New study shows only how much—and how fast—you should jog
In 2013, about 54 million Americans went running at least once, and nearly 30 million ran 50 times or more.1 Many of these people weren’t just jogging around the block. Over half a million finished a marathon (26.2 miles) and nearly 2 million completed a half-marathon.2,3
This may seem like a ray of hope amidst all of the gloom and doom about Americans’ sedentary lifestyles. But is all of this running around really getting us anywhere in terms of genuine good health and longevity?
Another new study says no.
The Danish study followed nearly 1,100 healthy joggers and about 4,000 healthy non-runners for 12 years. The joggers kept track of their hours, frequency, and pace of running.
And the researchers found that the most strenuous joggers were just as likely to die as those who were completely sedentary.
This finding is even more striking when you consider the joggers in the study tended to be younger than their sedentary counterparts. They also had lower blood pressure and body mass index, along with lower rates of smoking and diabetes.
But excessive running was still killing them.
Meanwhile, the light-to-moderate exercisers reduced their mortality rate by a whopping 30 percent.4
Based on this data, the researchers concluded that the “dose” of running that’s best for extending longevity is just 1 to 2.4 hours per week or less. And the best pace was slow-to-average, or about a 12-minute mile.
Slow and steady wins the race
This finding builds on past studies I have reported, showing that strenuous exercise does more harm than good. As you know, I often advise about the health benefits of moderate physical activity, but warn against the dangers of excessive exercise. Especially when it comes to joint and heart health.
The human body isn’t a machine, but the laws of physics and mechanics still apply. Grinding and pounding fragile joint cartilage by running on hard surfaces for hours at a time causes wear and tear—and the body just can’t keep up.
It’s not rocket science, just basic physics. The force applied to your joints is the speed at which your legs encounter and bump against hard surfaces, multiplied many times by your body weight—and it gets transmitted directly into your bones and joints.
The same kinds of problems happen with the abused hearts of extreme athletes.
The heart is a muscle, continuously beating. Even though a contracted heart is only about the size of your fist, it still has to pump blood all through your body. When it starts beating too fast—like when you’re running excessively at high speed—there is not enough time for it to fill up properly with blood between beats.
When the heart is repeatedly abused like this, the stresses and strains on the muscle and nerve fibers can lead to permanent damage. Some researchers believe that excessive exercise also leads to abnormal structural remodeling of the heart and blood vessels—creating “monstrous” organs that are not healthy over the long term.
So, as always, remember the golden rule: moderation in all things. Overdoing jogging or any other type of exercise is not only useless for your health, it is actually harmful to your health.
Sources:
1 “2014 State of the Sport—Part II: Running Industry Report.” Running USA. (www.runningusa.org), 6/15/14
2 “Running USA Annual Marathon Report.” Running USA. (www.runningusa.org), 3/23/14
3“Running USA Annual Half Marathon Report.” Running USA. (www.runningusa.org), 4/6/14
4 “Dose of Jogging and Long-Term Mortality: The Copenhagen City Heart Study.” J Am Coll Cardiol. 2015; 65(5):411-419.