New Scientist 14Mar2020

38 | New Scientist | 14 March 2020

Steve Haake is at Sheffield Hallam

University, UK, and author of

Advantage Play: Technologies

that changed sporting history

COURTESY OF PARKRUN

injured, sustaining around 18 injuries per 1000

hours of exercise. At an average pace of nearly

10 kilometres per hour, this is equivalent to

about one injury every 540 kilometres, more

than double the rate of more experienced

runners. Unsurprisingly, one of the most

important risks is the existence of a previous

injury. “I think learning how to run sensibly and

properly can help mitigate those risks,” says

Lieberman (see “Avoiding the downsides”, left).

Weighty issue

But what about those terrifying stories of

people who cross a marathon finish line only

to drop dead? Some studies show that the

health benefits of running tail off, or even

reverse, when running more than 4.5 hours

a week. Crucially though, the risks from any

amount of running are always lower than from

doing no running at all and, on average,

runners live three years longer than non-

runners. “People who engage in high amounts

of running still have health benefits compared

to non-runners, but there is probably a point of

diminishing returns,” says Brellenthin.

There is good news for runners on the

obesity front too: runners tend to weigh less

than walkers. This could be because thinner

people are more likely to run, but a study by

Williams suggests running helps shed excess

weight. It showed that reductions in body mass

index were significantly greater from running

compared with walking when these activities

were matched for energy expenditure. This

could be due to a greater increase in metabolic

rate after more intense exercise.

So where does this leave us in the walk/run

debate? Was my PE teacher right that running

is a better way to exercise than walking?

The research clearly shows that both are

good for you. They improve cardiorespiratory

fitness and reduce blood pressure, body mass

index and the risk of a host of diseases. For the

biggest bang for your buck though, running

has the edge, mostly because you can get more

exercise done in a given time. But if you

expend the same amount of energy when you

walk, the benefits are quite similar. In other

words, if you prefer walking, go for a long one,

ideally with a few hills. And remember that any

amount of exercise is better than none.

This philosophy might explain the success of

an exercise phenomenon that is sweeping the

globe: parkrun. These free, timed 5-kilometre

community events take place every Saturday

morning in more than 20 countries. They are

wildly popular, with 6 million people signed

up. Key to parkrun’s success is that you can

cover the distance however you want: by

running, walking, pushing a child in a buggy

or loping with a dog. Participants rate the

impact on their fitness and happiness so

highly (I know, because I carried out the

research to find out) that family doctors in

the UK now prescribe parkrun to their patients.

My PE teacher would be astonished to

discover that I enjoy running now and

rarely miss a parkrun. If I did meet him,

though, I would gently point out that we don’t

necessarily have to run. After all, the most

important exercise is the one you actually do. ❚

AVOIDING THE DOWNSIDES

Rebecca Robinson is a doctor specialising

in sports medicine at the Centre for Health

and Human Performance, London, and an

elite marathon runner. Here are her tips

for avoiding running’s drawbacks.

SLOW BUILD-UP

The forces that bones experience during

running are much higher than for walking.

Following a training programme that gets

progressively more intense can promote

bone growth, and strengthen the muscles

that can absorb more force, as well as

associated ligaments and tendons.

MIX IT UP

Bone strengthening in adults happens only

in the direction of the load placed on it, so

combining running with multidirectional

strengthening exercises can maximise the

whole-body benefits. A balance of running

and “resistance training” such as gym

workouts, yoga or Pilates can build up

muscle and bone. For experienced runners,

trail and mountain running mixes up the

direction of the loads placed on the body.

YOU’RE NEVER TOO OLD

Running plus resistance training can

maintain the muscles that support joints.

This is true even as we age. Muscle mass

peaks in our 20s and 30s, then naturally

declines. However, strength, endurance

and balance training even into our 70s, 80s

and 90s counteracts this. This is important

for keeping older runners on the move,

and protects against falls and frailty.

REST

Our bones need a recovery period to adapt

to the loads they experience. Too much

load can outstrip the ability of bone to lay

down new cells, which can result in a

debilitating stress fracture. So remember

that rest is training too.

DON’T SWEAT IT

Physical activity can be very beneficial for

mental health, including depression and

anxiety. However, overtraining can lower

mood, as can focusing too intently on the

results of training. Finding the right balance

between enjoyment and striving is key.

On a parkrun, it is

still 5 kilometres

whether you walk,

jog or go flat out