Right atrial pressure and forearm blood flow during prolonged exercise in a hot environment

Nosé, Hiroshi; Takamata, Akira; Mack, Gary W.; Oda, Yoshinobu; Kawabata, Takashi; Hashimoto, Satoru; Hirose, Munetaka; Chihara, Eiichi; Morimoto, Taketoshi

doi:10.1007/bf00374769

Cited by 29 publications

(20 citation statements)

References 23 publications

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“…2, C-E). This agrees with the observations that most of the reductions in central blood volume and right atrial pressure with heat stress occur early in exercise (31,35) and that right atrial pressure declines only slightly after skin blood flow has reached a plateau level (31). As shown in Fig.…”

Section: Cardiovascular Responses To Exercisesupporting

confidence: 91%

Influence of body temperature on the development of fatigue during prolonged exercise in the heat

González‐Alonso

Teller

Andersen

et al. 1999

Journal of Applied Physiology

891

741

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Nielsen. Influence of body temperature on the development of fatigue during prolonged exercise in the heat. J. Appl. Physiol. 86(3): 1032-1039, 1999.-We investigated whether fatigue during prolonged exercise in uncompensable hot environments occurred at the same critical level of hyperthermia when the initial value and the rate of increase in body temperature are altered. To examine the effect of initial body temperature [esophageal temperature (T es ) ϭ 35.9 Ϯ 0.2, 37.4 Ϯ 0.1, or 38.2 Ϯ 0.1 (SE)°C induced by 30 min of water immersion], seven cyclists (maximal O 2 uptake ϭ 5.1 Ϯ 0.1 l/min) performed three randomly assigned bouts of cycle ergometer exercise (60% maximal O 2 uptake) in the heat (40°C) until volitional exhaustion. To determine the influence of rate of heat storage (0.10 vs. 0.05°C/min induced by a water-perfused jacket), four cyclists performed two additional exercise bouts, starting with T es of 37.0°C. Despite different initial temperatures, all subjects fatigued at an identical level of hyperthermia (T es ϭ 40.1-40.2°C, muscle temperature ϭ 40.7-40.9°C, skin temperature ϭ 37.0-37.2°C) and cardiovascular strain (heart rate ϭ 196-198 beats/min, cardiac output ϭ 19.9-20.8 l/min). Time to exhaustion was inversely related to the initial body temperature: 63 Ϯ 3, 46 Ϯ 3, and 28 Ϯ 2 min with initial T es of ϳ36, 37, and 38°C, respectively (all P Ͻ 0.05). Similarly, with different rates of heat storage, all subjects reached exhaustion at similar T es and muscle temperature (40.1-40.3 and 40.7-40.9°C, respectively), but with significantly different skin temperature (38.4 Ϯ 0.4 vs. 35.6 Ϯ 0.2°C during high vs. low rate of heat storage, respectively, P Ͻ 0.05). Time to exhaustion was significantly shorter at the high than at the lower rate of heat storage (31 Ϯ 4 vs. 56 Ϯ 11 min, respectively, P Ͻ 0.05). Increases in heart rate and reductions in stroke volume paralleled the rise in core temperature (36-40°C), with skin blood flow plateauing at T es of ϳ38°C. These results demonstrate that high internal body temperature per se causes fatigue in trained subjects during prolonged exercise in uncompensable hot environments. Furthermore, time to exhaustion in hot environments is inversely related to the initial temperature and directly related to the rate of heat storage. hyperthermia; skin blood flow; heart rate; stroke volume IT IS WELL DOCUMENTED that endurance can be impaired in hot compared with temperate climates (10,12,28) and that time to exhaustion is influenced by alterations of the initial body temperature (1,22,32,39). The attainment of a critically high level of body temperature has been proposed as the main factor limiting endurance performance in hot environments (7,28). The observation that trained subjects working at 60% of peak O 2 uptake (V O 2 peak ) in the heat [40°C, 10% relative humidity (RH)] for 9-12 consecutive days improved exercise performance from 48 to 80 min but fatigued at a core temperature of 39.7°C appears to support this notion (28). This large improvement in exercise time t...

