Should you walk or run for exercise? Here's what the science says.

Is running really a better form of exercise than walking,
given that running can lead to more injuries?
At Vox, I sit next to health reporter Sarah Kliff, who
trains for half-marathons and triathlons with a
casualness most people reserve for grocery shopping.
But in the year I’ve known Sarah, she’s suffered plantar
fasciitis and a stress fracture. She’s hobbled around in
running shoes for months because everything else hurt
too much, and she’s currently sporting a big blue brace
on her left leg to help cushion the tiny cracks in the
bones of her foot brought on from too much wear and
tear.
In many ways, Sarah is a perfect case study in how to
think about the benefits and risks of running versus
walking. Running has greater health benefits than
walking (Sarah is super fit), but it also carries a much
bigger risk of injury (see Sarah’s foot brace).
So which effect dominates? To find out, I first searched
for "randomized control trials" and "systematic reviews"
on running, walking, and exercise at PubMed health (a
free search engine for health research) and in Google
Scholar . I wanted to see what the highest-quality
evidence — trials and reviews are the gold standard —
said about the relative risks and benefits of these two forms of exercise.
It was immediately apparent that running can lead to
more injuries, and the risk goes up as running programs
get more intense. Studies have found that runners have
significantly higher injury rates than walkers (one study
found that young men who run or jog had a 25 percent
higher risk of injuries than walkers), and that
ultramarathoners are at an even greater risk. The main
running-related injuries include tibia stress syndrome,
Achilles tendon injuries, and plantar fasciitis.
Overall, more than half of people who run will experience
some sort of injury from doing so, while the percentage
of walkers who will get hurt is around 1 percent.
Interestingly, it seems you can walk pretty much
endlessly without any increased risk of hurting yourself.
That running hurts people shouldn't be surprising. As
this study described , "Running produces ground
reaction forces that are approximately 2.5 times body
weight, while the ground reaction force during walking
is in the range of 1.2 times body weight." You're also
more likely to trip and fall while running than you are
during a walk.
JOGGING EVEN 5 TO 10 MINUTES PER DAY CAN REDUCE
THE RISK OF DEATH FROM ALL CAUSES
That said, I also learned about some of the incredible
health benefits of going fast: Even five to 10 minutes per
day of jogging at around 6 miles per hour can reduce the
risk of death from cardiovascular disease and other
causes. Joggers have been found to live longer than non-
joggers even after adjusting for other factors — a
difference of 3.8 years for men and 4.7 years for women.
That said, research has found that walking carries
significant health benefits, as well. Some studies
suggest that you can extend your life and stave off
disease by simply walking — and the more, the better.
All this research, while illuminating, didn’t offer up any
clear conclusions on whether running or walking was
better for you overall. So I asked some of the world’s
leading researchers in this area. Their conclusion? You
need to consider the trade-offs.
"Running moderately prolongs life more than walking
does," said Peter Schnohr, a clinical cardiologist who
has researched many aspects of exercise and health. The
key word there is "moderately." Schnohr warned of the
emerging research that very strenuous exercise (like
triathlon training) can lead to heart problems . Overall,
there's a U-shaped association between running and
mortality, he said. Too little isn't helpful for health, but
too much might be harmful.
"THE MOST FAVORABLE REGIMEN IS TWO TO THREE
RUNNING DAYS PER WEEK, AT A SLOW OR AVERAGE PACE"
"The most favorable [regimen] is two to three running
days per week, at a slow or average pace," Schnohr
advised. "Running every day, at a fast speed, more than
4 hours per week is not as favorable." And for those who
don't like running, he noted, "Fast walking, not slow,
also prolongs life. I can’t tell how much."
Dutch researcher Luiz Carlos Hespanhol pointed out that
in general, running simply delivers health benefits more
efficiently than walking does. This study, for example,
found that five minutes of running per day is as
beneficial as 15 minutes of walking. Hespanhol also said
that after one year of training just two hours a week,
runners lose weight, reduce their body fat, lower their
resting heart rates, and drive down their blood serum
triglycerides (fat in the blood). There's even evidence
that running can have positive effects on tension,
depression, and anger.
Even so, Hespanhol wasn't a total cheerleader for
running. A good walking regimen can have similar
benefits, he noted. So on running versus walking, it
really depends on your values and preferences: "One
could choose walking instead of running as a mode of
physical activity based on injury risks, since walking is
less risky than running," he explained. Or alternatively:
"One could choose running because the health benefits
are larger and come faster, in a shorter period of time."
To recap: Running improves your health more efficiently
than walking does and has greater health benefits per
time invested. But even a small amount of running
carries more injury risk than walking. And a lot of
running (i.e., ultramarathon training) can well be
harmful, while the same is never true for walking.
Where does this leave us? All the exercise researchers
seemed to agree on one thing: that the best exercise
routine is the one you'll actually do. So the answer to
the running versus walking question will probably vary
from person to person. If you prefer one over the other,
stick with that. And if you still can't decide, Hespanhol
suggested this: "Why not do both — running and walking

— in order to get the best of each?"