text:  The Tour de France is kicked off during a heat wave in southern Europe. The 21-day-long cycling race is considered one of the world's most grueling athletic endeavors. As NPR's Alejandro Barunda reports, heat management is now a new focus for the riders. The race started this weekend in Florence, Italy, and the first day, temperatures neared 100 degrees. A famous cyclist, Marc Cavendish, threw up on his bike.