Taking brisk, half-hour walks just six times a month appeared to cut the risk of premature death by 44 percent among twins in a study researchers say is the first to separate the influences of heredity and exercise on longevity.
The study tracked almost 16,000 healthy men and women in a national registry of twins in Finland for an average of 19 years. The authors, led by Dr. Urho M. Kujala of the University of Helsinki, reported their findings in Wednesday's issue of The Journal of the American Medical Association.The researchers found that even occasional exercisers - those who did less than the equivalent of six brisk, half-hour walks a month - were 30 percent less likely to die than their sedentary twins.
Vigorous exercisers - those who did at least the equivalent of six brisk walks or jogs lasting 30 minutes each month - were 44 percent less likely to die.
"Even if you have bad genes, this study strongly suggests that increasing physical activity can help you live longer," said exercise physiologist Steve Farrell, associate director of the Cooper Institute for Aerobics Research in Dallas. He was not involved in the study.
The purpose of the study was to clarify the relationship between those factors influencing how long people live that can be modified and those that cannot.
The importance of family history - a locked-in trait - has gained attention in recent years with the identification of specific genes that make people susceptible to such illnesses as heart disease and cancer. But much research also makes clear the importance of exercise in lowering the risk of early death and disease.
The researchers took into account differences in smoking habits.
At the study's conclusion in 1994, there were 434 sets of twins in which one sibling had died of natural causes and the other survived. In 173 of those 434 sets, the twins had exercised at different levels.