Heart rate response to professional road cycling: The Tour de France

The aim of the present investigation was to evaluate the heart rate respons e of 8 professional cyclists (26 +/- 3 yr; 68.9 +/- 5.2 kg; (V) over dot O( 2)max: 74.0 +/- 5.8 mi . kg(-1) . min(-1)) during the 3 week Tour de France as an indicator of exercise intensity. Subjects wore a heart rate telemete r during 22 competition stages and recorded data were analysed using comput er software. Two reference heart rates (corresponding to the first and seco nd ventilatory thresholds or VT1 and VT2) were used to establish three leve ls of exercise intensity defined as phases I (<VT1), II (VT1 -VT2) and III (<VT2). The average total time spent by each subject in each of the 3 phase s respectively was approximately 71, 23 and 8 h. The relative contributions of each phase were 70, 23 and 7 %. The percentage relative contribution of each phase was significantly different (p < 0.01) in each of the competiti on stages (time trials, flat stages, "high-mountain" stages and "medium-mou ntain" stages). Exercise intensity was particularly high during the time tr ials and high mountain stages. It may be concluded that during an endurance event such as the Tour de France, although the overall contribution of mod erate (VT1 to VT2) or high intensity exercise (> VT2) is substantially lowe r than that of light, aerobic exercise (<VT1), a clear distinction must be made between the different type of stages (i.e. easy, flat parcours vs moun tain stages or time trials) and the role of each cyclist in the team must b e also considered.