The impact of 100 hours of exercise and sleep deprivation on cognitive function and physical capacities

In this study, we examined the effect of 96-125h of competitive exercise on cognitive and physical performance. Cognitive performance was assessed using the Stroop test (n=9) before, during, and after the 2003 Southern Traverse adventure race. Strength (MVC) and strength endurance (time to failure at 70% current MVC) of the knee extensor and elbow flexor muscles were assessed before and after racing. Changes in vertical jump (n=24) and 30-s Wingate performance (n=27) were assessed in a different group of athletes. Complex response times were affected by the race (16% slower), although not significantly so (P=0.18), and were dependent on exercise intensity (less so at 50% peak power output after racing). Reduction of strength (P0.05) of the legs (17%) and arms (11%) was equivalent (P=0.17). Reductions in strength endurance were inconsistent (legs 18%, P=0.09; arms 13%, P=0.40), but were equivalent between limbs (P=0.80). Similar reductions were observed in jump height (-89%, P0.01) and Wingate peak power (-715%, P=0.04), mean power (-711%, P0.01), and end power (-1011%, P0.01). We concluded that: moderate-intensity exercise may help complex decision making during sustained stress; functional performance was modestly impacted, and the upper and lower limbs were affected similarly despite being used disproportionately.