Strenuous jogging may do more harm than good

No pain, no gain" is often the phrase used when it comes to exercise. But in relation to jogging, this may not be the case. 

In a new study, researchers found people who engage in strenuous jogging have the same mortality risk as sedentary non-joggers, while light joggers are likely to live the longest.

Less is more when it comes to jogging; researchers found light jogging is best for improving life expectancy.

Researchers at the Frederiksberg Hospital in Copenhagen, Denmark publish their findings in the Journal of the American College of Cardiology.

Numerous studies have associated physical activity with reduced mortality, with some suggesting that just small amounts of exercise can do the job. 

A recent study, for example, claims that a daily 20-minute brisk walk could reduce the risk of early death by 16-30%.

The link between lower levels of exercise and reduced mortality is supported with this latest study, which suggests light jogging is most beneficial for lowering the risk of premature death.

To reach their findings, the researchers analyzed 5,048 healthy individuals who were a part of the Copenhagen City Heart Study. Of these, 1,098 were joggers and 3,950 were sedentary non-joggers.

Over 12 years of follow-up, the researchers tracked participants' frequency of jogging, the number of hours they spent jogging and their jogging pace.

Jogging more than a few times a week at a strenuous pace 'may be harmful'

During the study, there were 28 deaths among joggers and 128 among non-joggers. The team notes that overall, the joggers were younger, had a lower prevalence of diabetes and smoking, and had lower blood pressure and body mass index (BMI).

The researchers found that participants who jogged for 1-2.4 hours a week over no more than 3 days had the lowest mortality, and lower mortality rates were identified among those who jogged at a slow or moderate pace. The highest mortality rates were found in both the fast-paced joggers and sedentary non-joggers.

"The U-shaped association between jogging and mortality suggests there may be an upper limit for exercise dosing that is optimal for health benefits. If your goal is to decrease risk of death and improve life expectancy, jogging a few times a week at a moderate pace is a good strategy. Anything more is not just unnecessary, it may be harmful."

The Physical Activity Guidelines for Americans state that adults should engage in either 2.5 hours of moderate-intensity aerobic activity or 1.25 hours of vigorous-intensity aerobic activity every week.

The researchers note that light jogging in this study represents vigorous exercise, while strenuous jogging represents very vigorous exercise. When performed for decades, this activity level could pose health risks, especially to the cardiovascular system.

In November 2014, another team of researchers  reported on a study suggesting running for 30 minutes at least three times a week may slow the aging process.

References:

1.  Dose of jogging and long-term mortality: the Copenhagen City Heart Study, Peter Schnohr, et al., J Am Coll Cardiol, doi:10.1016/j.jacc.2014.11.023, published February 2015, abstract.
2.  American College of Cardiology news release, accessed 3 February 2015 via EurekAlert.
3.  Additional source: CDC, How much physical activity do adults need?, accessed 3 February 2015.