How to protect your heart: Cardiologist shares 3 tips to prevent fatigue during a marathon

How to protect your heart during marathons? Find tips on screening, fatigue prevention, and recovery strategies from a leading cardiologist.

Marathon running is not only a test of heart strength but also of the strength of the mind. Thousands of runners will be tested to the limit in challenging climatic conditions at the Tata Mumbai Marathon (TMM), scheduled for Sunday, January 18, 2026, in Mumbai. Although the physiological impact on the runner's heart and energy systems may be a strong motivator, a well-constructed strategy for safety and performance is necessary.

How to protect your heart and prevent fatigue during a marathon?

To protect your heart and prevent fatigue during a marathon, consider these key tips:

Make cardiovascular safety a priority

At 42.2 kilometres, the heart endures significant stress. To protect it:

• Pre-race screening: "Runners and athletes in general, particularly those older than 35 years with a family history of heart disease, are to undergo an ECG and a stress test before starting any training cycle," says Dr Vijay D’silva, Cardiologist, White Lotus International Hospital, tells Health Shots. This helps detect underlying structural problems or arrhythmias that may be triggered by exertion.
• Awareness of cardiac drift in the human body: "When body temperature rises, the heart rate also increases, though the pace remains similar; measured heart rate zones, but not split times," says the cardiologist. If the heart rate enters the red zone prematurely, slow down to prevent overstraining.
• Viral recovery: Do not run a marathon or engage in intense training in the near future after a viral illness. "Post-viral myocarditis (inflammation of the heart muscle) is a cause of sudden cardiac events in endurance athletes," shares the expert.

2. Strategic fatigue prevention

The causes of fatigue in a marathon are most often either glycogen depletion (the wall) or electrolyte imbalance.

• Periodized fueling: It is just as important to train the gut as it is to train the legs. "Eating 30-60 grams of carbohydrates per hour will keep blood glucose at normal levels and prevent central nervous system fatigue," says the doctor.
• Precision hydration: Dehydration thickens the blood, increasing cardiac workload, whereas overhydration may lead to hyponatremia. Hydrate by drinking water and replenishing essential electrolytes (sodium, potassium, and magnesium).
• The 10% rule: Weekly increases in the mileage ratio must not exceed 10%. "This enables the heart and muscles to adjust and become stronger without falling into chronic fatigue," says Dr D’silva.

3. Recovery as protection

The heart is like any other muscle, requiring time to mend. Sleep and anti-inflammatory nutrition should be prioritised during post-race recovery. "A gradual reverse taper back to high-intensity training mustn't be done too soon, as this may lead to persistent fatigue and increased troponin levels, indicators of cardiac stress," says Dr D’silva. A responsible approach of pacing and listening to the body's intuition can help runners training for races achieve their personal bests without compromising their long-term cardiovascular health.