By Katherine Harmon
(Click here for the original article and podcast)

A little exercise each week can lead to big gains in life expectancy. And that's true regardless of your current weight, according to a new review study that included more than 650,000 people. 

The World Health Organization recommends two-and-a-half to five hours of brisk walking per week, or less time spent at a more vigorous activity. People who got the full recommended amount of exercise saw an average 3.4-year gain in life expectancy. People who got half as much exercise still lived an average 1.8 years longer. The findings are in the journal PLoS Medicine. [Steven C. Moore et al., Leisure Time Physical Activity of Moderate to Vigorous Intensity and Mortality: A large pooled cohort analysis]

In fact, exercise was a bigger factor than body weight in many cases. People who were normal weight but were inactive actually lived an average of 3.1 fewer years than obese people who kept up high levels of activity.  

Finding time to exercise can be tough. Maybe look at it this way. There are almost 9,000 hours in a year. Five hours a week is 260 hours a year--to get an extra 30,000 hours of life. Do the math. While you take a walk.

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  • Take The Stairs

    In 2008, a small Swiss study found that sedentary people who switched from taking escalators and elevators to taking the stairs <a href="http://news.bbc.co.uk/2/hi/7591311.stm" target="_hplink">cut their risk of dying prematurely by 15 percent</a>. "This suggests that stair climbing can have major public health implications," lead researcher Dr. Philippe Meyer, told the BBC. An earlier look at data from the Harvard Alumni Health Study also found that climbing 35 or more flights of stairs a week significantly <a href="http://aje.oxfordjournals.org/content/151/3/293.short" target="_hplink">increased longevity</a> when compared to people who climbed fewer than 10 stories a week. <em>Flickr photo by <a href="http://www.flickr.com/photos/mariachily/3381125472/" target="_hplink">mariachily</a></em>

  • Bike... Faster!

    <a href="http://www.huffingtonpost.com/2012/04/17/bicycle-bike-commuting-tips_n_1427869.html" target="_hplink">Biking to work</a> is a great way to squeeze exercise into your day, spend some time outside and even save on gas money. But a leisurely ride, while it might leave you less sweaty upon arrival at the office, won't do as much for your lifespan as if you really ride it out. A study of <a href="http://www.sciencedaily.com/releases/2011/08/110829070507.htm" target="_hplink">Copenhagen cyclists</a> found that men who pedaled the fastest lived more than five years longer than slower cycling men, and the fastest women cyclists lived almost four years longer. <em>Flickr photo by <a href="http://www.flickr.com/photos/8136496@N05/3801963043/" target="_hplink">terren in Virginia</a></em>

  • Take A Swim

    A 2009 analysis of data from the Aerobics Center Longitudinal Study found that men who swam regularly had about a 50 percent <a href="http://www.reuters.com/article/2009/02/02/idUS159078+02-Feb-2009+PRN20090202" target="_hplink">smaller risk of dying</a> than sedentary men -- but swimmers also had a lower mortality rate than <a href="http://www.prevention.com/fitness/fitness-tips/swim-longer-life" target="_hplink">men who walked and ran</a> for their exercise. <em>Flickr photo by <a href="http://www.flickr.com/photos/west_point/4752428605/" target="_hplink">West Point Public Affairs</a></em>

  • Pick Up The (Walking) Pace

    A <a href="http://jama.ama-assn.org/content/305/1/50.full" target="_hplink">2011 study</a> found that people who naturally walk at a pace of one meter per second, about 2.25 mph, or faster, <a href="http://www.msnbc.msn.com/id/40914372/ns/health-fitness/t/walk-faster-you-just-might-live-longer/#.T6f8JZ9Ytdo" target="_hplink">lived longer than their slower peers</a>. But walking pace might be more of an <em>indicator</em> of longevity rather than a way to increase it, the study's author cautioned. "Your body chooses the walking speed that is best for you, and that is your speed, your health indicator," lead researcher Dr. Stephanie Studenski told MyHealthNewsDaily. "Going out and walking faster does not necessarily mean you will suddenly live longer," she said. <em>Flickr photo by <a href="http://www.flickr.com/photos/29143375@N05/4012888936/" target="_hplink">Justin Scott Campbell</a></em>

  • Work Out For 15 Minutes A Day

    Some think to get the full benefit of a good workout, you need to be sweating for a full 30 minutes -- or longer. But with so many people struggling to find a spare 30 minutes, researchers have begun to investigate if a shorter sweat session could be just as good. A 2011 study found when compared to sedentary people, <a href="http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(11)60749-6/abstract" target="_hplink">15 minutes of daily activity</a>, like brisk walking, <a href="http://www.reuters.com/article/2011/08/15/us-exercise-taiwan-idUSTRE77E69L20110815 " target="_hplink">added three years to life expectancy</a>, according to Reuters. <em>Flickr photo by <a href="http://www.flickr.com/photos/lululemonathletica/3616976712/" target="_hplink">lululemon athletica</a></em>

  • Kick It Up A Notch

    Walking faster, cycling harder -- there's an underlying theme to many of the benefits of exercise: <a href="http://www.ncbi.nlm.nih.gov/pubmed/7707624" target="_hplink">intensity</a>. Overall, <a href="http://jama.ama-assn.org/content/273/15/1179.short" target="_hplink">vigorous activities</a> seem to have more life-lengthening powers than nonvigorous activities, according to a 1995 study. In fact, <a href="http://archinte.ama-assn.org/cgi/content/full/165/20/2355" target="_hplink">intense exercise may double the years added</a> by moderate exercise, according to a 2005 study. Five days a week of walking for 30 minutes led to 1.3 to 1.5 additional years, <em>The Washington Post</em> reported, but intense exercise, like running half an hour five days a week, resulted in <a href="http://www.washingtonpost.com/wp-dyn/content/article/2005/11/14/AR2005111401051.html" target="_hplink">3.5 to 3.7 extra years</a>. <em>Flickr photo by <a href="http://www.flickr.com/photos/frankjuarez/2334732010/" target="_hplink">frankjuarez</a></em>

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