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Section: Cardiovascular Responses To Exercisesupporting

confidence: 91%

Influence of body temperature on the development of fatigue during prolonged exercise in the heat

González‐Alonso

Teller

Andersen

et al. 1999

Journal of Applied Physiology

891

741

View full text Add to dashboard Cite

show abstract

“…However, this early stable phase may occur due to an increase in sympathetic nerve tone. During prolonged exercise, vasodilatation in cutaneous blood vessels and in active muscle may occur with an increase in body temperature and metabolites, and consequently arterial blood pressure can be reduced (2,7,13). In this case, sympathetic nerve tone is increased to maintain blood pressure (14).…”

Section: Discussionmentioning

confidence: 99%

“…The rise in cutaneous blood flow is thought to lead to an increase in cutaneous venous volume, thus reducing ventricular filling pressure, end-diastolic volume and SV during submaximal exercise (16). Indeed, right atrial pressure progressively decreases during prolonged exercise (13).…”

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confidence: 99%

“…Their data showed that blood volume in skin plus active muscle increased after the start of exercise and that the rate of increase became lower, whereas HR increased at a constant rate for 60 min. It has also been shown that cutaneous blood flow, directly or indirectly determined, remains fairly stable after 20-30 min of exercise (5,8,13). Therefore, it is likely that HR drift is associated with factors other than changes in cutaneous blood volume and in blood volume in skin plus active muscle, at least after 20-30 min.…”

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Effect of change in blood volume in skin plus active muscle on heart rate drift during submaximal exercise

Yano

Yunoki²,

Matsuura³

et al. 2008

Acta Physiologica Hungarica

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The purpose of the present study was to examine the effect of change in blood volume in skin plus active muscle on heart rate drift during moderate exercise and heavy exercise for 30 min. Total hemoglobin concentration (Total Hb) in the vastus lateralis muscle plus its skin was determined by near-infrared spectroscopy. Total Hb significantly increased and remained stable from 20 min in moderate exercise and from 10 min in heavy exercise. Heart rate (HR) rapidly increased until 3 min and showed a steady state in moderate exercise. HR at 30 min was significantly higher than that at 3 min in moderate exercise. HR rapidly increased until 3 min and then gradually but significantly increased in heavy exercise. Increase in total Hb was not significantly related with HR after 3 min of exercise when HR was around 120 beats per min in moderate exercise. Increase in total Hb was significantly related with HR from 3 min to 10 min in the heavy exercise (correlation coefficients ranged from 0.959 to 0.702). It is concluded that an increase in the blood volume in skin plus active muscle is not simply associated with HR drift

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“…However, it has been observed that stroke volume continuously decreased despite a plateau in skin blood volume during the latter half of prolonged exercise for 60 min (Ricardo et al, 1999). Nose et al (1990Nose et al ( , 1994 reported that HR upward drift occurred in spite of attaining a CBF plateau. These studies suggest that the decline in stroke volume might not be related to an increase in CBF.…”

Section: Introductionmentioning

confidence: 99%

Effect of Blood Volume in Resting Muscle on Heart Rate Upward Drift during Moderately Prolonged Exercise

Kimura

Matsuura

Arimitsu

et al. 2010

J Physiol Anthropol

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The aim of this study was to determine whether the increase in blood volume in resting muscle during moderately prolonged exercise is related to heart rate (HR) upward drift. Eight healthy men completed both arm-cranking moderately prolonged exercise (APE) and leg-pedaling moderately prolonged exercise (LPE) for 30 min. Exercise intensity was 120 bpm of HR that was determined by ramp incremental exercise. During both APE and LPE, HR significantly increased from 3 to 30 min (from 108Ϯ9.3 to 119Ϯ12 bpm and from 112Ϯ8.9 to 122Ϯ11 bpm, respectively). However, there was no significant difference between HR in APE and that in LPE. Oxygen uptake was maintained throughout the two exercises. Skin blood flow, deep temperature, and total Hb (blood volume) in resting muscle continuously increased for 30 min of exercise during both APE and LPE. During both APE and LPE, there was a significant positive correlation between total Hb and deep temperature in all subjects. Moreover, there was a significant positive correlation between HR and total Hb (in seven out of eight subjects) during LPE. However, during APE, there was no positive correlation between HR and total Hb (rϭ0.391). These findings suggest that an increase of blood pooling in resting muscle could be proposed as one of the mechanisms underlying HR upward drift during moderately prolonged exercise.

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Right atrial pressure and forearm blood flow during prolonged exercise in a hot environment

Cited by 29 publications

References 23 publications

Influence of body temperature on the development of fatigue during prolonged exercise in the heat

Influence of body temperature on the development of fatigue during prolonged exercise in the heat

Effect of change in blood volume in skin plus active muscle on heart rate drift during submaximal exercise

Effect of Blood Volume in Resting Muscle on Heart Rate Upward Drift during Moderately Prolonged Exercise

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