Modernity made movement optional

In a famous study in Dallas, five healthy 20-year-old men agreed to spend three weeks in bed. They were not ill or injured. They were fit young volunteers, and their job was to lie still. When they got up, their aerobic capacity, the most oxygen their bodies could use, had fallen by 26 percent.

Thirty years later, researchers found the same five men and tested them again. They were 50 now, and heavier. Yet three decades of getting older had cost them only 11 percent of that capacity. Three weeks in bed at 20 had done more harm than 30 years of ageing.

Then, at 50, the men trained for six months. By the end, they had won back everything the 30 years had taken.

A healthy young man in a red T-shirt lies flat on a hospital bed, playing cards with a visitor. He is a volunteer in a NASA bed rest study in Galveston, Texas, and a sign on the wall reads: Have a laid-back trip. — A volunteer in a NASA bed rest study, Galveston, Texas, 2008. Photo: NASA. Public domain.

01

Use it or lose it.

Your body keeps what you use, and lets go of what you do not. It does this quickly, and it does it in both directions. The men in Dallas lost fitness in three weeks, and at 50 they won it back, because they asked their bodies for more.

There is a second half to the rule, and it matters more to anyone who trains. Your body keeps exactly what you ask of it, and nothing else. Run, and it gets good at running. Ride, and it gets good at riding. It does not get better at carrying, squatting, lifting or getting up off the floor, unless something asks it to.

A line chart of leg muscle mass over 60 days of bed rest and two weeks of recovery. Volunteers who only lay in bed lost about 16 percent; volunteers who did short jump training sessions while lying down lost about 5 percent, and were back to their starting level a week after getting up. — Leg muscle during 60 days of bed rest, with and without jump training. From Kramer et al. 2017, Scientific Reports, CC BY 4.0.

02

An hour of training, a day in a chair.

For almost all of human history, life asked the body for all of it, every day. People walked, carried, dug, climbed, squatted and knelt, because the day demanded it. Then the car, the lift, the desk and the delivery van took those demands away, one by one. Movement became optional.

You chose to train, which is more than most people do. But look at the rest of your day. In one study, 218 people training for a marathon or half marathon trained for about six and a half hours a week. On workdays they also sat for nearly 11 hours. Researchers have a name for this: the active couch potato. An hour of hard training, then a commute, a desk and a sofa.

In one study, runners training for a marathon or half marathon sat for nearly 11 hours on workdays.

03

One movement is not enough.

A body that only runs or rides is doing one thing, many thousands of times, and very little else. The rest of what it can do goes unused, and what goes unused, it lets go.

You may already feel it. Around four in ten runners get injured in a year, depending on the study. Plenty of riders climb off after a long ride with an aching back, tight hips and a stiff neck. Endurance built the engine. Nothing in their week asked the rest of the body to keep up.

The research points the same way. In a review of 25 trials in many sports, the strength programmes cut injuries to less than a third. Stretching on its own did not prevent them. Your body wants load, range and variety, and running or riding alone gives it only one.

04

Every easy choice has a price.

The easy way is offered at every turn, and each time it looks free. It is not.

Take the supermarket. Push a trolley, and your body does almost nothing. Carry a basket, and your grip, your shoulders and the muscles around your middle work to hold you upright against the load. It is only a few minutes, but you shop every week for the rest of your life. Drive everywhere, and that time is spent sitting still with your hips bent. Walk or ride the same distance, and you arrive having trained.

Even rest is a choice. Sit on the floor to read a book or scroll your phone, and you fold your legs, shift your weight when you get stiff, and get yourself back up at the end. The sofa asks none of that. Researchers have found that adults who can sit down on the floor and stand up again without using their hands tend to live longer than those who struggle to.

No single choice matters much. Over years, they add up to a body that keeps its capability, or one that slowly gives it away.

A young woman rides a bicycle towards the camera with a bag of groceries in its front basket, while a sailor walks behind her carrying a paper bag of shopping under his arm. Greenbelt, Maryland, 1942. — Shoppers in Greenbelt, Maryland, 1942, during the wartime "I'll carry mine" campaign to save delivery vans. Photo: Ann Rosener, Office of War Information, Library of Congress. Public domain.

05

Put it back into your day.

None of this means giving up the car or the sofa. They are good inventions, and you are right to enjoy them. But you can put much of the missing movement back without finding a single extra hour, by folding it into things you already do.

Brush your teeth in a deep squat: feet flat, heels down, as low as you can go. For much of the world this is how people rest, and many adults raised in chairs can no longer get there. Brushing takes two minutes in the morning and two in the evening, so that is four minutes a day in the squat, for free. Hold on to the sink at first if you need to. The range comes back when you ask for it.

Carry your shopping home in bags, one in each hand. Take the stairs, two at a time on a good day. Walk while you are on the phone. Get down on the floor to play with a child or a dog, and get back up without using your hands.

Each one is small. Together they give your body a day that asks for more than one thing again, the way life used to.

What this means for you

Use it or lose it. Your body is only capable if you use it, all of it, and modern life no longer makes you. Your training builds the engine. The rest of your day decides whether the body around it keeps up. So carry the basket, walk when you could drive, brush your teeth in a squat, and pick the harder way up the hill.

It is your birthright to be an incredibly capable animal, and not only over a distance. A body that fulfils that birthright is the highest form of luxury.

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