Responses to exercise in the pregnant pygmy goat

Dhindsa, Dharam S.; Metcalfe, James; Hummels, Dean H.

doi:10.1016/0034-5687(78)90118-4

Cited by 24 publications

(21 citation statements)

References 8 publications

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“…We use the thermodilution technique of measuring cardiac output. Our non-pregnant resting measurements compared favourably with cardiac output measurements in nonpregnant pygmy goats using the indicator dye dilution method previously reported from our laboratory (3 25+0 50 1/min vs. 3-45+0 59 1/min, thermodilution vs. dye dilution respectively), however, the resting thermodilution outputs were higher in our pregnant animals compared to those previously reported (Dhindsa et al 1978). This is likely explained by the small numbers of animals in the prior study and the different gestational ages used.…”

Section: Discussioncontrasting

confidence: 53%

“…The goats walked on the treadmill at 0 grade and 2 4 km/h (1 5 miles/h) until balking was noted at which time haemodynamic measurements were made and exercise terminated. In our experience and from other measurements in our laboratory (Dhindsa et al 1978;Hohimer et al 1984) we do not believe that this was maximal exercise for the animals, but was the most that they would perform without noxious stimulation. Our goal was to assess the affects of exercise and pregnancy on the circulation and keep psychological perturbations to a minimum.…”

Section: Study Protocolmentioning

confidence: 95%

“…In humans, heart rate and stroke volume increase with exercise, but the amount of stroke volume increase appears dependent upon posture and gestational age (Bader, Bader, Rose & Braunwald, 1955;Ueland, Novy, Peterson & Metcalfe, 1969;Guzman & Caplan, 1970. ) In pygmy goats, heart rate and stroke volume increase (stroke volume by 3300) at peak exercise (Dhindsa, Metcalfe & Hummels, 1978), and in sheep, the exercise increase in cardiac output is primarily heart rate mediated with only a small contribution from stroke volume (Curet, Orr, Rankin & Ungerer, 1976;Lotgering, Gilbert & Longo, 1983). Problems with these previous studies include small numbers of animals (Dhindsa et al 1978), exercise to exhaustion with volume depletion (Curet et al 1976;Lotgering et al 1983) and determination of cardiac output immediately following rather than during exercise (Curet et al 1976).…”

Section: Introductionmentioning

confidence: 99%

“…) In pygmy goats, heart rate and stroke volume increase (stroke volume by 3300) at peak exercise (Dhindsa, Metcalfe & Hummels, 1978), and in sheep, the exercise increase in cardiac output is primarily heart rate mediated with only a small contribution from stroke volume (Curet, Orr, Rankin & Ungerer, 1976;Lotgering, Gilbert & Longo, 1983). Problems with these previous studies include small numbers of animals (Dhindsa et al 1978), exercise to exhaustion with volume depletion (Curet et al 1976;Lotgering et al 1983) and determination of cardiac output immediately following rather than during exercise (Curet et al 1976). Haemodynamic observations during recovery have been reported only in humans following upright bicycle exercise (Morton, Paul, Campos, Hart & Metcalfe, 1985).…”

Section: Introductionmentioning

confidence: 99%

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Maternal Heart Rate and Stroke Volume in the Pygmy Goat: Effects of Exercise and Cardiac Autonomic Blockade

et al. 1986

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SUMMARYTo determine the normal maternal heart rate and stroke volume response to exercise and the role of the autonomic nervous system in this response, pregnant and non-pregnant pygmy goats were studied at rest, during and following treadmill exercise, and after autonomic blockade. Resting heart rates, stroke volumes and cardiac outputs were 10%, 60%, and 76% higher in pregnant compared to non-pregnant animals (P < 0 05, 0 001, and 0 001 respectively). During exercise, heart rate and stroke volume rose in both pregnant and non-pregnant animals by similar amounts. Immediately post-exercise, stroke volume in pregnant animals dropped precipitously below resting levels by 15% (P < 0005) but cardiac output was preserved by heart rate. This fall in stroke volume was not seen in control animals. Autonomic blockade lowered resting and exercise heart rates in both groups without changing stroke volume. The elevations in heart rate and stroke volume in pregnancy are not primarily mediated via the autonomic nervous system. Although the maternal cardiac output response to exercise appears normal, the post-exercise fall in stroke volume, presumed secondary to a reduction in preload, could potentially be harmful to both mother and fetus.

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Section: Discussioncontrasting

confidence: 53%

Section: Study Protocolmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Maternal Heart Rate and Stroke Volume in the Pygmy Goat: Effects of Exercise and Cardiac Autonomic Blockade

et al. 1986

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“…(5) T o w hat d eg re e does exercise affect m atern al a n d fetal resp ira to ry blood gases? (6) Is th e re evidence fo r acute fetal distress d u rin g exercise? (7) Is fetal outcom e affected by rep e ate d stren u o u s physical activity d u rin g pregnancy?…”

mentioning

confidence: 99%