart. Even short daily practices improve heart rate variability and overall cardiovascular resilience.
• Maintain a balanced diet: Nutrient-rich foods support hormone production and heart health. Include plenty of fruits, vegetables, whole grains, lean proteins, and healthy fats. Avoid excessive alcohol and limit highly processed foods and sugary drinks.
• Exercise regularly: Moderate physical activity helps regulate stress, supports healthy sex hormone levels, and improves circulation. Aim for at least 150 minutes of aerobic exercise weekly, complemented by strength training.
• Monitor hormone levels: Routine check-ups for thyroid and sex hormones can identify imbalances early. Work with a healthcare provider to interpret lab results and discuss treatment options if needed.
• Prioritize sleep: Consistent, quality sleep regulates stress, supports thyroid function, and balances sex hormones. Aim for 7-9 uninterrupted hours per night.
• Communicate with your doctor: Share symptoms like palpitations, fatigue, or sudden changes in weight or mood. Open discussion helps tailor interventions and prevent hormone-related stress on the heart.

Small, consistent modifications in daily life can help manage stress and hormonal balance, giving your heart the support it needs to stay strong over time.

Dr. Tordini is a part of Florida Medical Clinic Orlando Health

References

1. Tsai, S.-Y., Hsu, J.-Y., Lin, C.-H., Kuo, Y.-C., Chen, C.-H., Chen, H.-Y., Liu, S.-J., & Chien, K.-L. (2024). Association of Stress Hormones and The Risk of Cardiovascular Diseases Systematic Review and Meta-Analysis. International Journal of Cardiology Cardiovascular Risk and Prevention, 23. https://doi.org/10.1016/j.ijcrp.2024.200305.
2. National Heart, Lung, and Blood Institute. (2021, September 13). Study links high levels of stress hormones to increased blood pressure, cardiovascular events | NHLBI, NIH. Www.nhlbi.nih.gov. https://www.nhlbi.nih.gov/news/2021/study-links-high-levels-stress-hormones-increased-blood-pressure-cardiovascular-events.
3. American Heart Association. (2021, September 13). Elevated stress hormones linked to higher risk of high blood pressure and heart events. American Heart Association. https://newsroom.heart.org/news/elevated-stress-hormones-linked-to-higher-risk-of-high-blood-pressure-and-heart-events.
4. Lee, C. H., Shin, H. W., & Shin, D. G. (2020). Impact of Oxidative Stress on Long-Term Heart Rate Variability: Linear Versus Non-Linear Heart Rate Dynamics. Heart, lung & circulation, 29(8), 1164–1173. https://doi.org/10.1016/j.hlc.2019.06.726.
5. Yup, K. (2023, February 8). How the “Fight-or-Flight” Hormone Affects Women’s Hearts Differently. Medicine.yale.edu; Yale School of Medicine. https://medicine.yale.edu/news-article/how-the-fight-or-flight-hormone-affects-womens-hearts-differently/.
6. Willemars, M. M. A., Nabben, M., Verdonschot, J. A. J., & Hoes, M. F. (2022). Evaluation of the Interaction of Sex Hormones and Cardiovascular Function and Health. Current heart failure reports, 19(4), 200–212. https://doi.org/10.1007/s11897-022-00555-0.
7. Yamakawa, H., Kato, T. S., Noh, J. Y., Yuasa, S., Kawamura, A., Fukuda, K., & Aizawa, Y. (2021). Thyroid Hormone Plays an Important Role in Cardiac Function: From Bench to Bedside. Frontiers in physiology, 12, 606931. https://doi.org/10.3389/fphys.2021.606931.
8. Grais, I. M., & Sowers, J. R. (2014). Thyroid and the heart. The American journal of medicine, 127(8), 691–698. https://doi.org/10.1016/j.amjmed.2014.03.009.
9. Yamakawa, H., Kato, T. S., Noh, J. Y., Yuasa, S., Kawamura, A., Fukuda, K., & Aizawa, Y. (2021). Thyroid Hormone Plays an Important Role in Cardiac Function: From Bench to Bedside. Frontiers in physiology, 12, 606931. https://doi.org/10.3389/fphys.2021.606931.