Running Too Much Can Backfire: Cardiologist Warns About Hidden Heart Risks

Running has long been promoted as one of the healthiest and most accessible forms of physical activity. It improves stamina, lowers the risk of chronic diseases, strengthens mental health, and is often the cornerstone of training regimens for young athletes. In India, as marathon culture and fitness challenges gain momentum, many fitness enthusiasts are logging impressive weekly mileage. But cardiologists are raising an important red flag: when taken to extremes, running can sometimes backfire on the very organ it aims to protect. Excessive and unstructured endurance training has been linked to myocardial fibrosis, a condition where scar tissue develops in the heart muscle, reducing its flexibility and long-term function.

"Myocardial fibrosis doesn't happen overnight. It's the result of years of repetitive micro-injuries to the heart muscles that don't heal properly because rest and recovery are neglected," says Dr Kumar Kenchappa, Consultant - Interventional Cardiologist, Manipal Hospital Hebbal. "This scarring makes the heart less efficient over time, particularly in young athletes who push themselves without balancing rest."

What Is Myocardial Fibrosis?

Myocardial fibrosis occurs when the heart muscle develops rigid, scar-like tissue. Normally, the tiny muscle injuries caused by intense workouts repair themselves with adequate rest. But in athletes who consistently overtrain without recovery, the healing process gets disrupted.

Dr Kenchappa explains: "The repeated strain and insufficient healing gradually transform into permanent scarring. This makes the heart less flexible, impairing its ability to pump effectively. Endurance athletes such as marathoners or ultra-distance runners are particularly at risk, given their prolonged training hours and high weekly mileage."

International studies support these findings. Research published in the Journal of the American College of Cardiology has shown higher rates of myocardial fibrosis in long-term endurance athletes compared to recreational runners.

Warning Signs Athletes Shouldn't Ignore

One of the challenges with myocardial fibrosis is that it develops silently. The body, however, does give subtle hints. "Not every ache, tired spell, or dip in performance is just 'part of the training'. Sometimes these are red flags your heart is sending you," Dr Kenchappa stresses.

Key warning signs include:

• Unusual chest discomfort
• Palpitations
• A sudden drop in performance despite consistent training
• Easy fatigue or prolonged recovery periods
• Breathlessness disproportionate to the activity

If ignored, these symptoms may progress into more serious conditions like arrhythmias or even heart failure. Early medical intervention can help detect and manage risks before permanent damage occurs.

Photo Credit: Pexels

How Much Running Is Too Much?

The big question for runners is where to draw the line. International guidelines, including those from the World Health Organization (WHO), recommend 150-300 minutes of moderate aerobic activity per week or up to 150 minutes of vigorous endurance activity.

For practical context, Dr Kenchappa advises young runners: "Do not exceed 60-70 kilometres per week on a regular basis. This volume allows you to reap the cardiovascular benefits of running without overburdening the heart."

Structured training can further minimize risks. Interval runs, cross-training with activities like swimming or cycling, and designating rest days are effective ways to prevent repetitive strain on the heart.

Hydration and maintaining electrolyte balance are also critical. "Dehydration and imbalance in sodium or potassium levels increase stress on the heart during endurance activity. Athletes must consciously replenish fluids and electrolytes during training," Dr Kenchappa notes.

The Role Of Regular Heart Check-Ups

Even the fittest-looking athletes may harbour hidden heart risks. This is why preventive screenings are important. Basic tests such as ECG, echocardiograms, and treadmill tests can reveal early changes in heart function.

According to Dr Kenchappa: "Routine cardiac check-ups are essential for young athletes, especially those involved in endurance sports. Early detection of fibrosis or abnormal heart rhythms can help prevent future complications and ensure safe training."

Striking The Right Balance

The key takeaway is not to discourage running, but to highlight the importance of balance. Running remains one of the most effective ways to keep the heart healthy. But like any form of exercise, moderation, rest, and mindful training are essential to protect long-term heart function.

Dr Kenchappa emphasizes: "Running is a powerful tool to build stamina, strengthen the heart, and clear the mind. But overdoing it and neglecting recovery is counterproductive. Respect your body, listen to warning signs, and train smart, that's how athletes can sustain their passion without harming their heart."

As India embraces endurance sports with enthusiasm, experts caution against the "more is better" approach. Myocardial fibrosis may be rare, but its risks are real for those who push their limits without balance. For young athletes and recreational runners alike, the message is simple: consistency and moderation build lifelong health, while excess can silently scar the heart.

Disclaimer: This content including advice provides generic information only. It is in no way a substitute for a qualified medical opinion. Always consult a specialist or your own doctor for more information. NDTV does not claim responsibility for this information.

References:

Journal of the American College of Cardiology: Endurance Exercise and Myocardial Fibrosis

World Health Organization: Physical Activity Guidelines, 2020