Cutaneous vasodilator function plays a role in the thermoregulatory system during rest and exercise, and its dysfunction, especially in elderly people, can influence the system’s vulnerability in heat-stressed conditions. In this review, firstly, we describe the mechanisms that control the cutaneous vasculature in humans. The reflex mechanisms by which sympathetic nerves mediate vasoconstriction and active vasodilation during whole-body thermal stress are examined, including discussions of the mechanisms involving cotransmission, nitric oxide (NO) and other mediators. The mechanisms that effect local cutaneous vasomotor responses to local skin warming are also examined, including the roles of axon reflexes as well as NO and other mediators. Next, we highlight the effects of aerobic exercise training on reflexes and local vasomotor control in the skin. Factors that modulate control mechanisms of the cutaneous vasculature, such as aging and clinical conditions, are discussed. Finally, the beneficial influences of exercise training on cutaneous vasodilator function in healthy young and elderly people with or without chronic diseases are emphasized.

This study was undertaken to clarify the influence of respiratory blood pressure variability upon the relationship between respiratory period and respiratory cardiac cycle variability. In 4 healthy male university students respiratory period was varied over the range of 6-20 sec while tidal volume was maintained constant (21) and in 5 other male students tidal volume was varied over the range of 1.0-2.5l while respiratory period was maintained constant (6 sec) . For cardiac cycle (RR) and systolic and diastolic blood pressure (SBP and DBP), amplitude of respiratory variability and phase difference between respiratory variability and respiration were measured.
1. Patterns of change of amplitude of RR and of SBP were similar when respiratory period was changed.
2. When respiratory period was short (6sec), RR was nearly in phase with SBP. However, as respiratory period increased, the phases of RR and SBP had a tendency to proceed, with the tendency being more pronounced in the latter. Thus, when respiratory period was prolonged (20 sec), SBP led RR.
3. Phase relationship between respiratory SBP variability and respiration did not change when tidal volume was changed.
4. Respiratory DBP variability became more marked as respiratory period increased, and showed more marked phase shift than did respiratory SBP variability. Therefore, of those parameters DBP occurred earlier.
Based on these results, it is concluded that respiratory RR variability is closely related to respiratory SBP variability when respiratory period is changed, but that the phase difference between RR and SBP reflects the effect of pulmonary stretch reflex which is dependent on respiratory period.

A study was conducted to examine the recovery of vagal activity after strenuous exercise based on changes in the magnitude of respiratory cardiac cycle variability, changes in the phase of this variability and the mechanism of the change. Six healthy male university students were studied for 5 h after exhaustive treadmill running. For cardiac cycle (RR) and blood pressure, the magnitude of respiratory variability and phase difference between respira-tory variability and respiration were measured. Respiratory period and tidal volume were maintained at 6 s and 21, respectively.
1. The amplitude of respiratory RR variability decreased markedly after exercise and returned almost to normal after 2 h of recrvery. The phase of RR delayed with exercise, proceeded rapidly 2 h after exercise and progressively after that.
2. The amplitude and phase of respiratory systolic blood pressure variability were almost stable before and after exercise.
Based on these results, we conclude that vagal activity inhibited by strenuous exercise recovers about 2 h after the end of exercise. The delay in the phase of respiratory cardiac cycle variability with exercise may reflect inhibition of vagal activity.

In the present study, we examined cardiovascular response to static and dynamic hand-grip exercise at equivalent work load (peak tension) and tension-time index (TTI, integrated tension for time) in healthy young (n=8) and elderly (n=8) males. Static and dynamic exercises were conducted for 75 s and 150 s at 30% of maximal voluntary contraction (MVC) and for 45 s and 90 s at 50%MVC, respectively. Arterial pressure was continuously measured on a beat basis. Blood pressure at the end of exercise and the magnitude of pressor response induced by exercise did not differ significantly between static and dynamic exercises at the two work loads. The magnitude of pressor response tended to depend on work load. These findings were the same in both age groups. Consequently, it was indicated that blood pressure responses to static and dynamic hand-grip exercise at equivalent work load and TTI did not differ both in young and elderly people. Furthermore, it was suggested that central command and muscle metabolite induced stimulation of the exercise pressor reflex during static and dynamic exercise were similar based on the results of relative perceived exertion and blood pressure response during post-exercise arterial occlusion.

This study was undertaken to clarify the relationship between respiratory period and respiratory arrhythmia. Five healthy male university students voluntarily changed the respiratory period over a range of 3-30 seconds while maintaining tidal volume constant (; 21) . Maximum and minimum cardiac cycles (RRmax and RRmin) and amplitude of cardiac cycle variability (ΔRR), the difference between RRmax and RRmin, were measured from electrocardiogram and respiratory curve.
1. Amplitude of cardiac cycle variability was small for shorter respiratory periods and increased with respiratory period, attaining maximum at respiratory periods of 8-14 seconds followed by decrease at longer respiratory periods.
2. The time from the onset of inspiration to the minimum cardiac cycle was the same for respiratory periods of 8-14 seconds (about 3.6 seconds) .
3. Phase difference between cardiac cycle variability and respiration was determined at each respiratory period. When the minimum or maximum cardiac cycle coincided with the onset of inspiration, this situation being defined as 0°, RRmin was delayed by 180°, 90°, and 0° at respiratory periods of 2.3, 14.4, and 26.5 seconds, respectively and by 360°, 270°, and 180° at respiratory periods of 2.7, 15.0, and 27.3 seconds, respectively.
Based on these results, respiratory arrhythmia is concluded to be quite stable at respiratory periods of 8-14 seconds. At short respiratory periods, tachycardia was found to occur during inspiration and bradycardia during expiration. During long respiratory periods, bradycardia was noted during inspiration and tachycardia during expiration.

