A recent bout of high-intensity exercise can alter the balance of aerobic and anaerobic energy provision during subsequent exercise above the lactate threshold (_L). However, it remains uncertain whether such "priming" influences the tolerable duration of subsequent exercise through changes in the parameters of aerobic function (e.g. _L, maximum oxygen uptake; VO_2max) and/or the hyperbolic power-duration (P-t) relationship (critical power (CP) and the curvature constant (W')). We therefore studied six males performing cycle-ergometry to the limit of tolerance; gas exchange was measured breath-by-breath and arterialized-capillary blood [lactate] at designated intervals. On different days, each subject completed (a) an incremental test (15 W.min^-1) for estimation of _L and measurement of the functional gain (VO₂/WR) and VO_2peak; and (b) 4 constant-load tests at different work rates (WR) for estimation of CP, W' and VO_2max. All tests were subsequently repeated with a preceding 6-min supra-CP priming bout and an intervening 2-min 20 W recovery. The hyperbolicity of the P-t relationship was retained post-priming, with no significant difference in CP (241±39 vs. 242±36 W, post- vs. pre-priming), VO_2max (3.97±0.34 vs. 3.93±0.38 l.min^-1), VO₂/WR (10.7±0.3 vs. 11.1±0.4 ml.min^-1.W^-1), or the fundamental VO₂ time constant (25.6±3.5 vs. 28.3±5.4 s). W' (10.61±2.07 vs. 16.13±2.33 kJ) and the tolerable duration of supra-CP exercise (-33±11%) were each significantly reduced, despite a less prominent VO₂ slow component. These results suggest that, following supra-CP priming, there is either a reduced depletable energy resource or a residual fatigue-metabolite level that leads to the tolerable limit before this resource is fully depleted.