The effects of exercise and changes in body temperature on the intrinsic heart rate in man

Jose, Anthony D.; Stitt, Frank W.; Collison, Damien

doi:10.1016/0002-8703(70)90254-1

Cited by 135 publications

(86 citation statements)

References 20 publications

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“…In the present study, in keeping with results from previous studies (Jose et al, 1970), heart rate increased with exercise following autonomic blockade. This increase cannot be explained by incomplete autonomic blockade as Valsalva manoeuvres performed after each exercise session confirmed the effectiveness of the parasympathetic and sympathetic blockade.…”

Section: Discussionsupporting

confidence: 93%

“…Intrinsic heart rate (IHR), heart rate following autonomic (P-adrenoceptor and muscarinic) blockade, increases with exercise (Jose et al, 1970). The cause of this increase is unknown.…”

Section: Introductionmentioning

confidence: 99%

“…The cause of this increase is unknown. Possible mechanisms include exercise-induced rises in central body temperature (Pickering, 1958) and/or neural-humoral influences other than those mediated by the autonomic nervous system (Jose et al, 1970). These neural-humoral influences include exercise-induced rises in angiotensin II, aldosterone, cortisol and ,-endorphin, all of which are further enhanced in the presence of naloxone (Staessen et al, 1988).…”

Section: Introductionmentioning

confidence: 99%

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Increases in plasma beta‐endorphin concentrations during exercise do not contribute to increases in heart rate following autonomic blockade in man.

Strömberg¹,

Chin²,

Fullerton³

et al. 1992

Brit J Clinical Pharma

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Section: Discussionsupporting

confidence: 93%

“…Intrinsic heart rate (IHR), heart rate following autonomic (P-adrenoceptor and muscarinic) blockade, increases with exercise (Jose et al, 1970). The cause of this increase is unknown.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Increases in plasma beta‐endorphin concentrations during exercise do not contribute to increases in heart rate following autonomic blockade in man.

Strömberg¹,

Chin²,

Fullerton³

et al. 1992

Brit J Clinical Pharma

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“…Accordingly, it has been suggested that the increase in heart rate during sustained constant-load exercise in the heat is only partly related to the reduction in V O 2peak , with the remainder of the increase associated with other factors (2). The greater increase in heart rate is proposed to occur as a result of an elevation in sympathetic nervous activity and vagal withdrawal, as well as via the direct effect of blood temperature on the sinoatrial node (i.e., pacemaker tissue located in the right atrium) (16,21,22). The latter has been shown to produce an increase in heart rate of 7-8 beats·min Ϫ1 ·°C Ϫ1 (14,16,21).…”

Section: Discussionmentioning

confidence: 99%

“…The greater increase in heart rate is proposed to occur as a result of an elevation in sympathetic nervous activity and vagal withdrawal, as well as via the direct effect of blood temperature on the sinoatrial node (i.e., pacemaker tissue located in the right atrium) (16,21,22). The latter has been shown to produce an increase in heart rate of 7-8 beats·min Ϫ1 ·°C Ϫ1 (14,16,21). Hence, with progressive increases in ambient and concomitantly core temperature, the increase in heart rate during exercise-heat stress may be more pronounced for a given increase in %V O 2peak than in cooler conditions (2).…”

Section: Discussionmentioning

confidence: 99%

Self-paced exercise in hot and cool conditions is associated with the maintenance of %V̇o_2peak within a narrow range

