Effects of Defecation Strain at Various Bed Reclining Angles on Intrarectal Pressure and Cardiovascular Responses.

BACKGROUND: There is no clear information about the optimal bed reclining angle for promoting efficient and safe defecation in bedfast patients. OBJECTIVE: The aim of this study was to examine the optimal bed reclining angle for facilitating increases in intrarectal pressure without causing marked cardiovascular changes in order to develop an efficient and safe defecation position for bedfast patients. METHODS: Twelve healthy men participated in this study. The subjects were required to strain for 15 seconds at the end stage of inspiration while their bed was reclined at 0° (supine), 15°, 30°, or 60°. During straining, the subjects were asked to maintain (a) an intrarectal pressure of 20 mm Hg or (b) the maximal intrarectal pressure. Intrarectal pressure, blood pressure, heart rate, and abdominal muscle activity (electromyographic activity) were recorded continuously throughout the study period. RESULTS: During straining, intrarectal pressure increased with the reclining angle, and a significant linear correlation was detected between the sine of the reclining angle of the bed and intrarectal pressure (η = .57, p < .01). When subjects were straining with the aim of maintaining maximal intrarectal pressure, the extent of the observed changes (delta) in blood pressure and heart rate did not differ significantly across the reclining angles. When subjects were straining with the aim of maintaining an intrarectal pressure of 20 mm Hg, the delta blood pressure decreased as the reclining angle increased 0°: M = 23.7, SD = 15.3 mm Hg, 95% CI [11.9, 35.4]; 15°: M = 25.9, SD = 10.8 mm Hg, 95% CI [17.6, 34.2]; 30°: M = 17.7, SD = 9.4 mm Hg, 95% CI [10.4, 24.9]; 60°: M = 15.5, SD = 9.5 mm Hg, 95% CI [8.1, 22.8]; 15° versus 30°: p < .05; 15° versus 60°: p < .05. The amount of muscle activity observed during straining decreased as the reclining angle increased. DISCUSSION: In bedfast patients, it is suggested that higher reclining angles may enable safer and more efficient defecation, because it decreases the amount of muscle activity required to increase the intrarectal pressure and reduces the potentially deleterious effects of straining on the cardiovascular system to develop an efficient and safe defecation position for bedfast patients.

Effects of isotonic and isometric exercises with mist sauna bathing on cardiovascular, thermoregulatory, and metabolic functions.

To clarify the effects of isometric and isotonic exercise during mist sauna bathing on the cardiovascular function, thermoregulatory function, and metabolism, six healthy young men (22 ± 1 years old, height 173 ± 4 cm, weight 65.0 ± 5.0 kg) were exposed to a mist sauna for 10 min at a temperature of 40 °C, and relative humidity of 100 % while performing or not performing ∼30 W of isometric or isotonic exercise. The effect of the exercise was assessed by measuring tympanic temperature, heart rate, systolic and diastolic blood pressure, chest sweat rate, chest skin blood flow, and plasma catecholamine and cortisol, glucose, lactate, and free fatty acid levels. Repeated measures ANOVA showed no significant differences in blood pressure, skin blood flow, sweat rate, and total amount of sweating. Tympanic temperature increased more during isotonic exercise, and heart rate increase was more marked during isotonic exercise. The changes in lactate indicated that fatigue was not very great during isometric exercise. The glucose level indicated greater energy expenditure during isometric exercise. The free fatty acid and catecholamine levels indicated that isometric exercise did not result in very great energy expenditure and stress, respectively. The results for isotonic exercise of a decrease in lactate level and an increase in plasma free fatty acid level indicated that fatigue and energy expenditure were rather large while the perceived stress was comparatively low. We concluded that isotonic exercise may be a more desirable form of exercise during mist sauna bathing given the changes in glucose and free fatty acid levels.

A comparison of head-out mist bathing, with or without facial fanning, with head-out half-body low-water level bathing in humans--a pilot study.

To reduce the risks of Japanese-style bathing, half-body bathing (HBLB) has been recommended in Japan, but discomfort due to the cold environment in winter prevents its widespread adoption. The development of the mist sauna, which causes a gradual core temperature rise with sufficient thermal comfort, has reduced the demerits of HBLB. We examined head-out 42 °C mist bathing with 38 °C HBLB up to the navel to see if it could improve thermal comfort without detracting from the merits of HBLB, with and without the effects of facial fanning (FF). The subjects were seven healthy males aged 22-25 years. The following bathing styles were provided: (1) HBLB-head-out half-body low bathing of 38 °C up to the navel (20 min); (2) HOMB-head-out mist bathing of 42 °C and HBLB of 38 °C (20 min); and (3) HOMBFF-HOMB with FF (20 min). HOMB raised the core temperature gradually. HOMBFF suppressed the core temperature rise in a similar fashion to HOMB. Increases in blood pressure and heart rate usually observed in Japanese traditional-style bathing were less marked in HOMBs with no significant difference with and without FF. The greatest body weight loss was observed after Japanese traditional-style bathing, with only one-third of this amount lost after mist bathing, and one-sixth after HBLB. HOMB increased thermal sensation, and FF also enhanced post-bathing invigoration. We conclude that HOMB reduces the risks of Japanese traditional style bathing by mitigating marked changes in the core temperature and hemodynamics, and FF provides thermal comfort and invigoration.

Effects of catechin-enriched ion beverage intake on thermoregulatory function in a hot environment.

We examined the effect of intake of a catechin-enriched ion beverage (Cat-I) on the thermoregulatory response in a hot environment. Eight healthy men were exposed to a hot environment for 90 min at an ambient temperature of 35 °C (relative humidity: 75%) combined with lower leg water immersion at 40 °C. At that time, either Cat-I, an ion beverage (Ion), or mineral water (Placebo) was consumed at three points: (1) at the start of lower leg immersion, (2) at 30 min after immersion, and (3) at 60 min after immersion. In all conditions, tympanic temperature (Tty) increased gradually during lower leg water immersion. However, the rate of increase of Tty tended to be suppressed after 30 min. The effect of drinking Cat-I had a limited detection period of approximately 60-70 min, and the rate of sweating was clearly increased with Cat-I compared with Ion and Placebo. Cat-I also tended to decrease the body temperature threshold at which sweating was induced compared with Ion or Placebo. These findings suggest that Cat-I efficiently suppressed the increase of body temperature in a hot environment.