Energy replacement diminishes the postprandial triglyceride-lowering effect from accumulated walking in older women

[Purpose] Dietary replacement of an acute exercise-induced energy deficit offsets the postprandial triglyceride (TG)-lowering effect of exercise in young boys and middle-aged men. It is unclear whether these findings are observed when exercise is accumulated in older adults. This study examined the effect of accumulating short bouts of exercise, with and without dietary replacement of an exercise-induced energy deficit, on postprandial TG in older women. [Methods] Seventeen older women (≥ 65 years) underwent three, 8-h trials: 1) control, 2) accumulated walking and 3) accumulated walking with energy replacement. During the control trial, participants rested for 8 h. The accumulated walking trials comprised twenty 1.5 min brisk walking bouts performed at a pre-determined self-selected pace separated by 15 min seated rest. In each trial, participants consumed a standardised breakfast and lunch. The breakfast in the accumulated walking with energy replacement trial included replacement of the energy deficit (0.62 MJ, 149 kcal) induced by exercise. Venous blood samples were collected fasted and at 2, 4, 6 and 8 h after breakfast. [Results] Time-averaged postprandial serum TG concentrations over 8 hours were lower after accumulated walking than control and accumulated walking with energy replacement (mean ± SD: 1.46 ± 0.93 vs 1.71 ± 1.01 vs 1.60 ± 0.98 mmol/L respectively: main effect of trial p = 0.017). There was little difference between control and accumulated walking with energy replacement. [Conclusions] Replacing the energy expenditure induced by accumulating 30 min of brisk walking in short (1.5 min) bouts diminishes the postprandial TG-lowering effect in older women.