In this study, we measured the shape of the face, legs, hands and fingers during the course of a day to determine the amount of swelling. We examined the relationship between the perception of swelling and the degree of actual swelling, and considered the influence of seasonal factors. The topology of the face was measured using the 3D curved shape measuring apparatus, VOXELAN, while the circumference of the legs and fingers and the volume of the hands were also recorded. The measurements were used to determine the amount of change in each parameter, which was then used to determine the degree of swelling. The subjects for the experiment were 10 healthy Japanese women aged 24 to 30 years of standard build (BMI:19.3-25.0). Measurements were carried out twice a day in the mornings and afternoon, first between 8:30 and 10:00 a.m. and then between 4:00 and 5:30 p.m. At each measurement session, subjects were asked if they perceived swelling to have occurred. We investigated the relationship between the degree of actual swelling and the reported perception of swelling. We also investigated the influence of seasonal factors by conducting the same tests on the same subjects in summer (August 1997) and in winter (February-March 1998). The relationship between perceived and actual swelling differs depending on the part of the body. For the face, actual swelling correlates strongly with perceived swelling. This trend is particularly noticeable for the upper eyelids. For the thigh and lower leg, on the other hand, there was no significant difference. The frequency with which subjects reported the perception of swelling varied depending on the area of the body, and was generally extremely low for the thighs, hands and fingers. With respect to seasonal variation, swelling in the face, hands and feet tended to be more pronounced during the summer. In the facial region, the biggest difference was in the lower eyelid, where swelling increased more than five times. This level of variation suggests that the atmospheric temperature is the main factor affecting swelling.
The objective of the present study was to test a hypothesis that a high dietary salt intake potentiates a cold induced increase in blood pressure in normotensive men. Male subjects (n=12) were given 7 g day-1 sodium chloride during the cold months of the year, divided in 3-4 doses per day and dissolved in water, for 14 days additional to their normal diet which contained on the average 9.7 g sodium chloride per day. The same subjects, having their normal diet, served as controls. The resting blood pressure was measured on the fourteenth day seven times at the intervals of five minutes in a climatic chamber in thermoneutral conditions. Then the subjects, wearing a three-layer winter clothing, moved into a wind tunnel (-15°C, air velocity 3.5 ms-1) in which they stayed for fifteen minutes and the blood pressure was recorded at the intervals of three minutes. After the cold exposure, the subjects moved back into the climatic chamber for 30 min and the blood pressure was measured as before the cold exposure. Blood samples were drawn before and after the experiment for ion and hormone measurements. A 12 h urine sample was collected just prior to the cold exposure. A significant difference both in systolic (7 mmHg) and in diastolic (7 mmHg) blood pressure was found between a salt load group and control group under thermoneutral conditions, repeatedly measured over 30 min (paired Student’s t-test; p<0.05). During the whole body cold exposure, blood pressure significantly increased both with and without the extra salt load (repeated measures ANOVA, Student-Newman-Keuls; p<0.05). The level to which the mean arterial pressure increased during the exposure was independent of the salt intake and the profile of the mean arterial pressure curve was similar in both groups. The systolic pressure increased by a 25 mmHg in both groups during the cold exposure. The increase in the diastolic pressure was significantly (paired Student’s t-test, p<0.05) higher in the high salt group (18 ± 4 mmHg) than in the control group (12 ± 3 mmHg) thus supporting partly our hypothesis. After the two-week high salt intake, serum Na+, K+, Cl-, Hct, and plasma Hb were at the similar level as before the extra salt intake. Plasma renin activity, NT-proANP, ANP, and serum aldosterone were not different between the groups, both before and after the cold exposure. The main findings are: 1) the mean arterial pressure increases to the same level and in the same manner independent of the salt load during a short whole body cold exposure and 2) in cold the diastolic blood pressure increases significantly more in people under a very high salt diet.
The objective of this study was to examine changes in sailors’ physical characteristics during three different time periods immediately before the 1996 New Zealand Olympic trials, as a result of a newly introduced sport science programme. Twenty five (19 male and 6 female) Olympic development squad members volunteered as subjects and completed fitness tests at different times between April 1995 and March 1996 after being administered with individualised physical training programmes. Statistically significant improvements were observed in body weight, sum of skinfolds, flexibility (assessed using a sit-reach test), aerobic endurance (assessed using a maximal effort 2500 m rowing test) and strength (assessed as the maximum number of push-ups, pull-ups, and sit-ups that could be completed in 2 minutes) over the three time periods. Thus, physical training was effective in improving many aspects of sailors’ fitness, especially early in the sailing season as a result of pre-season training. Physical performance correlated poorly with both light and heavy wind racing performance. The results suggest that individually tailored training programmes will increase sailing specific fitness. However, it is impossible to know what proportions of racing performance can be attributed to physical fitness, skill, talent, and technology, therefore the effect of physical training on racing performance is difficult to determine.
