Marathon running & mortality: Endurance training improves fitness & possibly reduces average long term mortality. However, risk of dying during running itself is marginally higher than average. Of course, marathon running us a rare cause of death. Problems during running:
- Heart attack: increased shear stress of blood during endurance training can rupture coronary atherosclerotic plaques causing thrombosis & MI. Risk in untrained runners, smokers. Train gradually & stop smoking to prevent.
- Hypertrophic cardiomyopathy: commonly implicated in sudden death during competitive sports. Prevalence of HCM in community is underestimated though not the variants leading to high mortality. Routine echo not advised unless family h/o sudden death or dizziness during runs.
- Hyperthermia: Every hour of running leads to increase in core body temperature by 1 degree C. Adequate cooling by drinking water/dousing oneself with water can prevent hyperthermia related problems.
- Dehydration/ Hyponatremia: loss of fluid & electrolytes can cause cardiac arrest, if inadequately/inappropriately replaced. Mere free water intake during long distance running can lead to electrolyte imbalance esp low sodium. Electrolyte solutions/tablets advised.