Interpreting Anaerobic and Total Energy Expenditure for Brief Non-Exhaustive Exercise and Recovery

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Medicine & Science in Sports & Exercise


Indirect estimates of anaerobic energy expenditure are often derived from exhaustive and/or intermittent exercise that lasts minutes. PURPOSE: To compare four indirect interpretations of anaerobic and total energy expenditure during brief, non-exhaustive exercise lasting seconds. METHODS: Aerobic energy expenditure along with four indirect measures of anaerobic energy expenditure were examined in 9 subjects, 1) O2 debt, 2) O2 deficit, 3) blood lactate and 4) excess CO2 production (RER > 1.00) during and after six exercise durations (2, 4, 10, 15, 30 and 75 sec) performed at three different intensities (50%, 100% and 200% of VO2max). Comparisons were made among each interpretation of anaerobic energy expenditure and total energy expenditure using 1 and 2-way ANOVA. RESULTS: The O2 deficit indicated the largest anaerobic and total energy expenditure, the O2 debt often resulted in the lowest anaerobic and total energy expenditure (p < 0.05); blood lactate measurements fell inbetween. Blood lactate only differed from the O2 debt at the highest exercise intensity (p < 0.05); blood lactate tended to increase as duration increased (NS). Excess CO2 production indicated zero glycolytic energy expenditure except at the higher intensities and longer durations. CONCLUSION: Problems exist for all indirect methodologies and subsequent interpretations of anaerobic and total energy expenditure. However, if the O2 debt does not adequately represent the bioenergetics of rapid glycolysis with lactate production during exercise, then the O2 deficit at all workloads and blood lactate measures at the higher workloads are the only methods to include a significant glycolytic/lactate component to anaerobic and total energy expenditure for brief nonexhaustive exercise.


©2004 The American College of Sports Medicine