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.

The early and mid-term survival after thoracic aortic surgery and the influence of age on operative mortality were examined in 93 consecutive patients from August 1994 to June 1999, together with assessment of postoperative quality of life (QOL). The mean age was 63.8±11.6 years old (range 26 to 84 years) and 65 patients were male. Aneurysms were atherosclerotic in 43 patients and aortic dissection was present in 50. Forty-eight (52%) required emergency operation. Operative procedures consisted of ascending aorta or hemiarch replacement in 23 patients, Bentall's operation was performed in 4, total arch replacement in 31, distal arch replacement in 9, descending aorta replacement in 13, replacement of the thoracoabdominal aorta in 6, and patch repair in 7. These patients were divided into two groups: the under 70 group (Y group, n=61) and the 70 or older group (O group, n=32). Current QOL of the survivors was assessed using the Asanoi method with a mailed questionnaire. There were 13 early deaths (14%). There were 10 late deaths (5.6%/P-Y (Patients-Years)). The actuarial survival rate of the Y group was significantly higher than that of the O group (p=0.0412). Perioperative stroke was seen in 11% of the Y group and 16% of the O group. These patients had a high mortality rate (Y group 43%, O group 100%) during early and long term follow-up periods. The postoperative NYHA category and exercise ability of the O group were better than those of the Y group. We obtained satisfactory answers concerning the results of operation in the majority of current survivors. Patients aged 70 years and older could undergo thoracic aortic surgery with reasonable risk. QOL following operation was satisfactory except in patients with merged perioperative stroke.

Physical training has been shown to improve glucose tolerance and insulin action in peripheral tissues. In the present study, regular (R) and high (H) -dose euglycemic clamp procedures were performed to determine the effects of different types of physical training on insulin action (sensitivity/responsiveness) in 10 long-distance runners (LR), 10 weight-lifters (WL) and 12 healthy controls (HC), The amount of infused glucose (glucose metabolism, GM) during euglycemic clamping is a measure of the peripheral tissue sensitivity and/or responsiveness to insulin. For R clamping, when GM was calculated per unit body weight (BW), GM in LR (11.92±1.22 mg/kg BW·min) and WL (9.28±0.63 mg/kg BW·min) was significantly (P<0.05) higher than that in HC (7.44±0.39 mg/kg BW·min) . When calculated per unit lean body mass (LBM), LR (15.07±1.56 mg/kg LBM·min) differed from HC (9, 15±0.59 mg/kg LBM·min, P<0.05), whereas the value in WL (11.50±0.93mg/kg LBM·min) was identical to that in HC. For H clamping, there was no significant change in these three groups when GM was calculated per unit BW or LBM. These results suggest that enhancement of insulin action by physical training is due to an increase in insulin sensitivity, rather than to an increase in insulin responsiveness, and that aerobic exercise, for example long-distance running, is more effective for the improvement of decreased sensitivity to insulin, which is observed in patients with simple obesity and diabetes, than anaerobic exercise such as weight-lifting.

The purpose of this study was to compare the effect between cyclists and noncyclists of pedal rates on ankle, knee, and hip joint torque during pedaling exercises. Six male cyclists (CY) and seven male noncyclists (NC) pedaled at 40, 60, 90 and 120 rpm with a power output of 200 W. The lower limb was modeled as three rigid segment links constrained to plane motion. Based on the Newton-Euler method, the equation for each segment was constructed and solved on a computer using pedal force, pedal, crank, and lower limb position data to calculate torque at the ankle, knee, and hip joints. The average planter flexor torque decreased with increasing pedal rates in both groups. The average knee extensor torque for CY decreased up to 90 rpm, and then leveled off at 120 rpm. These results were similar to NC. The average knee flexor torque in both groups remained steady over all pedal rates. The average hip extensor torque for CY decreased significantly up to 90 rpm where it showed the lowest value, but increased at 120 rpm. For NC, the average hip extensor torque did not decrease at 90 rpm compared with 60 rpm, and was significantly higher than CY at 120 rpm (CY : 28.1 ± 9.0 Nm, NC : 38.6 ± 6.7 Nm, p<0.05) . The average hip flexsor torque for NC at 120 rpm increased significanly from 90 rpm, and was significantly higher than CY (CY : 11.6±2.9 Nm, NC : 22.6±11.8 Nm, p<0.05) . These results suggest that it would be better for cyclists to select a pedal rate of between 90 to 110 rpm to minimize joint torque, and, as a result, reduce peripheral muscle fatigue.

