The Rundown

Is Running Bad For Your Knees? A recent meta-analysis examined 17 studies with just over 7000 runners and just under 7000 non-runners to determine the effects of running on the development of knee osteoarthritis. The mean age of the runner group was 56 with an average follow-up time of four and a half years while the mean age of the non-runner group was 62 with a follow-up time of eight years.

The researchers found that there was a higher prevalence of knee pain in the non-runner group and no significant differences in the prevalence of radiographic knee osteoarthritis between runners and non-runners. One study in the analysis found higher risk of knee osteoarthritis progressing to total knee replacement among non-runners (4.6% compared to 2.6% for runners).

The takeaway: In the short term, running was not associated with a worsening of knee pains or radiological signs of knee osteoarthritis and may be protective against generalized knee pain.

Kids+Exercise=Less Stress. For adults, movement is typically recommended to reduce stress. But does it also help children manage it? A study from the University of Basel recently looked at the effect of physical activity on kids’ stress levels.

Over 100 children between 10 and 13 years old wore a sensor for a week to track their daily movement. On two different occasions, they were brought to a lab to complete a *stressful task and a non-stressful task. The researchers tested the children’s physical stress reaction through the concentration of cortisol in their saliva.

The results showed that kids who got more than an hour of exercise per day produced less cortisol in the stress task than those who were less active.

One possible explanation for the result is that cortisol levels also increase during exercise so the brain may learn to associate a rise in cortisol with something positive. This positive association in turn helps to prevent the concentration of cortisol from rising too high.

*The study uses the Trier Social Stress Test for Children. In part one, the kids read a story with an open ending and have five minutes to prepare before using their notes to tell the rest of the story to a panel of people. The preparation time is intentionally short so after about a minute, the kids’ notes are mostly exhausted but they still have to fill time and think of something to say. For part two, they have to repeatedly reduce a number in the high three digits by a certain value over five minutes. If they make a mistake, they have to start from the beginning.

Extra Point

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The Deepest Breath. This documentary has been described as Free Solo for free diving. And if you’ve seen the nail biting climbing movie, you’ll recognize the anxiety-inducing narrative style as you watch this story. It follows record-setting free diver Alessia Zecchini and expert safety diver Stephen Keenan as they attempt to make history with a notoriously difficult dive. Their fate is constructed as a plot twist, which could seem exploitative or clever depending on your point of view. The deep ocean footage is beautiful. The Deepest Breath is streaming on Netflix.

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30 for 30 Podcasts. The makers of the 30 for 30 film series on ESPN have a podcast based on the documentaries and it turns out, they work just as well without the visuals.

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Why We Sleep: Unlocking the Power of Sleep and Dreams. Dr. Matthew Walker, director of UC Berkeley's Sleep and Neuroimaging Lab, combines science and a lyrical writing style in this book filled with information on how to use the transformative power of sleep.