Racing in hot, humid conditions which could be made worse by pollution levels is not the only thing worrying Alejandro Valverde, Spain's big favourite for the Olympic cycling road race this Saturday.
Valverde comes into the 248.5km race - said to be one of the toughest ever at an Olympics - fresh from the Tour de France where he finished ninth overall and won the opening stage.
As one of the most feared all-rounders in the business, Valverde could be the man to succeed formidable Italian Paolo Bettini, the world champion for the past two years.
The 28-year-old Spaniard admits his five-man team will have to "race at the front" throughout in a bid to hold off strong challenges from Bettini, and an equally strong German team.
But Valverde also believes Luxembourg's Kim Kirchen, a member of a team which also includes the talented Schleck brothers Andy and Frank, must also be considered a gold medal contender.
Kirchen came close to winning a stage several times on the Tour and wore the overall leader's yellow jersey for four days.
"I believe Kim (Kirchen) is the rider whose characteristics are best suited for this course. We saw he was very strong in the Tour de France," Valverde said Tuesday. "He is the fastest of the three and he is the most dangerous."
A combination of tactical nous and sheer leg power will be crucial over a course whose main climb will be tackled seven times. But the climbers looking for gold on the uphill finish will also be expected to possess a winning sprint - a speciality of Valverde, Bettini and Kirchen among a few select others.
Valverde, a two-time winner of the hilly Liege-Bastogne-Liege one-day classic in Belgium, could be spurred on by the knowledge he has twice finished a runner-up and once third in the world road race championships.
Team-mate Samuel Sanchez believes another special ingredient could motivate Valverde further.
"For many of us, it will be the last time we compete in an Olympic Games, so we will approach it with more intensity and more emotion," said Sanchez.
Yet Valverde knows they won't be given anything for free.
"We're one of the most important teams in the race but Germany and Italy are also strong," added the Spaniard, highlighting the fact that only five riders, and not nine as at the world championships, are permitted to represent a country at the Olympics. And we have to remember this is not the world championships. It's the Olympic Games, so it is completely different from other types of racing."
Valverde's team also includes sprinter Oscar Freire, 2007 Tour de France champion Alberto Contador and newly-crowned yellow jersey king Carlos Sastre. On paper, they will be hard to beat. But on the day, what is likely to turn into a race of attrition could be made even tougher by the climatic conditions.
"When we got off the plane we immediately noticed the pollution," added Valverde. "I can't say too much (about the course) because we haven't seen it yet. But from what I hear it's going to be quite challenging. Also, because of the heat, humidity and pollution, it is going to be very demanding. For us, the most important thing will be to see the climb. We are going to drive 20km outside the Olympic Village to be closer to the route that we will use on Saturday."
© BikeRadar & AFP 2008