Subjects were long distance runners (n=6), middle distance runners (n=6), and sprinters (n=4) . They exercised in incremental exercise and steady state exercise. The anaerobic thershold (AT), O₂deficit at AT (AT-O₂df), and time constant of Vo₂ (τ) which were obtained from these exercise tests were compared among three groups of runners, and the interrelationship of three parameters was elucidated. The results were as follows.
1) AT-Vo₂of long distance runners was the highest followed by the values of middle distance runners and sprinters, successively. The AT-Vo₂per weight and per Vo₂max also decreased in the same order.
2) AT-O₂df per weight of long distance runners was as high as that of middle distance runners, and was significantly higher than that of sprinters.
3) τ of long distance runners was shorter than that of middle distance runners, but was not significantly shorter than that of sprinters. τ of long distance runners was shorter than the reported one of untrained people.
4) ΔAT-Vo₂ (difference between AT-Vo₂and Vo₂at rest) related to neither AT-O₂df nor τ. However, the ratio of AT-O₂df/τ significantly related to the ΔAT-Vo₂ (r=0.795, n=16, p<0.001) . From these results, the highest values of AT-Vo₂obtained in long distance runners would be due to both high AT-O₂df and short τ.

The purpose of this study was to determine whether accumulated and temporary fatigue could be separately observed in repeated cycling sprints (RCS) with combined short and long recovery periods. Eight male performed three RCS with 35-sec (RCS₃₅), 350-sec (RCS₃₅₀) and combined 35-sec and 350-sec recovery periods (RCS_comb). RCS_comb consisted of ten 10-sec cycling sprints (CSs) with 35-sec and 350-sec recovery periods before the 5^th and 9^th CS. In RCS_comb, peak power output (PPO) was restored in the 5^th and not in 9^th CS. Blood lactate concentration ([La]) progressively increased, but there were no significant differences among conditions despite the difference in PPO. In RCS_comb, mean power frequency determined on the vastus lateralis was correlated with PPO and oxygen uptake before CSs (preVO₂) showed high in short recovery periods and low values in long recovery periods. Accumulated and temporary fatigue cannot be explained by effects of preVO₂ and [La].

The purpose of this study was to investigate the kinetics of Vco₂during incremental exercise. The subjects were 7 males, age 21-28 years, exercised at two steady state work loads (540 kpm/min, 810 kpm/min) and incremental work load which was increased stepwise by every 1 min from 180 kpm/min to exhaustion. The Vo₂and Vco₂during steady state exercise (4 to 5 min) were determined by the Douglas bag method and arterialized blood samples were taken for lactate (LA) analysis and blood gas analysis. The Vo₂, Vco₂, and blood lactate were also determined throughout the incremental exercise. At exhaustion, mixed venous Pco₂ (PVco₂) was determined by the CO₂rebreathing method.
1) The Vco₂values at rest and during steady state exercise were linearly related to the Vo₂values. When the regression line was compared with Vco₂during the incremental exercise on the same Vo₂, the Vco₂during the incremental exercise below the anaerobic threshold showed lower values.
2) The total sum of the difference in Vco₂between steady state and incremental exercise was defined as CO₂store. The calculated CO₂store and CO₂store per body weight were significantly related to PVco₂at exhaustion in incremental exercise, respectively (r=0.954, r=0.954) .
3) At work load below the anaerobic threshold, Vco₂was linearly related to Vo₂. If the Vco₂above the anaerobic threshold is estimated from Vo₂using the regression line obtained at work load below the anaerobic threshold, the estimated Vco₂will be lower than the measured Vco₂. The total sum of the difference in the Vco₂was defined as CO₂excess. The CO₂excess and the CO₂excess per body weight were significantly related to ΔLAmax (the difference between LA at 3rd min after exhastion and LA at exercise below the anaerobic threshold), respectively (r=0.870, r=0.930) .
4) HCO₃^-calculated from blood gases (pH and Pco₂) was significantly related to LA (r=-0.902) . The increase of 1 mM/1 in LA was corresponding to the decrease of 0.843 mEq/l in HCO₃^-.
5) From these results, it appeared that the expired Vco₂during the incremental exercise consisted of the stored Vco₂, the exceeded Vco₂, and the produced Vco₂ (Vco₂metabolically produced from Vo₂) .

