We often think of our hearts as steady metronomes, keeping a reliable rhythm in our chests. In reality, the heart is much more dynamic – it maintains a rhythm, yes, but its pace continually shifts to meet the changing demands of the body. It speeds up when you exercise, slows down during rest, and adapts seamlessly to life’s emotional and physical ups and downs.
Challenging this adaptability are internal stressors. Ranging from poor diet to chronic inflammation, they can tip the balance, making it harder for the heart to maintain a healthy rhythm and regulate its pace.
One of the hidden culprits behind this imbalance is oxidative stress, a state in which harmful molecules called reactive oxygen species (ROS) overwhelm the body’s natural defenses. Our bodies deal with a natural flux of ROS daily, but when too many accumulate over time, they can damage cells, interfere with normal heart processes, and make the heart’s rhythm more vulnerable to irregularities.
Recent research shows that oxidative stress affects not only the structure of the heart but also how reliably it beats. This can lead to potentially dangerous rhythm problems, known as arrhythmias, and reduce the heart’s ability to respond to everyday demands.1-2
What is Oxidative Stress?
Every day, your cells produce molecules known as reactive oxygen species (ROS), also referred to as free radicals. Problems arise when ROS accumulate faster than the body can neutralize them (via natural and supplemental antioxidants). This excess creates oxidative stress, which can damage cells, proteins, and even DNA. Think of it like rust (the oxidation of iron) forming on machinery: over time, it compromises how well everything functions. In the heart, oxidative stress can interfere with the cells that control electrical signals, which are essential for keeping a consistent, healthy heartbeat.
Oxidative stress doesn’t just appear out of nowhere – it often builds up due to lifestyle and environmental factors. Poor diet, smoking, pollution, chronic psychological stress, high blood sugar, and even intense exercise without proper recovery can increase ROS levels. Age is also a factor: as we get older, our natural antioxidant defenses tend to decline, making it easier for oxidative stress to take hold.
The effects of oxidative stress are widespread throughout the body, but the heart is particularly sensitive. When ROS overwhelm heart cells, they can alter how electrical signals travel, how the heart contracts, and how it recovers after stress. Over time, these changes can increase the heart’s susceptibility to rhythm disturbances, even in individuals without apparent heart disease.3
Effect on Heart Rhythm and Cardiovascular Health
A delicate electrical system maintains your heart’s rhythm, and one that’s functioning properly times each beat just right, keeping blood flowing efficiently. But oxidative stress can throw this system off balance.
One of the most direct ways oxidative stress affects the heart is by interfering with ion channels, the tiny gateways in heart cells that control electrical signals. When these channels are altered, signals can become irregular, which may trigger arrhythmias —abnormal heartbeats that range from brief skipped beats to life-threatening rhythms, such as ventricular tachycardia or fibrillation. These dangerous arrhythmias are often linked to heart damage from conditions like chronic ischemia or heart attacks. Oxidative stress can make the heart more vulnerable even in otherwise healthy individuals.
Oxidative stress also impacts heart rate variability (HRV), a measure of how much the time between heartbeats fluctuates. Like we mentioned at the beginning, a healthy heart isn’t perfectly steady; it naturally speeds up and slows down to respond to activity, stress, and rest. This flexibility, or high HRV, is a sign of good cardiovascular health. Studies show that individuals with higher oxidative stress have lower HRV, indicating that their hearts are less adaptable and more prone to rhythm disturbances.5
Oxidative stress can also lead to structural changes in the heart. Excess ROS promotes inflammation, fibrosis (scar tissue formation), and impaired communication between heart cells through gap junctions. Gap junctions are like tiny bridges that connect heart cells, allowing electrical signals to pass smoothly from one cell to the next. When these bridges are damaged, it creates areas of the heart that conduct electricity more slowly or unevenly, setting the stage for irregular beats and even dangerous re-entry circuits that perpetuate arrhythmias.6 A disruption of reentry circuits is a situation where electrical signals loop back on themselves instead of moving forward normally, triggering rapid or irregular heartbeats (e.g., arrhythmias).
The effect of oxidative stress on the heart is multifaceted: it disrupts the electrical signals, reduces heart rate flexibility, and contributes to structural changes, all of which increase the risk of arrhythmias and reduce the heart’s ability to respond to everyday demands. Over time, these changes can lead to chronic heart conditions such as heart failure, increased susceptibility to sudden cardiac events, reduced exercise tolerance, and higher blood pressure. Oxidative stress may also promote vascular damage, contributing to atherosclerosis and further compromising blood flow to the heart and other organs.
What Can We Do About Oxidative Stress?
Our bodies will come under duress (as in illness and aging), and life will throw curveballs – that’s unlikely to change. What we can influence is what we expose ourselves to, giving our hearts the strength to handle those inevitable missteps.
