tour de france

Written By Asker Jeukendrup for mysportscience.com
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It is often said that the Tour de France is perhaps the most gruelling endurance event on the planet. The same is sometimes said about Ironman. We saw in my previous blog that energy expenditure in the Tour de France averages almost 6000 kcal per day for 3 weeks (5).  It has been measured that energy expenditure can be as high as 9000 kcal per day. How does this compare to other sports? Is this really the most extreme sport? Is it Ironman… Or is there another event?

In the literature we can find energy expenditure values for a number of events and I have tried to find the highest values for energy expenditure in the literature. If someone knows of other papers that report extreme values please let me know and I will update this list.

There is a report of a male distance runner covering ∼100 km/day for 1,000 km (1), He averaged around 6,000 kcal/day.

Another report describes 2 elite cyclists averaging around 330 km/day for 10 days and expending 7,000 kcal per day (2)

There is also a report of a team of elite cyclists expending 6,500 kcal/day who covered nearly 4,900 km in 6 days during the Race across America (RAAM) (3).

Similar values were also reported in cross country skiers during intense training (6,000 kcal/day) (6).

Dr Mike Stroud, a Polar explorer and researcher, measured energy expenditure in man-haulers over several polar expeditions during the 1980s and 1990s (7). Before these studies the very high energy costs of polar travel on foot appreciated. During a modern-day, one-way expedition to the South Pole that repeated Scott’s route (“Footsteps of Scott expedition”), an average of 6,000 kcal were expended every 24 h. Mike Stroud himself together with Sir Ranulph Fiennes crossed Antarctica by foot and expended on average nearly 7,000 kcal/day.

During this crossing there was a period of approximately 10 days, while ascending to the plateau, during which they averaged nearly 11,000 kcal/day).

A recent study by Dr Brent Ruby and Colleagues (4) compared measurements at Ironman Hawaii (2.4 mile swim, 112 mile bike and 26 mile run (3.8km; 180km and 42km respectively) and the Western State 100 (a 100 mile (160km) ultramarathon). Energy expenditure during the Hawaii Ironman averaged 9,040 kcal (plus or minus 1,390 kcal). In the Western State energy expenditure was as high as 16,310 kcal (plus or minus 2,960) but of course the duration of this event was more than 24 hours on average (26.8h).

It is clear that daily energy expenditure can be much higher than the reported average of 6000 kcal per day for the Tour de France cyclist. Values can be even higher than the extreme values reported during the longest and hardest days in the Tour.

What make the Tour de France unique though is that these extreme energy expenditures are achieved within 4-6 hours of racing per day and also that this is sustained over a period of 3 weeks.

Most other sports with extreme energy expenditures achieve their high numbers by exercising more hours per day at a lower intensity and sometimes by eliminating sleep.

Which is the most extreme sport? Difficult to say… would you rather do a day in the Tour than a day crossing Antartica, or running a 100 mile race in the heat without sleeping?

References 

1. Eden B, Abernethy P. Nutritional intake during an ultraendurance running race. International J Sports Nutr 4: 166–174, 1994.

2. Gabel K, Aldous A, Edgington C. Dietary intake of two elite male cyclists during 10-day, 2,050-mile ride. Int J Sports Nutr 5: 56–61, 1995.

3. Hulton A, Lahart I, Williams K, Godfrey R, Charlesworth S, Wilson M, Pedlar C, Whyte G. Energy expenditure in the race across america (RAAM). Int J Sports Med 31: 463–467, 2010.

4. Ruby BC, Cuddy JS, Hailes WS, Dumke CL, Slivka DR, Shriver TC, Schoeller DA Extreme endurance and the metabolic range of sustained activity is uniquely available for every human not just the elite few. Comparative Exercise Physiology, 11(1): 1-7, 2015.

5. Saris WH, van Erp-Baart MA, Brouns F, Westerterp KR, ten Hoor F. Study on food intake and energy expenditure during extreme sustained exercise: the Tour de France. Int J Sports Med;10 Suppl 1:S26-31, 1989

6. Sjodin A, Andersson A, Hogberg J, Westerterp KR. Energy balance in cross-country skiers: a study using doubly labeled water. Med Sci Sports Exercise 26: 720–724, 1994.

7. Stroud M, Coward W, Sawyer M. Measurements of energy expenditure using iso- tope-labelled water (2H218O) during an Arctic expedition. Eur J Appl Physiol 67: 375– 379, 1993