The purpose of the present case study was threefold: (a) to estimate intake and expenditure of a dog driver (musher) while participating in the Iditarod, (b) to determine the hydration status of the musher at the completion of the event, and (c) to evaluate training related changes in aerobic capacity and body composition of a long-distance dog sled driver in preparation for and following completion of a 1049-mile (1692-km) sled dog race. Actual energy intake during the Iditarod Sled Dog Race was estimated at 8,921 kilojoules (kJ) per day. Nutrient intake expressed as percentage kJ of total energy (14%, 44% and 42% for protein, carbohydrates, and fat, respectively). Weight loss of .72 kg of body weight indicated an energy deficit of 1819 kJ per day during the race. Total energy needs per day were calculated to be 10,740 kJ/day. An increase in hematocrit and hemoglobin during the race may indicate dehydration during the event. There was an improvement in aerobic fitness during on-snow training as determined by ventilatory threshold and VO2peak data. Fat-free mass was maintained during training (46.4 kg), with a concomitant decrease in fat (2.4 kg). Fat-free mass was also maintained during the 12-day race.
The authors are with the Department of Health and Human Performance at the University of Montana, Missoula, MT 59812-4536.