INTERPRETING ENERGY-EXPENDITURE FOR ANAEROBIC EXERCISE AND RECOVERY -AN ANAEROBIC HYPOTHESIS

Energy expenditure during and after exercise is composed of aerobic an d anaerobic bioenergetics and the energy demands of aerobic recovery. Current attempts to measure energy expenditure include an exercise oxy gen uptake + oxygen debt (EPOC) measurement or, an oxygen deficit + ex ercise oxygen uptake measurement. This investigation illustrates how o xygen debt and oxygen deficit interpretation can effect a total energy expenditure measurement. It was hypothesized that the total energy ex penditure for several intermittent bouts of exercise and recovery woul d be greater than for one bout of continuous exercise and recovery whe n equivalent work was compared. Exercise was performed under low-inten sity and high-intensity conditions. Both oxygen debt and oxygen defici t methodology resulted in similar energy expenditure measurements for both intermittent and continuous exercise. This implies little to no r ecovery energy demand or considerable methodology errors. Differences in total energy expenditure were found when the oxygen deficit and par ts of the oxygen debt (EPOC) were considered separate and independent (p<0.05). These differences can be accounted for when the data are int erpreted utilizing thermodynamic (2nd law) and engineering (in-series efficiency) concepts rather than the heat equivalent of carbohydrate o xidation (20.9 kJ equals one liter of O-2). It is suggested that while oxygen uptake provides an excellent representation of aerobic metabol ism during exercise and recovery, oxygen uptake may be an inadequate m easure of the energetics of lactate production (fermentation). In appl ication, energy expenditure differences appear realistic only for high -intensity, intermittent exercise rather than lower intensity exercise .