I'm a big cycling fan. Yes, they are all VERY fit. Miguel Indurain, who won the Tour 5 times in the 90's, once said his at rest heartbeat is 21!
Also, unlike most overpaid footballers who trip over their laces and have to have 2 months off to recuperate, they will have big crashes and get back on their bikes with blood streaming down arms and legs. Richie Porte once rode for a week with a broken arm! Tom Simpson collapsed on Mont Ventoux and his words were "put me back on me bike!". Sadly, he collapsed again and later died in hospital...one of 3 men to have died on the Tour. In case you didn't know, on the 'rest' days (the two middle Mondays), they will still go and do 150 mile ride to 'keep in trim'!