Changes in haemorheology in the racing greyhound as related to oxygen delivery

Neuhaus, Dorothee; Fedde, M. R.; Gaehtgens, P.

doi:10.1007/bf00705094

Cited by 19 publications

(12 citation statements)

References 33 publications

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“…It is astonishing that birds apparently react to endurance exercise with a decrease in their haematocrit, and not with an increase as mammals generally do (Å strand and Rodahl 1986;Gillen et al 1991;Ernst et al 1991;Neuhaus et al 1992;Collodel et al 1997). Note the general relationship between haematocrit and body mass as well as differences between individuals Fig.…”

Section: Discussionmentioning

confidence: 96%

“…humans and greyhound dogs) and which is partly explained by the withdrawal of fluid to the active muscle cells and the interstitial fluid (e.g. Å strand and Rodahl 1986; Gillen et al 1991;Ernst et al 1991;Neuhaus et al 1992;Collodel et al 1997). However, no change or an increase in the haematocrit has also been observed in humans as a response to exercise (e.g.…”

Section: Introductionmentioning

confidence: 97%

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Effect of endurance flight on haematocrit in migrating birds

et al. 2006

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The effects of an endurance flight on the haematocrit, the percentage of packed red blood cells per blood volume, were examined within the framework of six possible factors explaining possible changes in the haematocrit. Two approaches were adopted: (1) the haematocrit was studied in four species of passerine birds which landed on an Italian island after having crossed the Mediterranean Sea on their spring migration in a non-stop flight; (2) the haematocrit was evaluated in six individual red knots after a flight of 1, 2, 4 and 10 h in a wind tunnel and the data thus obtained compared with data on resting birds with or without food. In the four passerine species, the haematocrit decreased from 51% in fat birds to 48% in lean birds. In lean birds, the haematocrit dropped from 48% in birds with well-developed breast muscles to 36% in birds with emaciated breast muscles. In the red knots, the haematocrit was dependent on body mass in flying and resting birds. The haematocrit decreased from about 51% pre-flight to about 49% within 1 h of flight and remained at this level for up to 10 h of flight. Taking the results from the passerines and the red knots together, it seems that the haematocrit drops by a few percentage points within 1 h after the onset of flight, decreases very slowly with decreasing body mass and decreases more steeply in very lean birds having entered stage III of fasting. This indicates that dehydration is not an underlying factor in decreased haematocrit because if this were the case we would expect an increase with endurance flight. We found no effect of the presence of blood parasites on haematocrit. With the onset of flight, haemodilution may be adaptive, because it reduces blood viscosity and, thereby, energy expenditure by the heart, or it may be a sign of water conservation as an insurance against the risk of dehydration during long non-stop flights. During endurance flight, a reduction in the haematocrit may be adaptive, in that oxygen delivery capacity is adjusted to the decreased oxygen needs as body mass decreases. A decreasing haematocrit would also allow birds to reduce heart beat frequency and/or heart size, because blood viscosity decreases disproportionally with decreasing haematocrit. However, when energy stores are about to come to an end and birds increase protein breakdown, the haematocrit decreases even further, and birds probably become anaemic due to a reduced erythropoiesis.

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Section: Discussionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 97%

Effect of endurance flight on haematocrit in migrating birds

et al. 2006

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“…There is strong evidence that the spleen serves as a blood reservoir in a variety of animals, including racehorses (Boucher & Connes, 2008;Hinchcliff, Kaneps, & Geor, 2008;Persson, Ekman, Lydin, & Tufvesson, 1973;Persson, Funkquist, & Nyman, 1996;Thomas & Fregin, 1981), greyhounds, foxhounds and other types of dog (Guntheroth, McGough, & Mullins, 1967;Guntheroth & Mullins, 1963;Horvath et al, 2014;Longhurst, Musch, & Ordway, 1986;Neuhaus, Fedde, & Gaehtgens, 1992;Rovira, Muñoz, & Benito, 2007;Vatner, Higgins, Millard, Patrick, & Franklin, 1974), sheep (Hodgetts, 1961), guinea pigs (Digges, McPherson, & Summers, 1981) and diving seals (Hochachka et al, 1995;Hurford et al, 1996;Snyder, 1983;Thornton et al, 2001). Horses, for example, show a 65-75% increase of haematocrit during exercise (Boucher & Connes, 2008;Catalini, Dottavio, & Rasia, 2007), and greyhounds present a substantial increase in reticulocyte count (Horvath et al, 2014).…”

Section: Findings In Animal Experimentsmentioning

confidence: 96%

Responses of the human spleen to exercise

Shephard

2015

Journal of Sports Sciences

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The human spleen shows a decrease in volume of around 40% early during vigorous exercise and in response to other stressful stimuli such as maximal apnoea and the breathing of hypoxic gas mixtures. Contraction seems an active response, mediated by alpha-adrenergic fibres in the splenic nerve. Given the relatively small size of the human spleen, the effect upon physical performance is likely to be small; the augmentation of total blood volume is <2%, and even taking account of other causes of haemoconcentration during vigorous exercise, the increase of haematocrit is <10%. However, one of two studies suggested that the haemoconcentration may be sufficient to cause errors in the traditional method for calculating exercise-induced changes of plasma volume. The spleen also contributes leucocytes and platelets to the general circulation as part of the "fight or flight" reaction to stressors. The mobilisation of leucocytes proceeds more slowly than that of the red cells; it depends not only upon an active contraction of the spleen, but also a modulation of leucocyte adhesion molecules. Splenectomy impairs exercise performance in horses, but human performance data are lacking; overall health effects seem minimal, and many patients live many years after removal of their spleens.

