Figure 3

Dynamic responses of ATP and NADH concentrations during a 10-min moderate intensity exercise period (WR = 65W) of a sedentary individual. The left y-axis corresponds to changes in [ATP] while the right y-axis indicates the changes in [NADH]. Steady state responses are present from time -5 min to time 0 min when the step change in work rate (WR) is initiated. The solid and dashed lines represent the model simulation results with the symbols representing experimental data points [mean ± SD] [60,69]. [ATP] remains fairly constant while [NADH] drops 40% during exercise.