When it comes to jogging, more may not be better for long-term heart health, according to a study published in the Feb. 10 issue of the Journal of the American College of Cardiology. Researchers returning to the Copenhagen City Heart Study cohort found that while light or moderate jogging two-to-three times per week had lowered mortality risks, strenuous joggers had risks similar to sedentary individuals.
Peter Schnohr, MD, DMSc, from Frederiksberg Hospital in Copenhagen, Denmark, and colleagues used surveys to determine individual level of activity. Starting in 2001, the research team followed 1,098 joggers of varying levels and 413 non-joggers, with no history of coronary heart disease, stroke or cancer. They defined the levels of jogging as light, moderate and strenuous. Light jogging had a slow to average pace around 5 miles an hour, less than 2.5 hours of jogging per week and a frequency of up to three times a week. Strenuous joggers had a fast pace of more than 7 miles per hour and jogged 2.5 hours or more more than three times a week.
They found that jogging one to 2.4 hours per week reduced mortality risk by approximatly 70 percent when compared with non-joggers (hazard ratio: 0.29). Increased jogging, from 2.5 to four hours a week reduced mortality risk to a lesser degree, approximately 35 percent (0.65). Jogging once a week also appeared to have the most influence on reducing risk, an about 70 percent reduction (0.29) with jogging two-to-three times per week reducing comparative risk by about 68 percent (0.32). Jogging more than three times a week, they noted, had a mortality risk that was not statistically different from those who were sedentary.
Moderate pace had the lowest mortality rate at 38 percent, followed by slow pace at 51 percent. Meanwhile, fast-paced joggers had a similar mortality rate as non-joggers (0.94).
As a result, Schnohr et al suggested that for optimal longevity, jogging one to 2.4 hours per week, slow to average pacing, and no more than three running days per week was key, calling the goal “practical, achievable and sustainable.”
They noted that evidence from this and other studies suggests that promoting ideal long-term cardiovascular health and life expectancy “may differ from the high-intensity, high-volume endurance training regimens used for developing peak cardiac performance and maximum cardiorespiratory fitness.”
A debate continues, however, amongst some over the benefit of higher levels of activity. An editorial by Duck-chul Lee, PhD, of the College of Human Sciences at Iowa State University in Ames, Iowa, and colleagues noted among runners, more vigorous training remained beneficial for lowering mortality risks over non-runners. They also noted that by restricting their purview to jogging and a relatively small population, Schnohr et al may not have a full picture of the benefit-risk behind other forms of exercise.
Lee et al wrote that Schnohr et al “adds to the current body of evidence on the dose-responsive relationship between running and mortality. However further exploration is clearly warranted regarding whether there is an optimal amount of running for mortality benefits, especially for cardiovascular and CHD mortality.”