Usefulness of R-R interval and its variability in evaluation of thermal comfort

Hasebe, Yae; Iriki, Masami; Takahasi, Kazuko

doi:10.1007/bf01208486

Cited by 19 publications

(16 citation statements)

References 10 publications

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“…These responses are similar to other findings on HR responses using the operative temperature from 20 to 30 C (Hasebe et al, 1995;Nishikawa et al, 1997). In our results on HRV, the responses in HR appeared in CVRESP indicated the significant effect of ambient temperature, reflecting withdrawal of CVRESP in a hot environment.…”

Section: Discussionsupporting

confidence: 92%

“…Heart rate (HR) and its variability have often been used as noninvasive indices to assess cardiac autonomic control which reflects physical or mental load (e.g., Hasebe et al, 1995;Mukae and Sato, 1992;Pagani et al, 1989). The implementation requirements needed to measure the heart rate are particularly lower than other physiological measures (e.g., electroencephalogram, continuous arterial blood pressure and/or blood flow recordings).…”

Section: Introductionmentioning

confidence: 99%

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Analysis of Heart Rate Variability during Mental Task with Reference to Ambient Temperature.

Ishibashi¹,

Yasukouchi²

1999

Appl Human Sci

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Abstract. 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.

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Section: Discussionsupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Analysis of Heart Rate Variability during Mental Task with Reference to Ambient Temperature.

Ishibashi¹,

Yasukouchi²

1999

Appl Human Sci

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“…Environmental conditions were kept constant. Room tem perature was kept at 26°C, and distrac tions due to light and sound were minim alized (11).…”

Section: Experimental Protocolmentioning

confidence: 99%

Venous response to orthostatic stress

Krabbendam¹,

Jacobs²,

Lotgering³

et al. 2008

American Journal of Physiology-Heart and Circulatory Physiology

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Additional material and information about A J P -H eart a n d Circulatory Physiology can be found at:http://www.the-aps.org/publications/ajpheart This infomation is current as of May 11, 2011.A JP -H eart and Circulatory Physiology publishes original investigations on the physiology of the heart, blood vessels, and lymphatics, including experimental and theoretical studies of cardiovascular function at all levels of organization ranging from the intact animal to the cellular, subcellular, and molecular levels. (HUT) induces a re duction in preload, which is thought to be restored through sym pa thetic venoconstriction, reducing unstressed volume (Vu) and venous compliance (VeC). In this study, we assessed venous inflow and outflow responses and their reproducibility and determined the rela tion with autonomic function during HUT. Eight healthy non-pregnant women were subjected to 20° head-down tilt to 60° HUT at 20° intervals. A t each rotational step, we random ly assessed forearm pressure-volume (P-V) curves (venous occlusion plethysmography) during inflow (VeCIN) and outflow [venous emptying rate (VERoUT)]. V eCIN was defined as the ratio o f the slope of the volume-time curve and pressure-time curve, with direct intravenous pressure m easure ment. V EROUT was determined using the derivate of a quadratic regression m odel using cuff pressure. W e defined Vu as the y-intercept of the P-V curve. W e calculated, for both methods, the coefficients of reproducibility (CR) and variation (CV). V ascular sympathetic activ ity was determined by spectral analysis. V eCIN decreased at each rotational step compared with the supine position (P < 0.05), whereas VEROUT increased. CR of VeCIN was higher in the supine position than V EROUT but low er during HUT. CV varied between 19% and 25% (VeCIN) and between 12% and 21% (VEROUT). HUT decreased Vu. The change in V eCIN and V EROUT correlated with the change in vascular sympathetic activity (r = -0.36, P < 0.01, and r = 0.48, P < 0.01). This is the first study in which a reproducible reduction in V eCIN and V u and a rise in V EROUT during HUT are documented. The alterations in venous characteristics relate to changes in vascular sym pathetic activity.head-up tilt; venous compliance; venous emptying rate; venous ca pacity; autonomic system

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“…Both components of the frequency band rose significantly after 10 days of repeated exposures to heat (P L : from 1.97±2. 26 The effect of the P L band on P T , however, was greater than that of the P H band (69% vs. 41%), and the ratio PL/P h was therefore significantly higher (p<0.001) after the tenth day of exposure (Table 3). …”

Section: Time Domain Analysis Demonstrated By Sd and The Interval Rrmentioning

confidence: 83%

Changes in Heart Rate Variability Following Acclimation to Heat

Frank

Belokopytov²,

Moran³

et al. 2001

Journal of Basic and Clinical Physiology and Pharmacology

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We studied the sympatho-vagal balance during acclimation to heat in eight healthy individuals. The subjects, dressed in shorts and tennis shoes, underwent a 10 d procedure of acclimation. Daily exposure lasted 115 min--5 min rest followed by 2 bouts of 50 min exercise (walking on a treadmill at a work load of approximately 350 watt) separated by 10 min rest-at 40 degrees C and 40% relative humidity. We analyzed the time and frequency domains of 256 R-R intervals, toward the end of the second bout of exercise, on the first and tenth days of acclimation. Typical changes for heat acclimation (a reduction in rectal temperature and heart rate, an increase in sweat rate) were observed. Concomitant to a decrease in the final heart rate on the tenth day, sympathetic tone increased. We suggest that, except for the chronotropic response, changes in the sympatho-vagal balance may reflect several adaptive mechanisms of the cardiovascular system. Peripheral factors rather than intrinsic cardiac factors are of relatively greater importance in the direct control of cardiac function.

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Usefulness of R-R interval and its variability in evaluation of thermal comfort

Cited by 19 publications

References 10 publications

Analysis of Heart Rate Variability during Mental Task with Reference to Ambient Temperature.

Analysis of Heart Rate Variability during Mental Task with Reference to Ambient Temperature.

Venous response to orthostatic stress

Changes in Heart Rate Variability Following Acclimation to Heat

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