(Reuters Health) - Staying active, even only slightly, confers major longevity benefits, researchers say. 
 
 During many years of follow-up, people who did less than the minimum recommended amount of physical activity still had a considerable decrease in risk of death compared to people who did no activity at all, in a new analysis of six studies. 
 
 “Our findings support the 2008 Physical Activity Guidelines for Americans, which recommend a minimum of 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity activity per week for “substantial” health benefit, and suggest “additional” benefit with more than double the exercise minimum,” said lead author Hannah Arem of the National Cancer Institute in Bethesda, Maryland. 
 
 Researchers pooled data on more than 660,000 men and women in the U.S. and Europe from previous studies. Half the studies had tracked participants for more than 14 years. Overall, 116,686 deaths were recorded. 
 
 Based on self-reports of physical activity, people who did less than the recommended minimum of activity were still 20 percent less likely to die during the studies than people who were not active at all. 
 
 Mortality risk was 31 percent lower for people who did one to two times the recommended minimum, and 37 percent lower for those who did two to three times the recommended minimum activity. 
 
 Mortality risk seemed to level off at three to five times the recommended minimum amount of exercise, which is equivalent to a weekly minimum of walking 7 hours or running 2 hours 15 minutes, Arem told Reuters Health by email. 
 
 But there was no evidence that doing even 10 times the minimum recommended amount would do any harm, the authors write in JAMA Internal Medicine. The results were similar whether the research team analyzed deaths from any cause, or deaths specifically from cardiovascular disease or cancer. 
 
 “While we adjusted for known mortality risk factors like body mass index and smoking, we were not able to adjust for diet in this study as we did not have information available in all cohorts,” she said. “However, in previous analyses in these cohorts where information on diet was available, the associations between physical activity and mortality persisted even after they were adjusted for diet.” 
 
 The new results largely reinforce existing guidelines, which already state that some activity is better than no activity, according to Todd M. Manini of the University of Florida in Gainesville. 
 
 Manini wrote an editorial accompanying the new findings. 
 
 “Getting just a little bit above doing nothing, there was a 20 percent reduction in mortality,” he told Reuters Health by phone. “That was the biggest shift going from one category to another.” 
 
 Just one hour of brisk walking or 30 minutes of jogging or biking per week is enough to move into that first category and out of the “inactive” group, he noted. Doing more than the recommended amount didn’t seem to decrease mortality risk much further, but may have many other health benefits beyond just decreasing the risk of death, Manini said. 
 
 Volume of activity, rather than intensity, drove longevity benefit in the new findings, Arem said. 
 
 A study of middle-aged and older Australians published in the same issue of JAMA Internal Medicine found that vigorous activity was more strongly linked to a decreased risk of death than moderate intensity activity. 
 
 “Future research is needed to determine whether associations between physical activity and mortality differ by specific activities,” Arem said. 
 
 SOURCE: bit.ly/IZGqPC JAMA Internal Medicine, online April 6, 2015. ||||| Doing a few hours of exercise every week will probably help you live longer, but doing a whole lot more exercise doesn't provide much extra benefit, according to a new study on physical activity and longevity. 
 
 Still, doing as much as 10 times the recommended amount of exercise was not linked with an increased risk of dying during the study period. That's good news for marathon runners and triathletes who may have been concerned about the long-term health effects of such high levels of activity. 
 
 In the study, researchers analyzed information from more than 660,000 people ages 21 to 98 in the United States and Sweden who answered questions about how much time they spent doing physical activity, including walking, running, swimming and bicycling. (These questions were asked as part of earlier research conducted in the 1990s and 2000s.) 
 
 People who got some exercise, but not enough to meet the physical activity recommendations were still 20 percent less likely to die over a 14-year period than those who did not do any physical activity. (The recommendations say to do 150 minutes of moderate activity per week or 75 minutes of vigorous activity per week.) 
 
 People who engaged in the recommended level of physical activity saw even more benefit: They were 31 percent less likely to die during the study period, compared with those who did not engage in any physical activity. [7 Common Exercise Errors and How to Fix Them] 
 
 But doing a lot more activity than that did not provide much added benefit. The maximum benefit was seen among people who engaged in three to five times the recommended levels of physical activity; they were 39 percent less likely to die over the study period than people who did no exercise. Engaging in more exercise than this was not linked with any additional benefit. 
 
 Although some earlier studies suggested that people who practice extreme endurance training have an increased risk of heart problems, the new study found no link between very high levels of physical activity (10 or more times the recommended level) and an increased risk of death. 
 
 "These findings are informative for individuals at both ends of the physical activity spectrum: They provide important evidence to inactive individuals by showing that modest amounts of activity provide substantial benefit for postponing mortality while reassuring very active individuals of no exercise-associated increase in mortality risk," the researchers, from the National Cancer Institute, wrote in the April 6 issue of the journal JAMA Internal Medicine. 
 
 In an editorial accompanying the study, Todd Manini, of the University of Florida's Department of Aging and Geriatric Research, pointed out that the people most likely to benefit from increasing the amount of exercise they do are those who do not currently do any. 
 
 "A lot of the mortality reductions were seen in people only one step away from doing no leisure-time physical activity," Manini said, referring to the group that did some physical activity, but not enough to meet the recommendations. 
 
