What comes back

If the stiffness and tiredness were age, there'd be nothing to discuss. The reason to separate out disuse is that it can be undone, and the evidence for that is better than you might expect.

Go back to the five men from Dallas. When the researchers found them again at fifty, they did more than measure them. They put them on a six-month training programme of walking, jogging and cycling, building up gradually. At the end of the six months they measured the men's maximal oxygen uptake again. It had risen by 14 per cent, which took it back to the level recorded before the bed rest in 1966. The researchers put it strikingly. One hundred per cent of the decline in aerobic power that had taken place over thirty years was reversed by six months of training.

There were limits, and the researchers reported those too. None of the men got back to the peak he'd reached at twenty after the hard training that followed the bed rest. Age had taken that peak away. What came back was the large, ordinary loss that three decades of desk life had laid on top.

It's five men again, so don't read the 100 per cent as a promise. Read it as a demonstration that the process can run backwards in a fifty-year-old.

It can run backwards a great deal later than that. Maria Fiatarone and colleagues ran a trial in a nursing home in the United States. The hundred residents who took part were frail, and their average age was eighty-seven. The oldest was ninety-eight. Half were given progressive resistance training for their legs three times a week for ten weeks, which means exercises against a weight that was increased as they got stronger. Over those ten weeks the strength of the trained group more than doubled, with an average gain of 113 per cent. The untrained group gained 3 per cent. The trained residents walked faster and climbed stairs with more power. They also began moving about more of their own accord, the mirror image of what Kortebein saw after bed rest. Ninety-four of the hundred completed the study.

I find that study moving. The people in it were about as far along as a person gets, and their muscles still responded to being asked. If it works at eighty-seven in a nursing home, the mechanism hasn't switched off at fifty-four.

As for what you can expect for yourself, the studies I've described used proper training, and the rule in the next chapter is gentler than that, so I'll give you my expectations and label them as such.

Within the first week or two, the stiffness on standing should be noticeably less, for the plain reason given in chapter 5. You won't have been still long enough for it to build. This is the quickest return, and you can confirm it within a day.

Over the first few weeks, I'd expect the afternoon slump to soften and the evenings to feel less flat. That's going by Thayer's result, the larger reviews, and what people commonly report. Don't expect it to vanish. Sleep and food and the nature of your job all have a say in it.

Over a few months, I'd expect some items to move back from the second list to the first. The stairs will be less of an event. Getting up from the floor will need less furniture. These come back slowly, because rebuilding capacity takes longer than easing stiffness, and they'll come back faster if you add the strength work described at the end of the next chapter.

The breaks and the walk on their own won't make you fit, and they won't alter your weight or the shape of your body. I make no claim about either. Fitness takes training, as it did for the Dallas men. What the rule does is stop the daily instruction to your body that nothing will be required of it. If you then want to go further, you'll be starting from a better place, and with more energy to do it.