As a regular runner I am very interested in the effects of running on lifespan. Intuitively one would expect those who engage in regular vigorous aerobic exercise would have longer lifespans and less disease than those who don’t.
There is, however ,some literature to suggest long duration endurance training may have deleterious effects on the heart. This line of thought adds some controversy to the very large body of evidence that exercise is beneficial.
A new very well performed long duration study of regular joggers enrolled in the Copenhagen City Heart Study sheds some very clear light on the effect of long term jogging on health and survival.
This study followed 19,329 people from when it began in 1976. At that time, the ages of the participants were between 20 and 92 years old. The subjects were followed up until death or June of 2011, whichever came first
Of the study population a total of 1878 (1116 men and 762 women) considered themselves joggers during at least one of four follow up visits. Those who were joggers were questioned about the amount and intensity of jogging that they did.
Overall during the 35 years of follow up, they registered 122 deaths among the joggers and 10,158 among the non joggers. This translated to an age adjusted mortality of 44% less for the joggers as a whole, which was highly significant. It was significant for both sexes and for ages greater or less than 50. Jogging added 6.2 years of extra life for men and 5.6 years for women.
Jogging was consistent among the joggers. The average amount of jogging was 10 years and the likelihood a person was still jogging from the first to fourth interview was 64%.
The authors were particularly interested in seeing if jogging faster, longer or more frequently had any additional benefit or detriment to the participants.
The amount of time jogging affected mortality. Those jogging < 1 hour per week were 32% less likely to die, those jogging 1-2.4 hours were 42% less likely, for 2.5-4 hours, 21% less likely, and for those jogging > 4 hours, a 14% lower mortality rate.
Also affecting mortality was pace/intensity. Slow joggers (5 mph) had a 63% mortality reduction and average joggers (6 mph) had a 47% reduction in mortality. Fast pace (>7 mph) joggers however had a 22% higher mortality, though the confidence interval was very wide (0.49-3.04).
Jogging frequency was a another variable looked at. Those jogging up to and including 1-3 times per week had a 60% reduced mortality, but those jogging more than three times per week had a 24% increased mortality though the confidence interval was again very wide (.51-3.02)
Taken together these findings show that regular slow to average paced jogging 1 to 3 times per week and from 1-2.5 hours had a very potent reduction in mortality compared to not jogging. There may be a U-shaped curve, however, with no statistical benefit to jogging more frequently and at faster paces.