The purpose of this study was to evaluate the exercise intensities by use of heart rate changes during 5, 10 and 15 min-swims and skill drills. The subjects were 35 female and 5 male varsity students, aged from 19 to 21 years, and performed the swim lessons with crawl stroke. Heart rate responses in 3 male varsity students were measured by means of heart rate memory system, and the exercise intensities was estimated using in terms of HR, % HRmax, and R.P.E.
　The means and SD for velocities during exercises were 8.9±1.0m/min for skill drills, 38.3±7.9m/min, 28.8±8.3m/min, 31.9±7.8m/min for 5, 10 and 15 min swims respectively, In the skill drills at the swim lessons, the means of % HRmax were 48.1-67.5%, and R.P.E. were approximately 13.0 (fairy hard). While in the 5, 10 and 15 min-swims, % HRmax were 82.2%, 85.5%, 88.4% and R.P.E. were 17.0, 17.0, 19.0 respectively.
　However in the 15 min-swim, HRmax, the means of % HRmax and R.P.E. in well-skilled swimmer (183 beats/min, 88.4%, 19.0) coincided with less-skilled swimmer (183 beats/min, 91.9%, 19.0).
　It was suggested that exercise intensities in this swimming program, including the skill drills and 5, 10 and 15 min-swims, might be adequate for improvement aerobic work capacity.

DESCENTE SPORTS SCIENCE Vol.7/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE