Exercise provides a remarkable variety of health benefits, which range from strengthening bones to positive effects on mood and helping to prevent chronic illnesses such as diabetes and heart disease. Research dating back to the late 1980s has consistently shown that aerobic fitness may help extend lives. Yet a few studies on athletes examining whether habitual vigorous exercise might harm the heart made some experts wonder how hard people ought to push when exercising (see here and here).
Do cardiorespiratory fitness levels affect longevity?
A retrospective study in JAMA attempts to answer this question. The study explores the association between long-term mortality and various levels of cardiorespiratory fitness (CRF). CRF is a measure of how well your heart and lungs pump blood and oxygen throughout the body during prolonged bouts of exercise. The more fit you are, the higher your level of CRF. Regular exercise, and vigorous exercise, can both boost CRF.

The researchers looked at over 122,000 patients at a large academic medical center who underwent exercise testing on a treadmill, an objective measure of CRF. While the average age was 53, participants ranged in age from 18 to over 80. Similar to findings of previous studies, being fit was associated with living longer. This held true at any age. The researchers also saw a relationship between CRF and survival rates: the higher the level of fitness, the higher the survival rate. This was especially notable in older people and people with high blood pressure. And the survival benefit continued to climb with no upper limit.

What does this mean for all of us?
Unless there is a clear medical contraindication, we should all strive to achieve and maintain high levels of fitness. Current guidelines recommend 150 to 300 minutes per week of moderate aerobic activity (walking, running, swimming, biking), or 75 minutes of vigorous activity, or a mix of both. Twice-weekly resistance training to strengthen muscles is also recommended. Unfortunately, only about one in five adults and teens gets enough exercise to maintain good health.