Running is the leisure-time physical activity of choice for many people, despite recent public concern about possible harmful effects of excessive running. Physical activity undoubtedly offers substantial health benefits, but the dose-response relationship between leisure-time running and mortality is unknown. However, a recent JACC study found good news for those dragging their feet to start routine physical activity: even 5-10 minutes of moderate running per day could significantly lower mortality risk.

In a group of 55,137 adults from the Aerobics Center Longitudinal Study, Lee et al. investigated whether leisure-time running is associated with all-cause and cardiovascular disease (CVD) mortality risks, and whether changes in running behaviors may have impacted that relationship. Running or jogging activity during the previous 3 months was assessed at baseline by a medical-history questionnaire, which included questions about duration, distance, frequency, and speed.

At baseline, approximately 24% of adults participated in running; overall, runners were more likely to be men, younger, leaner, smoked less, participated less in other types of physical activities, and had a lower prevalence of chronic diseases and higher cardiorespiratory fitness levels.

During a mean follow-up of 15 years, there were 3,413 all-cause deaths and 1,217 CVD deaths. After adjusting for potential confounders, Dr. Lee and colleagues found that runners had 30% and 45% lower risks of all-cause and cardiovascular mortality, respectively, compared with non-runners. Notably, these associations were consistent regardless of sex, age, body mass index, health conditions, smoking status, and alcohol consumption.

To examine the potential dose-response question, the investigators divided participants into quintiles of running time: <51, 51-80, 81-119, 120-175, and ≥ 176 minutes/week. Runners across all groups of weekly running time had lower risks of all-cause and CVD mortality compared with non-runners—even those who spent less than 1 hour a week in their running shoes. "Since time is one of the strongest barriers to participate in physical activity, this study may motivate more people to start running and continue to run as an attainable health goal for mortality benefits," they said.

Results of the dose-response relationship analysis between of running distance, frequency, amount, and speed were also encouraging.

Framed another way, not running was almost as important as hypertension in regard to mortality risk, the authors noted, as being sloth-like accounted for 16% of all-cause and 25% of cardiovascular mortality. Also, after adjusting for other mortality predictors, life expectancy for non-runners ran out 3 years earlier compared with that for runners. In their analysis of changes in running behavior, Lee et al. also determined that consistency is key in deriving mortality benefit from physical activity. In a subgroup of 20,647 participants who received at least two medical examinations between 1974 and 2002:

• 65% participants remained non-runners
• 14% stopped running
• 13% continued running
• 8% started running

Compared with never-runners (non-runners at both examinations), runners at one or both examinations broke the tape with lower mortality risks, and persistent runners had the most significant mortality benefit (29% and 50% lower risks of all-cause and CVD mortality, respectively).

While recent studies have proposed that excessive endurance sports may potentially induce adverse cardiovascular effects, such as arrhythmias and myocardial damage, Lee et al. found that runners had 45% lower risk of coronary heart disease mortality (hazard ratio [HR] = 0.55; 95% confidence interval [CI] 0.44-0.69) and a 40% lower risk of stroke mortality (HR = 0.60; 95% CI 0.39-0.92), compared with non-runners. Runners left non-runners in the dust in other areas as well: the sudden cardiac death rate for runners was approximately half that seen in non-runners (1.5 vs. 0.7 per 10,000 person-years).

In an accompanying editorial, Wen et al. point out that despite the well-established benefits of physical exercise, a large proportion of the global population remains sedentary. Surveys revealed that more than half of all US adults failed to comply with the evidence-based 2008 Physical Activity Guidelines, which recommend at least 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity aerobic activity per week (or an equivalent combination of both), goals maintained in the 2013 AHA/ACC lifestyle management guideline to reduce cardiovascular risk.

"Setting a standard perceived as being too high could deter many people from even trying," they write. "Instead, establishing goals that can be attained with minimal effort becomes important." As Lee et al. report in their study, just 5-10 minutes per day—far below the guideline recommendations—could add 3 years of life expectancy and other significant benefits.

"Warn patients that inactivity can lead to a 25% increase in heart disease, and a 45% increase in cardiovascular disease mortality," Dr. Wen and colleagues advise. "While most patients are aware of the benefits of exercise, it is up to [doctors] to move them from wishful thinking to a practical reality, and move them from contemplation to the action phase." And while we’re on the subject of doctors moving,  doctors also need to "walk the talk"—spending at least 15 minutes a day in dedicated exercise themselves, while also advocating to build a culture of physical activity around them. "We do not need to be an athlete to exercise," they concluded. "It should be part of all of our daily routines."

Lee D-C, Pate RR, Lavie CJ, et al. J Am Coll Cardiol. 2014;64:472-81.
Wen CP, Wai JPM, Tsai MK, Chen CH. J Am Coll Cardiol. 2014;64:482-4.