Effects of temperature, immersion, and ambient pressure on human apneic bradycardia.

Moore, Tom; Lin, Yandan; Lally, D A; Hong, Suk Ki

doi:10.1152/jappl.1972.33.1.36

Cited by 45 publications

(15 citation statements)

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“…was stronger with lower water temperatures (Figs. 2 and 3), as reported previously for diving bradycardia (Kawakami et al 1967;Song et al 1969;Moore et al 1972). However, a clear increase was seen also in lukewarm water (Fig.…”

Section: Discussionsupporting

confidence: 72%

The diving response in man: effects on sympathetic activity in muscle and skin nerve fascicles.

Fagius¹,

Sundlöf²

1986

The Journal of Physiology

114

102

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SUMMARY1. Multi-unit recordings of muscle-nerve sympathetic activity (m.s.a) or skin-nerve sympathetic activity (s.s.a) were made in the left peroneal nerve of sixteen healthy volunteers during simulated diving by immersion of the face in a tub of water. The procedure was varied by the use of different water temperatures, by diving with snorkel breathing, by apnoea without diving, and by apnoea with a stream of air against the face instead of immersion in water.2. Diving for 12 s elicited a pronounced activation of m.s.a., the mean increase from control periods being 360 %. The response was stronger with lower water temperatures.Immersion of the whole face evoked a stronger increase in m.s.a. than immersion of mouth and nose only. Diving without apnoea elicited a significant but weaker increase in m.s.a., whereas apnoea only for 12 s did not influence the sympathetic outflow.Cool air against the face during apnoea for 12 s was associated with a significant increase in m.s.a. 3. The increase in m.s.a. usually occurred before the bradycardia. On emersion, m.s.a. ceased abruptly, whereas the bradyeardia persisted for a few seconds. Mental arithmetic during diving did not change the m.s.a. response but reduced the bradyeardia. M.s.a. increased despite increasing blood pressure levels. On emersion, m.s.a. did not reappear until the pre-diving blood pressure level was attained.4. S.s.a was inhibited on diving, with concomitant vasodilatation in the skin as recorded in the big toe.5. It is concluded that the response of m.s.a. to diving is initiated by a central 'pattern recognition' of an input from facial receptors, that this input and the effects of apnoea, acting by mutual reinforcement, maintain the strong sympathetic outflow, and that the mechanism releasing m.s.a. on diving overrides the normal blood pressure regulatory function of m.s.a. Diving exerts differentiated influence on different parts of the sympathetic nervous system, as illustrated by the inhibition of s.s.a.

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Section: Discussionsupporting

confidence: 72%

The diving response in man: effects on sympathetic activity in muscle and skin nerve fascicles.

Fagius¹,

Sundlöf²

1986

The Journal of Physiology

114

102

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“…The decrease in HR during breathholding is similar to that observed in air when the subject is fully immersed at neutral water temperature, but much larger when water temperature is lower than neutral (Moore et al 1972;Sterba and Lundgren 1985;Lemaitre et al 2005;Hansel et al 2009). BP data during breath-hold diving are scarce.…”

Section: Introductionsupporting

confidence: 64%

Cardiovascular time courses during prolonged immersed static apnoea

et al. 2010

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To define the dynamics of cardiovascular adjustments to apnoea during immersion, beat-to-beat heart rate (HR) and systolic (SBP) and diastolic (DBP) blood pressures were recorded in six divers during and after prolonged apnoeas while resting fully immersed in 27 degrees C water. Apnoeas lasted 215 +/- 35 s. Compared to control values, HR decreased by 20 beats min(-1) and SBP and DBP increased by 23 and 17 mmHg, respectively, in the initial 20 +/- 3 s (phase I). Both HR and BP remained stable during the following 92 +/- 15 s (phase II). Subsequently, during the final 103 +/- 29 s, SBP and DBP increased linearly to values about 60% higher than control, whereas HR remained unchanged (phase III). Cardiac output (Q') decreased by 35% in phase I and did not further change in phases II and III. Compared to control, total peripheral resistances were twice and three times higher than control, respectively, at the end of phases I and III. After resumption of breathing, HR and BP returned to control values in 5 and 30 s, respectively. The time courses of cardiovascular adjustments to immersed breath-holding indicated that cardiac response took place only at the beginning of apnoea. In contrast, vascular responses showed two distinct adjustments. This pattern suggests that the chronotropic control via the baroreflex is modified during apnoea. These cardiovascular changes during immersed static apnoea are in agreement with those already reported for static dry apnoeas.

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“…Daly, 1984) that it is the combination of face immersion with apnoea which provokes the maximal cardiovascular response. Many FACE IMMERSION AND VENTILATORY DRIVE studies, in man and in animals, have shown that the important factors in determining the size of the 'diving response' are the wetting of the face (Wolf, Schneider & Groover, 1965; Moore, Lin, Lally & Hong, 1972), the immersion of the skin supplied by the trigeminal nerve (Gooden, Lehman & Pym, 1970;Stromme, Kerem & Elsner, 1970), and the coldness of the water (Whayne & Killip, 1967; Kawakami, Natelson & DuBois, 1967). Immersion of the nasal mucosa, prevented by the nose-clip in the present study, enhances the response but is not essential for it (Campbell, Gooden & Horowitz, 1969).…”

Section: Effect Of Cold Face-packs On Exercise Ventilationmentioning

confidence: 99%

Ventilatory drive during face immersion in man.

Mukhtar¹,

Patrick²

1986

The Journal of Physiology

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SUMMARY1. Four series ofexperiments have been performed in normal subjects to determine whether face immersion gives rise to a reduction in ventilatory drive. Such a response might be advantageous, like the cardiovascular components of the 'diving response', in prolonging breath-hold diving.2. In the first series, ventilatory drive was measured indirectly as the maximal voluntary breath-holding time, starting each breath-hold at the same alveolar partial pressures and at the same lung volume. When the face was immersed in cold water, breath-holding times were increased by 14 %. The breaking point occurred at a higher alveolar PCO2 and the rate of rise of PCO2 was not affected. Control immersions in warm water had no effect.3. In the second and third series, subjects lay prone and breathed either air or 5 % CO2 through a valve in the bottom of a bowl. Minute ventilation was measured before, during and after 5 min of face immersion in cold water. Transient hypoventilations of 13 % and 10 % respectively were seen, accompanied by small rises in alveolar PCo2.In control experiments, immersion ofthe forearm in cold water produced the opposite responses.4. In the fourth series, a cold wet pack was applied to the face during moderate steady-state exercise. A small irregular hypoventilation was seen, but not in control experiments when a warm pack was applied.5. Face temperatures fell by about 10 TC in these experiments. No material changes were found in the temperatures of the inspired air or of the aural canal. 6. It is concluded that face immersion in cold water causes a modest reduction in ventilatory drive in man. This appears to be a component of the 'diving response'.

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Effects of temperature, immersion, and ambient pressure on human apneic bradycardia.

Cited by 45 publications

References 0 publications

The diving response in man: effects on sympathetic activity in muscle and skin nerve fascicles.

The diving response in man: effects on sympathetic activity in muscle and skin nerve fascicles.

Cardiovascular time courses during prolonged immersed static apnoea

Ventilatory drive during face immersion in man.

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