 Doctors should target this group with exercise counseling, Manini said. "Physicians who seek out the segment of the population that performs no leisure-time physical activity could receive the most payback in their patient's health." 
 
 The new study relied on reports of physical activity at one point in time, and it's possible that people changed their levels of physical activity over the study period, the researchers said. 
 
 In addition, the study looked at the time spent engaged in physical activity, but did not focus on the intensity of that activity. That is, it did not directly compare those who engaged in moderate activity versus those who engaged in vigorous activity. But the study did find that people who met the recommended level of physical activity — either through moderate or vigorous activity levels — had a reduced risk of death. 
 
 In a separate study, also published today in JAMA Internal Medicine, researchers in Australia found that people who engaged in vigorous activity (such as jogging or aerobics) were 9 to 13 percent less likely to die over a six-year period than those who engaged in only moderate activity (such as gentle swimming or household chores). 
 
 "Our research indicates that even small amounts of vigorous activity could help reduce your risk of early death," study researcher Klaus Gebel, of James Cook University's Centre for Chronic Disease Prevention in Australia, said in a statement. 
 
 But people with medical conditions, older adults or those who have not previously engaged in vigorous activity should speak with their doctors before beginning an exercise program, Gebel said. 
 
 Follow Rachael Rettner @RachaelRettner. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science. ||||| Importance The 2008 Physical Activity Guidelines for Americans recommended a minimum of 75 vigorous-intensity or 150 moderate-intensity minutes per week (7.5 metabolic-equivalent hours per week) of aerobic activity for substantial health benefit and suggested additional benefits by doing more than double this amount. However, the upper limit of longevity benefit or possible harm with more physical activity is unclear. 
 
 Objective To quantify the dose-response association between leisure time physical activity and mortality and define the upper limit of benefit or harm associated with increased levels of physical activity. 
 
 Design, Setting, and Participants We pooled data from 6 studies in the National Cancer Institute Cohort Consortium (baseline 1992-2003). Population-based prospective cohorts in the United States and Europe with self-reported physical activity were analyzed in 2014. A total of 661 137 men and women (median age, 62 years; range, 21-98 years) and 116 686 deaths were included. We used Cox proportional hazards regression with cohort stratification to generate multivariable-adjusted hazard ratios (HRs) and 95% CIs. Median follow-up time was 14.2 years. 
 
 Exposures Leisure time moderate- to vigorous-intensity physical activity. 
 
 Main Outcomes and Measures The upper limit of mortality benefit from high levels of leisure time physical activity. 
 
 Results Compared with individuals reporting no leisure time physical activity, we observed a 20% lower mortality risk among those performing less than the recommended minimum of 7.5 metabolic-equivalent hours per week (HR, 0.80 [95% CI, 0.78-0.82]), a 31% lower risk at 1 to 2 times the recommended minimum (HR, 0.69 [95% CI, 0.67-0.70]), and a 37% lower risk at 2 to 3 times the minimum (HR, 0.63 [95% CI, 0.62-0.65]). An upper threshold for mortality benefit occurred at 3 to 5 times the physical activity recommendation (HR, 0.61 [95% CI, 0.59-0.62]); however, compared with the recommended minimum, the additional benefit was modest (31% vs 39%). There was no evidence of harm at 10 or more times the recommended minimum (HR, 0.69 [95% CI, 0.59-0.78]). A similar dose-response relationship was observed for mortality due to cardiovascular disease and to cancer. 
 
 Conclusions and Relevance Meeting the 2008 Physical Activity Guidelines for Americans minimum by either moderate- or vigorous-intensity activities was associated with nearly the maximum longevity benefit. We observed a benefit threshold at approximately 3 to 5 times the recommended leisure time physical activity minimum and no excess risk at 10 or more times the minimum. In regard to mortality, health care professionals should encourage inactive adults to perform leisure time physical activity and do not need to discourage adults who already participate in high-activity levels.
– If you've given up physical activity because you don't have the time or inclination to achieve recommended weekly exercise levels, strap on your walking shoes: A new study in JAMA Internal Medicine indicates that something's better than nothing in terms of increasing longevity. Scientists from the National Cancer Institute looked back at six studies and found individuals who followed the 2008 Physical Activity Guidelines of 150 minutes per week of moderate-intensity aerobic exercise—or 75 minutes of vigorous-intensity workouts—achieved "substantial" benefit, while those who doubled that baseline reaped "additional" benefit, Reuters reports. But researchers also made the significant find that those who exercised even a bit were 20% less likely to die than those who hunkered down on the couch with their remotes and did nothing. Scientists looked at 661,137 men and women (ages 21 to 98) who provided their own reports on their physical activity levels; 116,686 deaths were reported among these subjects, per the study. Those who met the guidelines saw a 31% increase in longevity over their nonactive counterparts, while participants who did three to five times the recommended levels did 39% better than the sedentary, LiveScience reports. Interestingly, exercise beyond that didn't seem to confer further benefit, but it also didn't appear to be harmful: Researchers found no link between those who worked out up to 10 times or more than the guidelines and increased death rate. A University of Florida aging specialist writes in the study's accompanying editorial that "physicians who seek out the segment of the population that performs no leisure-time physical activity could receive the most payback in their patient's health" if they recommend even a small amount of exercise. (Even a lunchtime stroll may make you feel better.)