Seven patients with hemiplegia due to cerebral apoplexy and 5 subjects without any sign of cardiovascular abnormalities (as the contol cases) were used in this study. Systemic blood pressure by sphygmomanometer, digital blood pressure and digital blood flow by digital plethysmograph were recorded and the peripheral vascular resistance was calculated from the values. The extensibility of arterial wall was calculated from transmission time of the pulse wave and length of the vessel. The effect of bathing therapy in hot spring water (sodium sulphate spring; bathing temperature ranging from 41-43C; bathing duration ad libitum) on the peripheral vascular hemodynamics was examined.
1. Effects of single bathing
In patients with hemiplegia, systolic blood pressure decreased 40mm Hg in the paralyzed, but slightly in the unparalyzed side, and also the decrease of digital blood pressure was greater in the former than in the latter. Digital blood flow increased and the peripheral vascular resistance decreased in both sides, and the rate of change was much greater in the paralyzed than in the unparalyzed side, respectively.
In the control cases, the changes were fairly comparable to those in the unparalyzed side of the patients except the extensibility of the arterial wall which was manifest in both sides of the patients but only scarce in the control subjects.
2. Effects of repeated bathing
In patients with hemiplegia who had taken the bathing therapy for 30-90 days, the digital blood flow increased and the paripheral vascular resistance decreased but without noticeable differences between the paralyzed and the unparalyzed side, and the size of the increase or the decrease was almost equal to that in the control subjects. Increase in the extensibility of arterial wall was found more in the patients than in the controls. In general the effects of repeated bathing were less distinguished than those of single bathing.

Periodontal tissue has a unique structure in that the human periodontal ligament (hPDL) lies between the hard tissues of cementum and alveolar bone. Although the role of cytokines in hPDL function is not clearly understood, we investigated the effect of mechanical stress as hydrostatic pressure (HP) on cytokine expression in hPDL cells.The hPDL cells were obtained from a healthy maxillary third molar. After the 3rd to 4th passage, the cells were exposed to HP ranging from 1 MPa to 6 MPa as previously described. The expression of cytokine mRNA was determined by RT-PCR and cytokines in the culture supernatants were assessed by enzyme-linked immunosorbent assay (ELISA).The exposure to 6 MPa of HP caused no morphological changes of hPDL cells, and did not affect cellular viability. No expression of IL-1β, IL-6, IL-8, TNF-α, RANK, RANKL or OPG mRNA was observed in the control cells under atmospheric pressure, whereas in hPDL cells treated with HP, enhancement of IL-6, IL-8, RANKL and OPG mRNA expression was observed between 10 and 60 minutes after the exposure to HP. After the exposure to HP, the production of IL-6 and TNF-α were induced significantly in hPDL cells, but IL-1β and IL-8 were not produced.These results suggest that hPDL cells may play a role in the production of cytokines in response to mechanical stress in vivo.

The purpose of this study was to compare effects of different amounts of carbohydrate (CHO) in beverage on plasma glucose (GLU) concentration during exercise after feeding breakfast. Seven healthy Japanese male subjects performed 30-min cycling at an intensity on the 75% of maximal load at 3-h after feeding breakfast under 3 types of CHO (0 g, 30 g and 150 g) beverage conditions. The subjects ingested 500 mL of beverage dissolved each amount of glucose at 30-min before the exercise. The GLU concentrations were measured at 35- and 10-min before the exercise and every 5-min during the exercise. The minimum GLU concentrations under the 30 g condition for all subjects were lower than a criterion for hypoglycemic (72 mg / dL). The mean value also fell below the criterion at from 10- to 20-min during exercise. The minimum GLU concentration under the 150 g condition of only one subject was lower than the criterion, but the mean value did not fall below the criterion. Significant negative correlations were found between the subjects’ maximum oxygen uptake (VO2max) and the decreases in GLU concentration from maximum to minimum under both the 30 g (r = -0.947, p < 0.01) and 150 g conditions (r = -0.884, p < 0.01). This study clarified that feeding breakfast at 3-h before the exercise followed by the 30 g CHO beverage ingestion at 30 min before the exercise induced exercise-induced hypoglycemia, and that the subjects with higher VO2max had the greater decreases in GLU concentration.