[Ventilatory threshold in Japanese--as the basis for exercise prescription for health promotion]

Oxygen consumption (VO2) at ventilatory threshold (VT) was measured in 610 healthy Japanese with differing ages (305 men: 45.1 +/- 15.8 years; 305 women: 44.3 +/- 16.0 years) to develop a scale for exercise prescription with the ultimate purpose of health promotion. Ramp exercise test using a bicycle ergometer was used as an exercise loading test. VT was determined using the breath by breath method. Standard aerobic capacity was determined according to age and sex using VT as the indicator. 1) VO2 at VT(Y) decreased with age (X), and closely approximated a single regression formula, Y = 22.4-0.16X (r = -0.626, p < 0.001) for men and Y = 18.1-0.10X (r = -0.578, p < 0.001) for women. 2) There was a sex difference in VT being significantly (p < 0.01) higher in men than in women. 3) The work rate (WR) at VT was also significantly higher in men. 4) There was no sex difference in heart rate (HR) at VT; 115 beats/min. in subjects in their 30 s, 110 beats/min. in those in their 40 s, 105 beats/min. in those in their 50 s, and 100 beats/min. in those in their 60 s. 5) Rating of perceived exertion (RPE) at VT was not influenced by age or sex differences, and was about 13. 6) The minimum level of VT, at which daily living activities was possible was about 3 METs. 7) There was a significant positive correlation between mean number of steps per day and VT. VO2, HR and WR at VT decreased with age although there was no sex difference in HR, and there was no age or sex difference in RPE. These results suggest that health promoting exercise can be prescribed on the basis of HR which would be identical figures for men and women of the same age, and also by RPE specified as less than "somewhat hard".