The purpose of this study was to evaluate the cardiac autonomic control over mental task under various ambient temperatures (21°C, 28°C and 35°C). Seven healthy male subjects engaged in the mental tasks, which consisted of distinctive reaction-time tasks. Respiratory coefficient of variation of instantaneous heart rate (CVRESP), derived from the cross-correlation function between heart rate and respiratory curve, was used as a parameter to assess parasympathetic nervous functions. The difference between total coefficient of variation (CVIHR) and CVRESP was used as a parameter to assess sympathetic nervous functions. The mean heart rate increased at high ambient temperature (35°C) and also during mental task. Both the effects of ambient temperature and task conditions were significant on heart rate, and also on CVIHR. Moreover, the effects of ambient temperature and task conditions in CVIHR were divided into the effect of ambient temperature on CVRESP and the effect of task conditions on the difference between CVIHR and CVRESP. These results implied that respiratory modulated parasympathetic activity might control basal the effect of ambient temperature, and the other components including sympathetic activity contribute to the increase in heart rate due to mental task.
In this study, we used spectral analysis of heart rate variability (HRV) to estimate the changes in autonomic control in response to disparate stimuli produced by mental task and graded head-up tilting. The low frequency (LF) component of HRV provided a quantitative index of the sympathetic and parasympathetic (vagal) activities controlling the heart rate (HR), while the high frequency (HF) component of HRV provided an index of the vagal tone. We studied 17 healthy male subjects (21-25 yr of age) who were placed on a tilt-table and the graded tilt-protocol involved tilted sine angles 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0. These tilt-protocols were repeated with or without the mental task, which consisted of auditory distinctive reaction-time tasks. The basal autonomic mode against the graded head-up tilt was characterized by reciprocal changes in sympathetic and vagal tones. There were significant increases of HR corresponding to the mental task with lower tilt-angle, albeit the changes with higher tilt angles were not significant. Furthermore, there were increases and decreases of the LF component induced by the mental task at lower and higher tilt-angles, respectively. These results revealed that the different responses of HR and LF component against the same tasks could be derived from the alterations of autonomic mode during gradual changes in autonomic control.
Head-out water immersion at thermoneutral temperature (34-35°C) increases cardiac output for a given O2 consumption, leading to a relative hyperperfusion of peripheral tissues. To determine if subjects immersed in water at a colder temperature show similar responses and to explore the significance of the hyperperfusion, cardiovascular functions were investigated (impedance cardiography) on 10 men at rest and while performing exercise on a leg cycle ergometer (ΔM = ~95 W·m-2) in air and in water at 34.5°C and 30°C, respectively. In subjects resting in water, the cardiac output increased by ~50% compared to that in air, mainly due to a rise in stroke volume. The stroke volume change tended to be greater in 30°C water than in 34.5°C water, and this was due to a greater increase in cardiac preload, as indicated by a significantly greater left ventricular end-diastolic volume. Arterial systolic pressure rose slightly during water immersion. Arterial diastolic pressure remained unchanged in 34.5°C water, but it rose in 30°C water. The total peripheral resistance fell 37% in 34.5°C water and 32% in 30°C water. Both in air and in water, mild exercise increased the cardiac output, and this was mainly due to an increase in heart rate. Since, however, the stroke volume increased with water immersion, cardiac output at a given work load appeared to be significantly higher in water than in air. The arterial pressures did not decrease with water immersion, despite a marked reduction in total peripheral resistance. These results suggest that 1) during cold water immersion, peripheral vasoconstriction provides an additional increase in cardiac preload, leading to a further increase in the stroke volume compared to that of the thermoneutral water immersion, 2) the mechanism of cardiovascular adjustment during dynamic exercise is not changed by the persistent increase in cardiac preload in water immersion, and 3) a relatively high cardiac output during water immersion is to maintain a proper arterial pressure in the face of reduced vascular resistance.
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