It's safe for older adults to run marathons, a new study finds.

Researchers at the University of Manitoba in Canada tested marathon participants over age 50 before and after their 26.2-mile run. Using blood tests, ultrasounds and scans up to three months later, they found the runners had temporary heart effects similar to those seen in runners aged 18 to 40.

The effects included a brief increase in blood indicators of heart damage and temporary swelling and weakness in the right side of the heart immediately after the marathon. All of these effects disappeared within a week.

"There was no evidence of permanent heart damage from repeated marathon running in individuals over the age of 50," primary study author Davinder Jassal, an associate professor of medicine, radiology and physiology, said in a university news release.

The study was published online in August in the Journal of Cardiovascular Magnetic Resonance.

Aging populations in Canada and the United States mean there's a growing number of people over age 50 who exercise regularly, the researchers noted. For example, the number of older people taking part in marathons has doubled over the past two decades.

Read More On U.S. News:
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Earlier on Huff/Post50:

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  • Yoga

    Yoga offers a <a href="http://www.huffingtonpost.com/deepak-chopra/yoga-heart-health_b_900621.html" target="_hplink">myriad of wellness benefits:</a> flexibility, balance, centeredness, strength, mindfulness and others. Yoga is a great option for aging bodies, as it promotes working within your own comfort zone. Postures and sequences range from gentle and relaxing to more intensive for advanced yogis.

  • Stretching

    Another way to promote flexibility and overall health is incorporating some simple stretches into your daily routine, be it at home, at the gym or even outdoors. Stretching prevents injury, <a href="http://www.huffingtonpost.com/2011/10/24/yoga-stretching-back-pain_n_1029014.html" target="_hplink">can relieve back pain</a> and boosts energy. Note: It's important to stretch properly to avoid injury. Check out some good <a href="http://www.webmd.com/fitness-exercise/healthtool-basic-stretches" target="_hplink">examples of stretches here</a> and these <a href="http://www.huffingtonpost.com/2011/07/08/stretching-mistakes_n_892444.html#s304603&title=Not_Doing_It" target="_hplink">common stretching mistakes</a>.

  • Biking

    Biking is a great low-impact, cardiovascular workout, not to mention it's a lot of fun. There are a few ways to incorporate biking into your routine. Joy rides in your free time are always a good option -- alone or with a group. You could consider joining a local bike group or riding to nearby destinations instead of taking the car. <a href="http://www.livestrong.com/article/456032-stationary-bikes-and-health-benefits/" target="_hplink">Stationary bikes</a> also have great health benefits. Already a cycler? Here's how to get <a href="http://www.huffingtonpost.com/2011/05/30/6-ways-to-get-more-benefi_n_868670.html#s285033&title=Get_in_tune" target="_hplink">more benefit from your bike ride</a>.

  • Brisk Walks

    One of the most <a href="http://www.mayoclinic.com/health/walking/HQ01612" target="_hplink">beneficial exercises</a> is something humans have been doing for centuries: walking. Simple modifications to your routine, like parking further away and walking the extra distance or taking the stairs instead of the elevator, can really add up to boost your overall health. For an even greater benefit, take brisk walks that get your heart rate up.

  • Pilates

    <a href="http://pilates.about.com/od/whatispilates/a/WhatIsPilates.htm" target="_hplink">Pilates</a> is another low-impact exercise that's ideal for aging bodies. It's similar to yoga but puts more emphasis on gaining control and balance of the body by strengthening the core muscles. Pilates can be done in a class or at home with a video or other guide. <a href="http://www.huffingtonpost.co.uk/paola-bassanese/keep-fit-with-classical-p_b_987756.html" target="_hplink">This piece</a> offers a great run-down of the activity, along with images of some classic pilates stretches and workouts.

  • Tennis

    Tennis is a classic sport, well-loved for being fun and <a href="http://my.clevelandclinic.org/heart/prevention/exercise/tennis.aspx" target="_hplink">great for you</a>. It's a strong aerobic workout and helps keep you agile, especially important as you get older. Tennis is also a very social activity -- great for the body, mind and spirit!

  • Swimming

    Swimming is easy on the body and is also one of the most comprehensive workouts, hitting <a href="http://www.webmd.com/fitness-exercise/guide/fitness-basics-swimming-is-for-everyone" target="_hplink">all the major muscle groups</a>: shoulders, back, abdominals, legs, hips and glutes. If you're getting serious about swimming, it's important to learn proper techniques, but even free-styling in the local pool or outdoors in the summer is a great way to exercise.

  • Dance

    Dancing is one of those activities that doesn't feel like working out, but is an incredible <a href="http://www.livestrong.com/article/91589-fitness-benefits-dance/" target="_hplink">aerobic exercise</a>. It's a good option for those that want more physical activity but don't like the gym or in the winter when it's harder to get outdoors. There are a bunch of styles to choose from: ballroom dancing, contra dancing, salsa, ballet, tap, country and others.

  • Elliptical

    As the body ages, running and jogging can take a toll on the joints, knees or back and potentially cause injury. An elliptical cross-training machine is an alternative to running, which still gets your heart rate up but at a <a href="http://www.mayoclinic.com/health/elliptical-machines/AN01620" target="_hplink">lower impact</a>.

  • Strengthening Exercises

    You can take a simple walk to the next level by bringing weights along to build strength in your arms and boost the cardio benefits. Strength-building techniques like pushups, squats and lunges are easy to do at home or can be squeezed into buckets of free time throughout the day.