In order to elucidate the changes of cardiovascular functions on the long distance running in middle-aged and old men (aged 40-87 years) performing the running training at least over a year measured on blood pressure and ECG before and after the 10km, 25km and 42km running, respectively. Furthermore, several runners fainted during and at the end of running were also measured on the blood pressure at the fainting. The results were summarized as follows,
In the 10km, 25km and 42km running the average values of systolic (excepting the 10km), and diastolic pressure after running were significantly lower than those average values before running. Further, it was noted that the higher the systolic and diastolic pressure before running were the more the reduction of those blood pressure after running in any distance, and also with the prolongation of running distance the reduction of those blood pressure became more remarkable. Especially, the reduction of blood pressure in the fainted runners was very remarkable. On the other hand, the pulse pressure showed no significant difference between before and after running.
On the observation of ECG recorded before and after running, the shortening of PQ interval and the prolongation of QTc were noted after running, especially the prolongation of QTc in a group of 42km was remarkable. While the reduction of T_II voltage was also found after running.
It may be therefore thought that a long distance running in middle-aged and old men bring on large changes for their cardiovascular functions, even if they continued the running training over a year.

Preliminary studies on the blood composition were carried out with 40- to 82-year-old runners when they were at rest. 790 male subjects who had kept the routine training of running over a year were examined. And the results were compared those with the corresponding control groups who had no particular routine training.
The results were as follows:
1. Runners' values for Red blood cell count and Hematocrit were decreased with age.
2. Runners' values for Red blood cell count, Hemoglobin and Hematocrit were approximately 10%, 9% and 4% lower than those of the corresponding control groups of almost all age groups. On the other hand runners' values for MCH (Mean Corpuscular Hemoglobin) were approximately 8% higher than the control group values for all age groups.
3. Runners' values for reticulocyte count and osmotic fragility of the blood were within normal range.
4. Comparison between runners of 10 km group and 25 km group of blood composition was made; the age group of forties of 25 km group of both Red blood cell count and Hematocrit were significantly lower than the corresponding 10 km group.
5. Dailly training programs of 25 km runners were significantly longer than those of 10 km runners for all age groups.

Physiological characteristics of middle-aged and old runners, who competed in the international 10km or 25 km race, were investigated. All of 2260 runners were aged 40 to 86 years. They have been trained for at least one years. Body composition, resting blood pressure, blood composition, serum metabolites, serum enzymes and pulmonary function were measured. The runners who competed in 10 km race were compared with those competed in 25 km race. Relation between running performance and physioloigical parameters were discussed.
1) Average running speed was faster in 25 km group than in 10 km group, although 25 km group ran a longer distance. In daily training, 25 km group also showed longer running distance than in 10 km group.
2) Body weight averaged 55.9±6.82 kg in a whole group of 2260 runners. Skinfold thickness averaged 6.1±2.50 mm in triceps, and 10.9±3.78 mm in subscuplar. These values were remarkably lower than normal values of corresponding age of the Japanese. 25 km group showed significantly lower values in these parameters than 10 km group. The runner who made better performance also showed lower values in these parameters.
3) Resting blood pressure of the runners averaged 144.3±17.0 mmHg in systole, and 86.2±11.0 mmHg in diastole. No difference were found between 10 km group and 25 km group in blood pressure.
4) RBC, Ht, Hb of 645 runners averaged 411.8±37.4×10⁴/mm³, 40.3±3.70%, 14.5 ±1.25g/dl, respectively. These values were lower than in normals. Among age group of 40-49yrs, negative correlation between running speed and these heamatological parameters were found. Better runner showed lower values in these parameters.
5) Blood glucose, serum choresterol, LDH and CPK were not different from normal values.
6) Pulmonary function were not different from normal values. Remarkable decrease with increasing age were found in pulmonary function.

The purpose of this study was to investigate the changes of blood components of middle and old aged runners in marathon running. The results were as follows.
1) Mean running time of marathon was 250 min. Some of subjects did last spurt.
2) Change of body weight was -4.8%. RBC, Hct, and Hb were changed by -4.8%, -4.4%, and -4.7% respectively. The decrease of plasma volume was 7.8% according to Dill's method.
3) Blood glucose was 112 mg/dl at rest and decreased to 70 mg/dl after running. The glucose level of five subjects was in range from 59 to 50 mg/dl.
4) The increase of L.A. was 52%. The L.A. after running tended to correlate to the running speed at last spurt.
5) T.G. significantly decreased after running. On the contrast, FFA increased by 323%. This increment of FFA correlated to mean running speed (r=0.681, P<0.05) .
6) The increments of GOT, GPT, and LDH were 71%, 62%, and 61% respectively, The decreases of LDH-1, 2 and increases of LDH-4, 5 were found after running. Furthermore, AGOT and 4GPT correlated to the running speed at last spurt or L.A. after running.