Noninvasive methods of determining anaerobic threshold

There are generally three noninvasive methods to determine the AT. (A) Panel A shows the V-slope method, where the AT occurs at the VO₂ at which the slope of VCO₂ versus VO₂ increases. (B) In panel B, AT is determined by the nadir of the VE/VO₂ versus time (or VO₂ on the x-axis). (C) In panel C, AT is determined by the point at which P_ETO₂ increases with increasing work, VO₂, or time.