Fourteen young males (mean age 26.7 yrs) were tested to determine if there was an alteration, in the heart rate-oxygen uptake relationship during submaximal cycle ergometer exercise following isokinetic strength training activity as has been documented following high intensity endurance activity. Results indicated that there was a significant increase rate without a concomitant increase in heart oxygen uptake during the first five minutes of submaximal cycle riding at 73% VO2max after heavy strength leg exercise, angular velocity of 30 degrees/second, when compared to no prior exercise. This alteration in the heart rate-oxygen uptake relation is not apparent by 20 minutes of the same submaximal exercise despite higher lactate values and greater ratings of perceived exertion. For individuals using heart rate as a guide to exercise intensity, the elevated heart rate at five minutes of submaximal exercise following heavy strength leg exercise does not exceed the 20 minute value which is an accurate reflection of energy cost and intensity.