COPENHAGEN, DENMARK — Even just a little jogging done at a very easy pace goes a long way toward increasing longevity, according to a new analysis. The results also suggest there is a limit to the benefit and that too much running—done more frequently, for longer periods, or at a greater intensity—was not associated with any additional mortality benefits compared with sedentary nonrunners.
"The U-shaped association suggests the existence of an upper limit for exercise dosing that is optimal for health benefits," write Dr Peter Schnohr (Frederiksberg Hospital, Copenhagen, Denmark) and colleagues February 2, 2015 in the Journal of the American College of Cardiology.
The researchers add that accumulating data show that ideal activity patterns for promoting long-term cardiovascular health and increasing life expectancy might differ from the high-intensity, high-volume endurance training programs needed to develop peak performance and maximal cardiorespiratory fitness.
Copenhagen City Heart Study
The results are based on data from 1098 healthy joggers and 3950 healthy nonjoggers in the Copenhagen City Heart Study. Within the study group, 9% were 50 years of age or older. Overall, there were 28 deaths among joggers and 128 deaths among the sedentary participants.
Light jogging was defined as a slow or average pace (approximately 5 mph), three or fewer times per week, for less than 2.5 hours total per week. Moderate jogging was defined as a slow or average pace, three or fewer times per week, but for 2.5 hours or more per week. (Moderate jogging was also defined as a faster pace, more than three times per week, or 4 hours or less per week.) Strenuous jogging was defined as running at a fast pace (>7 mph), more than 3 times per week, and 4 hours total per week.
Researchers published the association between duration, frequency, and pace of running with all-cause mortality:
Joggers who ran 1 to 2.4 hours per week had the lowest risk of mortality, with a significant 71% lower risk of death than sedentary nonjoggers.
Individuals who ran less than 1 hour per week had a significantly 53% lower risk of all-cause mortality. In contrast, compared with the sedentary group, those who ran 2.5 to 4 hours per week or more than 4 hours per week did not have a lower risk of mortality.
Regarding frequency, the optimal dose of jogging was two to three times per week. These joggers had a significantly 68% lower risk of death compared with the healthy sedentary group. Even those who ran once per week had a significantly lower risk of death compared with nonjoggers (hazard ratio 0.29; 95% CI, 0.12–0.72); those who jogged three or more times per week did not.
In terms of pace, slow-paced joggers had a significantly 49% lower risk of death compared with sedentary nonjoggers. The fastest runners—those who covered more than 7 mph—had the same mortality risk as sedentary nonjoggers.
"The lowest mortality was among light joggers in relation to pace, quantity, and frequency of jogging," according to Schnohr and colleagues. "Moderate joggers had a significantly higher mortality rate compared with light joggers, but it was still lower than that of sedentary nonjoggers, whereas strenuous joggers had a mortality rate that was not statistically different from that of sedentary nonjoggers."
Accumulating Evidence Against Doing Too Much
This is not the first study to show that more exercise isn't necessarily better in terms of health and longevity.
In 2012, Dr Carl Lavie (Ochsner Health System, New Orleans, LA) and Dr Duck-chul Lee (Iowa State University, Ames) published data from a retrospective analysis of more than 52 000 men and women participating in the Aerobics Center Longitudinal Study (ACLS). The study showed that the benefits of running are best accumulated in shorter distances, specifically at less than 20 miles per week. At longer distances, the researchers observed a U-shape relationship between all-cause mortality and running, with longer weekly distances trending in the wrong direction toward less mortality benefit.
Two years later, the same researchers published another study that showed just 5 to 10 minutes of daily running, performed even at very slow speeds, significantly lowered an individual's risk of all-cause and cardiovascular mortality. Lee, Lavie, and colleagues reported that just this small amount of running was associated with a 30% reduction in all-cause mortality, a 45% reduction in cardiovascular disease, and could add 3 years of life expectancy. The study involved 55 137 adults followed for 15 years at the Cooper Clinic in Dallas, TX.
Beyond these studies, epidemiological and observational studies have shown a significant association between high-intensity aerobic exercise and an increased risk of atrial fibrillation.
In the US, physical-activity guidelines call for 150 minutes or more per week of moderate-intensity or 75 minutes per week of vigorous-intensity aerobic physical activity.
Is More Exercise Truly Harmful?
To heartwire , Lavie said that from a health standpoint, the maximal health benefits of exercise are likely obtained at low doses. This study, as well as the other analyses, appears to support the idea that when it comes to overall health, particularly living longer, running more frequently, for longer durations, or more intensely, is not necessarily better. The jury is still out, however, when it comes to concluding that more exercise is harmful to health, he said. Their data, for example, did not suggest harm among individuals in the highest quintile of running volume.
Lavie said there are legitimate reasons why people might want to run more, including mental health, racing performance, weight loss, or even just to be able to eat more, but these individuals are doing so for reasons not related to longevity or health. And although high-dose exercise might be associated with some risk, the overall risk appears to be small, so it's important not to scare athletes such as marathon runners or triathletes. That said, he does not believe running 52 marathons or six ultra-long-distance Ironman triathlons annually is healthy long term.
For doctors and patients, the take-home message is that extreme exercise is not needed for health, Lavie told heart wire.
Along with Lee and Dr Rajesh Vedanthan (Icahn School of Medicine at Mount Sinai, New York, NY), Lavie wrote an accompanying editorial to the Copenhagen analysis, noting that the study had low statistical power for higher doses of running. In the study, just 47 joggers ran more than 4 hours per week and only 80 joggers ran more than three times per week. In fact, the mortality reduction was moving in the right direction such that had the study had more statistical power, researchers might have shown a benefit with higher running doses or frequency.
The editorialists point out that the usual caveats apply to retrospective analyses. For example, the sedentary nonjoggers were more obese and older and had higher rates of diabetes and hypertension than the active participants. Although the researchers adjusted for these baseline variables, it is possible that unmeasured confounding variables might have influenced the results, they state.
The authors and editorialists have no relevant financial relationships.
Heartwire from Medscape © 2015 Medscape, LLC
Cite this: Short, Easy—Not Strenuous—Jogging Gives Biggest Survival Gain: Analysis - Medscape - Feb 02, 2015.