Exercise and company
Fitter with friends
From The Economist print edition
Exercising in a group can be more effective by making things easier
All together now
THE enduring image of Sylvester Stallone’s legendary pugilist Rocky Balboa is that of a solitary athlete, braving the elements (and his own demons) to prepare for a fight. Yet according to a new study he might have done better by having a bit of company on his long workouts.
Research by Emma Cohen, an anthropologist at Oxford University, suggests that a better model is provided by Hicham El Guerrouj, a Moroccan middle-distance runner who is the current holder of the world 1,500-metres and one-mile records. Before retiring in 2006 Mr El Guerrouj was known for the throngs of training partners that followed him everywhere in Morocco. This was a good strategy because, as Dr Cohen reports in a forthcoming issue of Biology Letters, training in a synchronised group may heighten tolerance for pain. That, in turn, could allow athletes like Mr El Guerrouj to train longer and harder.
The reason is almost certainly the effects of endogenous opioids, better known as endorphins. When these are released in the brain they make a person feel good. What causes their release is more complex. Biologists think it is part of an evolved mechanism which rewards behaviour that may not be immediately pleasant but is ultimately useful to the species.
Endorphins show up nearly everywhere. Hunting an animal may be tiresome but necessary, so endorphins are secreted during exertion to numb the discomfort induced by lactic acid production in the muscles. Collaboration makes it easier to kill animals while others set traps.
Dr Cohen wanted to see if combining exercise and collaboration would heighten the effect. One of the study’s co-authors, Robin Ejsmond-Frey, rowed for Oxford and thought it would be a good activity to study. For one thing, it is easy to spot a crew that is not well synchronised. Secondly, ergometers (machines on which rowers train) provide data on the power exerted on each stroke. And it can be rather painful so the endorphins should be out in droves.
The researchers got 12 members of Oxford’s heavyweight squad to row on machines in four 45-minute sessions over two weeks. In two sessions they rowed in complete isolation and in the others in groups of six, perfectly synchronised. Immediately following each session their endorphin levels were tested. Because endorphin levels can only be measured directly through an invasive lumbar puncture—unfeasible, even for notoriously pain-hungry oarsmen—the researchers used a readily accepted proxy: they deduced pain tolerance, and hence endorphin levels, by gradually tightening a cuff around each rower’s arm. When he said “now” they stopped squeezing and noted the pressure.
As expected, the rowers’ pain thresholds were significantly higher following the group sessions. This was despite nearly identical power outputs in all four tests and efforts to control for possible confounding variables, such as the time of day.
The athletes may be rewarding themselves for their collaboration. Whether heightened tolerance is due specifically to rowing synchronously remains unclear. Data from other studies suggest that co-ordinated physical exercise can heighten social bonds (as in military training). The reverse may also be true. As the rowers had been teammates for nearly a year it is possible that the mere presence of friends explains the observed effect. The researchers are keen to replicate the study to test for such things. Meanwhile, solitary joggers might want to take along a friend or two.
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