To investigate the responses of heart rate and plasma catecholamines to exercise at various intensities, seven healthy adult males performed 6-min bouts of cycling exercise at 30, 50, 70 and 90% of maximal oxygen consumption (VO₂max) . Heart rate (HR), plasma noradrenaline (NA), plasma adrenaline (A), blood lactate (La) and coefficient of variation of R-R intervals (CVRR) were determined i n each case.
The following results were obtained:
1) CVRR showed a sharp decline to the extent of 50%VO₂max, then fell more slightly for heavier exercise.
2) NA and A significantly increased from resting value at 50%VO₂max, and followed by further increase with exercise intensity. NA/A increasd in proportion to exercise intensity.
3) The results of multiple regression analysis of HR (dependent variable) and NA, A and CVRR (independent variables) indicated the greatest standardized partial regression coefficient for CVRR in the case of low intensity exercise, and for NA with high intensity exercise.
4) La increased abruptly at 70%VO₂max, whereas NA and A rose drastically at 90%VO₂max.
The conclusion based on these results is as follows: HR is mainly influenced by change in parasympathetic tone to the extent of 50%VO₂max, whereas sympathetic and adrenomedullary activity are the main factors controlling HR in heavier exercise. Within the submaximal level of exercise, sympathetic activity increases more markedly than that of adrenomedullary activity. Abrupt increase in La may be independent of catecholamines.

A 72-year-old woman, who had been treated for autoimmune hemolytic anemia with prednisolone and azathioprine since 2002, was found to have mild aortic stenosis in 1994. In December 2003, she suffered congestive heart failure, and was on temporary mechanical ventilation. In February 2004, the maximum pressure gradient between left ventricle and aorta increased to 115.8mmHg on echocardiographic examination. On April 6, aortic valve replacement was carried out with a 19mm bioprosthesis (Carpentier-Edwards PERIMOUNT^®, Edwards Lifesciences, Irvine, California). Preoperative prednisolone administration was continued until the day of the operation. Four packs of washed red blood cells were transfused intraoperatively and four packs of red blood cells were transfused postoperatively. Before transfusion, haptoglobin and water-soluble prednisolone were administrated to prevent hemolysis. Oral prednisolone and azathioprine were reestablished on the third postoperative day. Her postoperative course was uneventful and she did not suffer either infection or hemolysis. She was discharged on the 30th postoperative day.

This study compared the hemodynamic performance of the Carpentier-Edwards PERIMOUNT Magna bioprosthesis (Magna) with the Carpentier-Edwards PERIMOUNT bioprosthesis (CEP) for aortic valve stenosis (AS). Between January 2005 and May 2010, 164 patients underwent aortic valve replacement for AS with either the Magna (n=68) or the CEP (n=96) at our institute. Patients undergoing a concomitant mitral valve procedure were excluded from this study. The 21-mm Magna and CEP prostheses were the most frequently used during this period. Transthoracic echocardiography was postoperatively performed within 2 weeks. The peak velocity (PV) of the Magna was significantly lower than that of the CEP (2.59±0.36 vs. 2.75±0.47 m/s ; p=0.022). The mean pressure gradient (PG) was not significantly different. For the 19-mm prostheses, the mean PG and PV of the Magna were significantly lower than those of the CEP [16.4±4.5 vs. 19.7±6.4 mmHg ; p=0.034 (PG) and 2.70±0.36 vs. 3.03±0.49 m/s ; p=0.008 (PV)]. The effective orifice area (EOA) of the Magna was larger than that of the CEP [19 mm : 1.29±0.18 vs. 1.11±0.24 cm² (p=0.007) ; 21 mm : 1.46±0.23 vs. 1.42±0.18 cm² (p=0.370) ; and 23 mm : 1.70±0.34 vs. 1.52±0.25 cm² (p=0.134)]. In this study, the EOA of the Magna was approximately 80% of that described in the manufacture's description. Patient-prosthesis mismatch (PPM ; EOA index≤0.85 cm²/m²) was seen in 26.8% of patients with the Magna and in 47.2% of patients with the CEP (p=0.018). Severe PPM (EOA index≤0.65 cm²/m²) was not seen in any patients with the Magna. The EOA of the 19-mm Magna was significantly larger and the mean PG was lower than those of the 19-mm CEP. Compared with the CEP, the Magna significantly reduced the incidence of PPM, and had superior hemodynamic performance.