Rio is not the ideal place to buck this trend. For a start, it lies at sea level. This is a boon to beach volleyball players, who get to compete in their discipline’s spiritual home on Copacabana. But it is a bane for many track-and-field athletes, because it means air in Rio is denser than at higher altitudes, and drag greater. This matters to sprinters, jumpers and throwers, whose effort is mostly anaerobic, and therefore less affected by the extra oxygen. One explanation for the above-trend track-and-field performance in 1968 was that the Olympic games that year were held in Mexico City. At an altitude of 2,240 metres the air is a fifth thinner than in Rio, providing 20% less resistance. Eight of that year’s 25 best results for the 100 metre dash were recorded at the games. Most of the rest were notched up by athletes preparing for Mexico City at high altitudes. And then there was Bob Beamon’s record-smashing 8.9 metre long-jump.
Long-distance runners will no doubt enjoy Rio’s abundant oxygen. But not its subtropical heat. Although the city has been unseasonably chilly, with temperatures falling as low as 11 degrees celsius at night, the coming days are forecast to be balmier. This will be pleasant for spectators, but does not augur well for long-distance runners. The best marathon times, for instance, are notched up in races such as Berlin’s, where temperatures throughout the course range between 10 and 16 degrees Celsius. This is unlikely both this Sunday morning, when the women race, or during the men’s event a week later, meteorologists predict.