Is everything you think you know about running wrong?
While stretching is out of favour, scientists still reckon you need to warm up before a workout. That means walking before a brisk walk, or jogging before a run, with maybe a few vigorous exercises such as skipping or bottom kicks. Ibuprofen is deemed worthless for warding off muscle pain, and cryogenics and ice-baths might only work because the masochists who endure them think they do.
As for warm-ups, Reynolds suggest skipping them if you wish. She quotes Jack LaLanne, an early American fitness guru who lived to the age of 96: “Fifteen minutes to warm up! Does a lion warm up when hes hungry? Uh-oh, here comes an antelope. Better warm up. No! He just goes out and eats the sucker”.
Researchers are similarly sceptical these days about the virtues of carbo-loading. For most of us exercising for an hour or less, the amount of additional carbohydrates needed is minimal. A normal, healthy diet will supply more than enough fuel for moderate exercise lasting up to 90 minutes.
This changes if you’re running a marathon but it seems the carbohydrates you eat during a long workout or race are the most important for performance. So, Reynolds advises, bring your carbs with you – as an energy bar, for example – and avoid binge drinking while exercising.
The emphasis on endurance can lead many athletes to neglect the virtues of strength training, which confers considerable physiological benefit and can help counteract the effects of ageing, according to the book. Reynolds suggests you determine how strong you are by dropping to the floor and performing as many full-body push-ups as you can. Apparently, the average 40-year-old man should be able to complete about 27 push-ups before becoming exhausted, while women of the same age should be able to do 16.
To avoid injury, she advises runners to strengthen their knees through specific exercises and achieve better form, while counselling that “less shoes is probably best”.
The good news from science is that exercise seems to have a significant anti-ageing effect. One study has found that active twins are biologically younger, while another found that runners’ knees were actually healthier than non-runners’ knees when tested after a gap of 20 years.
But while exercise is undoubtedly beneficial, does it outweigh the problems caused by inactivity? In recent years, scientists have developed the notion of the “active couch potato”, someone who runs or goes to the gym at lunchtime but is sedentary much of the rest of the day. According to one US study, isolated bouts of exercise failed to ameliorate the risk of heart disease and cancer caused by inactivity. People who exercised for at least seven hours a week but spent at least five hours a day in front of the television were more likely to die prematurely than the small group who worked out seven hours a week and watched less than an hour of television a day.
So, the message seems to be, keep moving, whether in planned exercise or simply by standing up, or doing the ironing, or finishing an article and getting out for some fresh air.
The First 20 Minutes: The Surprising Science of How We can Exercise Better, Train Smarter and Live Longer
By Gretchen Reynolds (Icon Book £12.99)