The rate of peripheral circulatory adjustment at the onset of exercise was studied in six active women aged 2022 yrs. Five bouts of exercise with different duration of 15, 30, 60, 120 and 180 s were performed on a level treadmill at an intensity of 70% Vo₂max. Calf blood flow was measured with a mercury-in-rubber strain gauge plethysmograph immediately after cessation of each bout of exercise. Heart rate and Vo₂ were measured during running.
Calf blood flow after 15-s exercise increased to 25.98±3.51 ml/100 ml/min (mean±SD), which corresponded to 70% of the mean calf blood flow (32.80 ml/100 ml/min) immediately after 180-s exercise. The relative increases in calf blood flow after 15- and 30-s exercise were significantly higher than those of heart rate. The Vo₂ after exercise of identical duration showed a smaller percentage increase in comparison with heart rate.
The increase of calf blood flow or heart rate was fitted best by a monoexponential equation, Yt=C-ae^-kt, where Yt is the response at time t (s) expressed as a percentage of the value at 180-s exercise, C is 100 in the present study, and k is a rate constant. The rate constant k in the equations ranged from 0.025 to 0.179 for blood flow and 0.025 to 0.036 for the heart rate. The calculated half-times (t1/2) for the increase in blood flow averaged 12.85 s, ranging from 5.6 to 20.0 s. This was significantly (p<0.05) shorter than HRt 1/2, which averaged 21.7 s.
The present study therefore showed that the adjustment of the peripheral circulatory system at the commencement of treadmill runnning at an intensity of 70% Vo₂max preceded the central circulatory adjustment.

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Physical fitness of 900 volunteers over 60 years of age were analyzed using a 6-item battery test to obtain fundamental data on the fitness status of the aged Japanese. The test battery consisted of stepping, vertical jump, grip strength, breath holding, body flexion and one-leg balancing, and could be performed safely with relatively mild physical stress in the elderly after simple screening by measurement of resting blood pressure and oral check on mobility problems of the knee and the hip. Males showed significantly higher values in vertical jump, grip strength and breath holding, while females showed significantly higher values in body flexion. There were no sex differences in stepping and one-leg balancing. Lowing trend was found in the score with age in all items except breath holding, but the extent of the reduction differed among the measure elements of fitness. Most of measured items showed significant correlations each other. The values obtained with this test are considered to be useful for future analysis of the fitness of aged people and also to determine the exercise appropriate for them.

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Stature, body weight, grip strength, back strength and Sargent jump of city dwellers, covering an age range from children to elderly subjects, were measured in order to study the development and aging of physical fitness.
From these cross-sectional data, growth and aging curves were obtained.
Stature appeared to decrease gradually in adulthood but a secular increasing trend was included in the data, so that in fact hardly any change is notable except in late adulthood.
Body weight seemed to increase to some degree in middle adulthood after secular trends had been removed from the data.
The data for back strength showed more rapid decrease in adulthood, infering that the strength of back muscles decreases in adulthood, though there have been insufficient reports on secular trends of muscle strength. Leg power decreased gradually in a similar way after development during adolescence. Grip strength seemed to change little or increase only slightly in middle adulthood, and to decrease later.
Cross-sectional data contain more secular trends than age-related changes in physique during adulthood. The present data may show roughly some growth patterns at certain ages when the rate of growth and development is high and aging patterns at ages when the decrease in fitness is marked. However, details on personal growth and aging patterns should be studied by the longitudinal method.

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Maximal oxygen uptake (Vo₂max) and lactate threshold were measured during an incremental bicycle ergometer test in 40 healthy middle-aged and older runners between 43 and 79 years of age. Although the 10-km run time slowed with increasing age, there were no significant differences in recent training habits or relative amount of body fat between four age groups. However, our cross-sectional data revealed an annual decrement of -0.74 ml/kg/ min/yr, which was significantly greater than that reported in previous studies. Vo₂max values for the runners were greater than those for sedentary men of similar ages by about 50% in each age group. Significant correlations were found between the age at the onset of running training and Vo₂max (r=-0.600, p<0.05) . Vo₂@LT declined significantly but less rapidly with age (r=0.686, p<0.05) than Vo₂max. Both the mean maximal heart rate (HRmax) and HR@LT also declined with age. No significant differences in HRmax were observed between the runners and sedentary men of the respective age groups. Significant correlations were also found between the estimated HRmax and directly measured HRmax (r=0.600) . Neither systolic blood pressure nor diastolic blood pressure during submaximal-maximal exercise were found to increase with age. We suggest that maintenance of a higher lactate threshold in older runners when expressed as a percentage of Vo₂max is attributable to a greater age-dependent decline in Vo₂max with a smaller change in Vo₂@LT.

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Spectral analysis was applied to investigate whether the system for control of heart rate (HR) is influenced by exercise intensity. Five healthy males performed incremental exercise on an electrically braked cycle ergometer until exhaustion. The work rate was increased at 12 W/min following 2 min of exercise at a constant load of 20 W. HR was measured every second from R-R intervals. The power spectrum was calculated every 10 s using the FFT method for 64 consecutive data points. Power spectra during 20 W exercise showed a similar pattern to those in previous reports on resting HR perturbations, Although interindividual differences were observed for the spectrum patterns related to exercise intensity, there was a characteristic pattern revealing dissipation of the spectral power above a frequency of 0.2 Hz for all subjects. This pattern was not maintained for more than 1 min in any of the subjects, and was followed by a semirandom pattern whose magnitude varied among the subjects. These results support the hypothesis that the cardiac pacemaker is influenced by exercise intensity, presumably due to sympatho-vagal interaction with the respiratory control system.

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