The use of 60%-95% of maximal heart rate (HR), heart rate reserve (HRR) and VO2max as exercise training intensities was examined in male runners, and these intensities were related to VO2 observed at the lactate threshold (LT) and fixed blood lactate concentrations (FBLC) of 2.0, 2.5, and 4.0 mM. Thirty-one subjects (means age = 29.9 +/- 9.1 yrs; means ht = 177.3 +/- 8.2 cm; means wt = 69.2 +/- 9.9 kg) completed a level running treadmill protocol. The mean values at LT, FBLC of 2.0, 2.5, 4.0 mM and max for VO2 were 52.7, 56.4, 58.0, 61.2 and 63.5 ml/kg.min -1, respectively: for velocity they were 237.4, 252.2, 260.6, 274.4 and 286.5 m/min, respectively; and for HR were 165.7, 172.7, 176.5, 182.3 and 187.4 bts/min, respectively. The majority of subjects were not above LT (N = 20), until an intensity of 90% HR max was attained. At 95% HR max the majority of subjects were above 2.0 mM (N = 23) and 2.5 mM (N = 17) but below 4.0 mM (N = 26). For HRR, 85% HRR was necessary for the majority of subjects to be above LT (N = 20), 90% HRR resulted in the majority of subjects being above 2.0 mM (N = 19), while 95% HRR was required for the majority of subjects to be above 2.5 mM (N = 23). At 95% HRR 14 subjects were above 4.0 mM. For % VO2max, the intensities required for the majority of subjects to be above LT, FBLC of 2.0, and 2.5 mM were 90%, 95% and 95% VO2max, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)