Energy expenditure of extreme competitive mountaineering skiing

Multi-hour ski mountaineering energy balance may be negative and intake below recommendations. Athletes on the 'Patrouille des Glaciers' racecourses (17 on course Z, 27 km, +2,113 m; 11 on course A, 26 km, +1,881 m) volunteered. Pre-race measurements included body mass, stature, VO2max, and heart rate (HR) vs VO2 at simulated altitude; race measurements HR, altitude, incline, location, and food and drink intake (A). Energy expenditure (EE) was calculated from altitude corrected HR derived VO2. Race time was 5 h 7 min +/- A 44 min (mean +/- A SD, Z) and 5 h 51 min +/- A 53 min (A). Subjects spent 19.2 +/- A 3.2 MJ (Z), respectively, 22.6 +/- A 2.9 MJ (A) during the race. Energy deficit was -15.5 +/- A 3.9 MJ (A); intake covered 20 +/- A 7 % (A). Overall energy cost of locomotion (EC) was 9.9 +/- A 1.3 J m(-1) kg(-1) (Z), 8.0 +/- A 1.0 J m(-1) kg(-1) (A). Uphill EC was 11.7 +/- A 1 J m(-1) kg(-1) (Z, 13 % slope) and 15.7 +/- A 2.3 J m(-1) kg(-1) (A, 19 % slope). Race A subjects lost -1.5 +/- A 1.1 kg, indicating near euhydration. Age, body mass, gear mass, VO2max and EC were significantly correlated with performance; energy deficit was not. Energy expenditure and energy deficit of a multi-hour ski mountaineering race are very high and energy intake is below recommendations.