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Table 1 Aerobic and anaerobic energy expenditure for 2 exercise tasks of equal work

From: Misconceptions about Aerobic and Anaerobic Energy Expenditure

Measure

Steady rate walk

Intermittent sprints

Exercise O2

120 kJ

16 kJ *

Exercise O2 + EPOC

149 kJ

165 kJ

Anaerobic + Exercise O2 + EPOC

164 kJ

273 kJ *

  1. Each of the tasks involved 27.1 ± 2.3 kJ of treadmill work. Anaerobic energy expenditure was measured as the O2 deficit. Steady rate exercise required 3.5 minutes and was performed at 47% of VO2max. Intermittent exercise was completed as three 15-sec sprints at ~177% of VO2max. The * indicates a statistical difference from the steady rate value. Both the significant and non-significant findings have importance. For example, without a reasonable estimate of anaerobic energy expenditure it may be falsely concluded that the energy expenditure (i.e., exercise O2 uptake + EPOC) for these two walking and sprinting tasks was similar (149 vs 165 kJ, respectively) when they are significantly different (164 vs 273 kJ, respectively) (adapted from [26]). The estimate of anaerobic energy expenditure also reveals that this component is not significant for the low intensity steady rate walk (149 vs 164 kJ) but it is for the intense intermittent sprints (165 vs 273 kJ). Based on exercise O2 uptake between the steady rate walk and intense intermittent sprints (120 vs 16 kJ, respectively) it was concluded that O2 uptake is an invalid measure of exercise energy expenditure for brief intermittent severe exercise