Périard

Racinais

2015

Journal of Applied Physiology

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Périard JD, Racinais S. Self-paced exercise in hot and cool conditions is associated with the maintenance of %V O2peak within a narrow range. J Appl Physiol 118: 1258 -1265. First published March 26, 2015 doi:10.1152/japplphysiol.00084.2015.-This study examined the time course and extent of decrease in peak oxygen uptake (V O2peak) during self-paced exercise in HOT (35°C and 60% relative humidity) and COOL (18°C and 40% relative humidity) laboratory conditions. Ten well-trained cyclists completed four consecutive 16.5-min time trials (15-min self-paced effort with 1.5-min maximal end-spurt to determine V O2peak) interspersed by 5 min of recovery on a cycle ergometer in each condition. Rectal temperature increased significantly more in HOT (39.4 Ϯ 0.7°C) than COOL (38.6 Ϯ 0.3°C; P Ͻ 0.001). Power output was lower throughout HOT compared with COOL (P Ͻ 0.001). The decrease in power output from trial 1 to 4 was ϳ16% greater in HOT (P Ͻ 0.001). Oxygen uptake (V O2) was lower throughout HOT than COOL (P Ͻ 0.05), except at 5 min and during the end-spurt in trial 1. In HOT, V O2peak reached 97, 89, 85, and 85% of predetermined maximal V O2, whereas in COOL 97, 94, 93, and 92% were attained. Relative exercise intensity (%V O2peak) during trials 1 and 2 was lower in HOT (ϳ84%) than COOL (ϳ86%; P Ͻ 0.05), decreasing slightly during trials 3 and 4 (ϳ80 and ϳ85%, respectively; P Ͻ 0.05). However, heart rate was higher throughout HOT (P ϭ 0.002), and ratings of perceived exertion greater during trials 3 and 4 in HOT (P Ͻ 0.05). Consequently, the regulation of self-paced exercise appears to occur in conjunction with the maintenance of %V O2peak within a narrow range (80-85% V O2peak). This range widens under heat stress, however, when exercise becomes protracted and a disassociation develops between relative exercise intensity, heart rate, and ratings of perceived exertion. cardiovascular strain; cycling; fatigue; hyperthermia; pacing; thermoregulation; time trial; V O2max SELF-PACED (I.E., TIME TRIAL) exercise requires the completion of a known distance in the quickest possible time or the production of the greatest amount of work in a set duration (1, 11). When undertaken in the heat, prolonged self-paced exercise performance is significantly impaired relative to cool conditions (10,27,28,42,46). The impairment in performance is mediated by the complex interplay of multiple physiological systems (e.g., nervous, metabolic) (8,34,45), with the development of thermal strain potentially modulating a performance-limiting increase in cardiovascular strain (5,27,28,30). Indeed, a narrowing core-to-skin temperature gradient during exercise-heat stress increases the skin blood flow requirement for heat dissipation (5,35,36). The combination of an increase in cutaneous blood volume and a temperature-mediated rise in intrinsic heart rate decreases cardiac filling, which leads to reductions in stroke volume and maximal cardiac output when heart rate approaches maximum (6,13,15,36). During prolonged constant-load exercise to exhaustion...

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Diurnal changes and reproducibility of corrected sinus node recovery time

Thormann

Schlepper

Krämer

1983

Cathet. Cardiovasc. Diagn.

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Corrected sinus node recovery time (CSRT) has been found unreliable in identifying all cases of sick sinus syndrome. Since other factors than sinus node dysfunction might add to the pathologic significance of the CSRT, we assessed it in 15 patients (nine group I patients with "prolonged" CSRT max = 3,196 + 2,740 msec and six group II patients with "short" CSRT max = 367 + 79 msec) at 0800, 1100, 1400, 1700, 2000, and 2300 hours with atrial overdrive stimulation rates (AST) of 90, 110, 140, 170, and 200 bpm on three consecutive days using a loop-mounted stable atrial electrode. Only with AST greater than or equal to 140 beats per minute (bpm) did all CSRTI values prove prolonged (greater than or equal to 560 msec). CSRTI values at corresponding time intervals were reproducible with AST greater than or equal to 140 bpm (day 1 vs 2 vs 3, P greater than .05), but not at AST 90 bpm and 110 bpm (P less than .05); CSRTII results, however, varied from day to day (less than .05) due to less scatter of single results. CSRTI results increased progressively with AST 90, 110, and 140 bpm from 301 + 256 msec by 60% for each pacing rate up to 785 + 848 msec. With AST greater than or equal to 140 bpm, the pattern of CSRT changes was inconsistent; this was also reflected by the distribution of the mean maxima of CSRTI: For 0800 hours at AST 140 bpm = 822 + 937 msec; for 1100 hours at AST 200 bpm = 824 + 1446 msec; for 1400 hours at AST 140 bpm = 780 + 814 msec; for 1700 hours at AST 170 bpm = 1,099 + 1,008 msec; for 2000 hours at AST 200 bpm = 1,156 + 1,280 msec; and for 2300 hours at AST 170 bpm = 1,021 + 1,102 msec. We conclude therefore that the optimal diagnostic yield for sick sinus syndrome testing is influenced by the time of the day and the AST used for CSRT testing.

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The effects of exercise and changes in body temperature on the intrinsic heart rate in man

Cited by 135 publications

References 20 publications

Increases in plasma beta‐endorphin concentrations during exercise do not contribute to increases in heart rate following autonomic blockade in man.

Increases in plasma beta‐endorphin concentrations during exercise do not contribute to increases in heart rate following autonomic blockade in man.

Self-paced exercise in hot and cool conditions is associated with the maintenance of %V̇o_2peak within a narrow range

Diurnal changes and reproducibility of corrected sinus node recovery time

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The effects of exercise and changes in body temperature on the intrinsic heart rate in man

Cited by 135 publications

References 20 publications

Increases in plasma beta‐endorphin concentrations during exercise do not contribute to increases in heart rate following autonomic blockade in man.

Increases in plasma beta‐endorphin concentrations during exercise do not contribute to increases in heart rate following autonomic blockade in man.

Self-paced exercise in hot and cool conditions is associated with the maintenance of %V̇o2peak within a narrow range

Diurnal changes and reproducibility of corrected sinus node recovery time

Contact Info

Product

Resources

About

Self-paced exercise in hot and cool conditions is associated with the maintenance of %V̇o_2peak within a narrow range