A common protocol to evaulate endurance athletes is a two-step lactate profile-VO2max test. A typical procedure provides 20–30 min rest between profile and max. The effect of the profile and/or the rest period on the subsequent VO2max value is not known. PURPOSE: To examine effects of preceding high intensity submaximal exercise, with or without rest, on a subsequent rapid ramp VO2max test. METHODS: Ten endurance-trained males completed three separate exercise trails: an incremental run to fatigue (MAX), a continuous lactate profile-VO2max test (C), and a discontinuous lactate profile-VO2max test (DC). Protocol for C and DC were identical except for a 20-minute rest period between the lactate profile and VO2max test during DC. All trials were separated by 24 hours. MAX was always completed first; C and DC were randomized between the second and third day. RESULTS: No differences in VO2max between trials were evident (MAX = 62.67 ml/kg/min, C = 61.20 ml/kg/min, DC = 58.29 ml/kg/min; p = .059). Subjects with a ± 7.5% fall in VO2max from MAX (Responders) were compared to those with < 7.5% fall (Non-Responders). DC Responders (n = 5) had higher VO2max during MAX than DC Non-Responders (n = 5) (Responders = 67.64 ml/kg/min, Non-Responders = 57.70 ml/kg/min; p = .008). C Responders (n = 2) achieved a VO2max of 71.05 ml/kg/min during MAX; C Non-Responders (n = 8) achieved a VO2max of 60.58 ml/kg/min during MAX. CONCLUSIONS: The trend for lower DC VO2max values, coupled with the DC Responder results, suggests a reduction in VO2max in some athletes if maximal exercise is preceded by high intensity submaximal exercise and a rest period. The effects of preceding high intensity exercise without rest on the achievement of VO2max are still unclear. Supported by the United States Olympic Committee.