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“…Both species are exceptional sprinters 33,34 , have large heart-to-body weight ratios [78][79][80][81] , large contractile spleens (high PCV) 34,37,38,77 , high pulmonary vascular pressures during exercise 12,41 and very high maximal oxygen consumptions 33,35,36,82,83 for their body size. Both species are exceptional sprinters 33,34 , have large heart-to-body weight ratios [78][79][80][81] , large contractile spleens (high PCV) 34,37,38,77 , high pulmonary vascular pressures during exercise 12,41 and very high maximal oxygen consumptions 33,35,36,82,83 for their body size.…”

Section: Discussionmentioning

confidence: 99%

“…Although this condition has been well documented in the Thoroughbred horse since the 17th century 10 and researched extensively, only two preliminary reports provide evidence that greyhounds experience EIPH 8,9 . In horses, the aetiology of EIPH is multifactorial, with high pulmonary artery pressures 11,12 , large airway pressure swings 3,[13][14][15][16][17][18][19][20][21][22] , inflammatory airway disease (IAD) 1,23-29 and ground impact forces [30][31][32] hypothesized to be the major contributing factors. The Thoroughbred horse and racing greyhound are both exceptional sprinters [33][34][35] (c. 18 m s 21 ) with massive cardiac outputs [33][34][35][36] (0.6 and 1.0 l kg 21 min 21 in horse and greyhound, respectively) and exceptional elevations in packed cell volume (PCV; 65 and 66% in horse and greyhound, respectively) 34,35,37,38 during maximal exercise. The Thoroughbred horse and racing greyhound are both exceptional sprinters [33][34][35] (c. 18 m s 21 ) with massive cardiac outputs [33][34][35][36] (0.6 and 1.0 l kg 21 min 21 in horse and greyhound, respectively) and exceptional elevations in packed cell volume (PCV; 65 and 66% in horse and greyhound, respectively) 34,35,37,38 during maxi...…”

Section: Introductionmentioning

confidence: 99%

Evidence supporting exercise-induced pulmonary haemorrhage in racing greyhounds

Epp

Szladovits

Buchannan

et al. 2008

CEP

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Exercise-induced pulmonary haemorrhage (EIPH) is a major health concern in performance horses, but the presence and severity of this condition in racing greyhounds has received little attention. While equids and greyhounds share many physiological attributes, there are important structural and functional differences that may help protect greyhounds from EIPH. We tested the hypothesis that greyhounds performing a simulated 503 m race would experience EIPH and that the time course of recovery would be similar to the horse, even though the severity or relative extent as indexed by the concentration of red blood cells [RBCs] in bronchoalveolar lavage (BAL) fluid would be lower in comparison with that demonstrated previously in horses. Greyhound dogs (n ¼ 6) raced on two occasions (separated by 7 weeks) and BAL was performed 1 week before, 2 h after and each week for 4 weeks following each race to examine the [RBC], concentration of white blood cells [WBCs], WBC differentials and haemosiderophages in the lungs. Racing increased 10 min post-exercise venous blood [lactate] to 18.6^0.4 mmol l 21 . No epistaxis or pink froth was observed at the nose or mouth of any of the dogs. The [RBC] in the BAL fluid was increased significantly 2 h post-race (baseline ¼ 109.6^11.7 £ 10 3 ; post-race ¼ 292.3^69.9 £ 10 3 RBC ml 21 BAL fluid, P , 0.05) and returned to baseline 1 week post-race (149.2^46.2 £ 10 3 RBC ml 21 BAL fluid, P . 0.05 versus baseline). The number of haemosiderophages was not different for any of the measurement periods. The [WBC] in the BAL fluid decreased from baseline and race values at 2, 3 and 4 weeks post-exercise (all P , 0.05). Alveolar neutrophil concentrations were also decreased from baseline and immediate post-race values for 4 weeks post-race. The increased [RBC] in the BAL fluid post-exercise is consistent with the presence of EIPH in these greyhounds. However, the relative extent of EIPH in greyhounds (as indexed by [RBC] in the BAL fluid), as compared with that in the horse, was mild, and the lack of elevation of WBC suggests that, unlike their equine counterparts, inflammatory airway disease was absent.

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Changes in haemorheology in the racing greyhound as related to oxygen delivery

Cited by 19 publications

References 33 publications

Effect of endurance flight on haematocrit in migrating birds

Effect of endurance flight on haematocrit in migrating birds

Responses of the human spleen to exercise

Evidence supporting exercise-induced pulmonary haemorrhage in racing greyhounds

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