1. Eat a Heart-Healthy, Antioxidant-Rich Diet
Certain nutrients help neutralize ROS and reduce oxidative stress. Fruits and vegetables, especially those rich in vitamins C and E, carotenoids, and polyphenols, like berries, leafy greens, and colorful vegetables, are cell-protecting metabolic allies. Other compounds, like sulfur-containing amino acids found in garlic and onions, as well as taurine from protein sources, may also support healthy heart rhythms.7
2. Stay Physically Active… but Balance Intensity
Exercise strengthens the heart and boosts antioxidant defenses. Moderate aerobic activity, such as walking, swimming, or cycling, helps maintain flexible heart rhythms, but too much high-intensity exercise without recovery can temporarily increase ROS. Stay extra hydrated and let your body rest between workouts.
3. Manage Stress
Chronic stress increases ROS and disrupts heart rhythm. Practices such as meditation, yoga, deep breathing, or even brief moments of daily mindfulness can help reduce oxidative stress and improve heart rate variability.8 If life feels overwhelming or you’re struggling to cope, consider reaching out to a behavioral health professional. Talking with someone can provide perspective, support, and practical tools to help you manage stress and protect your heart.
4. Prioritize Sleep
Quality, not just quantity, of sleep allows the body to repair and restore balance. Poor or fragmented sleep can raise oxidative stress levels and affect heart rhythm. Over time, disrupted sleep patterns can erode the body’s natural defenses, making it more difficult to regulate stress and inflammation. Consistently prioritizing deep, restorative rest gives the heart (as well as the brain, muscles, everything) the recovery time it needs to function.
5. Reduce Lifestyle Risk Factors
Smoking, excessive alcohol, and diets high in processed foods or added sugars all contribute to oxidative stress. These habits flood the body with free radicals while depleting its natural antioxidant defenses, creating a cycle of damage that strains the heart. Do your body a favor by shifting toward whole foods and moderation.
6. Consider Targeted Medical Support
For those with higher risk or existing heart conditions, medical interventions, such as medications that influence ROS or support ion channel function, might help. Studies on antioxidant supplements have mixed results, but ongoing research is exploring therapies that more directly address oxidative stress in the heart.9
Life will never stop testing us, but we can build resilience through nourishing habits, supportive environments, and mindful choices. Proactive behaviors will help to keep a steady rhythm even when life is anything but steady.
Antioxidant Allies
Antioxidants neutralize excess ROS before they can damage cells. Our bodies naturally produce their own antioxidants, such as glutathione and certain enzymes, which act as an internal clean-up crew against everyday oxidative stress. But this built-in system can get overwhelmed, especially with aging, illness, or constant exposure to stressors like pollution, poor diet, or smoking.
Colorful fruits and vegetables, nuts, green tea, and even dark chocolate provide natural antioxidant compounds. At the same time, supplements like vitamin C, vitamin E, and CoQ10 can support the body when diet alone isn’t enough. Consuming antioxidant-rich foods, and taking supplements when appropriate, restores balance and protects the heart from cellular wear and tear.
A heart that can bend without breaking is one that’s protected by daily choices as much as by medicine. While science continues to explore new therapies, the most accessible tools are already in our hands: sleep, movement, nutrition, and mindful living.
Dr. Tordini is a part of Florida Medical Clinic Orlando Health
References
- Adameova, A., Shah, A. K., & Dhalla, N. S. (2020). Role of Oxidative Stress in the Genesis of Ventricular Arrhythmias. International journal of molecular sciences, 21(12), 4200. https://doi.org/10.3390/ijms21124200.
- 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.
- Sovari A. A. (2016). Cellular and Molecular Mechanisms of Arrhythmia by Oxidative Stress. Cardiology research and practice, 2016, 9656078. https://doi.org/10.1155/2016/9656078.
- Adameova, A., Shah, A. K., & Dhalla, N. S. (2020). Role of Oxidative Stress in the Genesis of Ventricular Arrhythmias. International journal of molecular sciences, 21(12), 4200. https://doi.org/10.3390/ijms21124200.
- 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.
- Sovari A. A. (2016). Cellular and Molecular Mechanisms of Arrhythmia by Oxidative Stress. Cardiology research and practice, 2016, 9656078. https://doi.org/10.1155/2016/9656078.
- Adameova, A., Shah, A. K., & Dhalla, N. S. (2020). Role of Oxidative Stress in the Genesis of Ventricular Arrhythmias. International journal of molecular sciences, 21(12), 4200. https://doi.org/10.3390/ijms21124200.
- 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.
- Sovari A. A. (2016). Cellular and Molecular Mechanisms of Arrhythmia by Oxidative Stress. Cardiology research and practice, 2016, 9656078. https://doi.org/10.1155/2016/9656078.