Marathons v. Peak Fitness

• Every year a handful of runners die while competing in a marathon; most recently, a healthy 30-year-old running the London Marathon to raise money for an organization that helps prevent suicides collapsed about a mile short of the finish line and died
• Heatstroke can be a factor in marathon deaths, as can hyponatremia -- low sodium levels in the blood often caused by drinking too much water during exercise -- but in the vast majority of cases, people die during marathons because of a heart attack
• Marathon running puts an extraordinary stress on your heart; research shows the extended vigorous exercise performed during a marathon raises cardiac risk by seven-fold
• The most recent research shows that relatively short bursts of intense exercise such as Peak Fitness—even if done only a total of a few minutes each week—can deliver many of the health and fitness benefits you get from doing hours of conventional cardio exercise, without the potential damage to your heart