Further studies on the metabolic effects of long distance riding: Golden Horseshoe Ride 1979

Abstract

Summary Blood samples were taken before and immediately after 80 km and 40 km rides held on consecutive days and analysed for haematocrit, blood glucose and lactate, plasma sodium, potassium, calcium, albumin, free fatty acids (FFA), glycerol, bicarbonate, insulin, cortisol, glucagon, urea, creatinine, uric acid, bilirubin and alkaline phosphatase. Unusually hot weather probably contributed to haemoconcentration with a significant (P<0.001) increase in haematocrit and plasma albumin. A fall in blood glucose, with a rise in FFA and glycerol were consistent with long distance riding and were associated with a reduction in plasma insulin and a rise in cortisol and glucagon. The results suggested that the horses were working aerobically and the small increase in blood lactate was likely to be a result of reduced tissue perfusion. Plasma urea, creatinine and bilirubin increased during the 80 km ride and were still high the next morning. Blood samples were taken from 2 horses that became exhausted and were forced to retire and the results from these animals indicate the slow rate of recovery. It is suggested that haemoconcentration with reduced tissue perfusion might contribute to exhaustion during long distance exercise and that the speed of recovery might be improved by the intravenous administration of balanced electrolyte solutions. Résumé Avant et immédiatement après des raids de 40 et de 80 km effectués en deux jours consëcutifs, on a prélevé des échantillons de sang. Ces échantillons ont été analysés pour y rechercher l'hématocrite, la glycémie, la lactacidèmie, le sodium, le potassium et le calcium plasmatiques, l'albumine, les acides gras non saturés, la bilirubine et les phosphatases alcalines. Un temps particulièrement chaud favorisa probablement une hémoconcentration entraînant une élévation significative (P <0.001) de l'hématocrite et de l'albumine du plasma. On constata une chute du glucose sanguin, une élévation des acides gras non saturés et du glycerol associés à la diminution de l'insuline et à l'augmentation du cortisol et du glucagon. Ces résultats indiqueraient que les chevaux ont travaillé en aérobie; une légère élévation des lactates sanguins paraîtrait indiquer une perfusion tissulaire réduite. L'urée plasmatique, la créatinine et la bilirubine augmentèrent durant l'épreuve de 80 kilomètres et leurs niveaux étaient encore élevés le lendemain matin. Des prélèvements sanguins obtenus sur deux chevaux, épuisés au point d'abandonner, ont permis de constater la lenteur de la récupération. On suppose que l'hémoconcentration, parce qu'elle réduit la perfusion des tissus, peut contribuer à l'épuisement lors des raids. On pense que la vitesse de récupération peut étre améliorée par l'administration intra‐veineuse de solutions équilibrées d'électrolytes. Zusammenfassung Vor und unmittelbar nach Distanzritten über 80 und 40 km an aufeinanderfolgenden Tagen wurde Blut entnommen und untersucht auf Haematokrit, Blutglucose, Laktat, Plasmanatrium, ‐kalium, ‐calcium, ‐albumin, freie Fettsäuren, Glycerin, Bicarb...

Physiological Parameters of Endurance Horses Pre- Compared to Post-Race, Correlated with Performance: A Two Race Study from Scandinavia

“…A small significant increase in haemoglobin was found in the first post-race sample with a significant decrease to the second post-race sample. Both of these findings are described in previous studies [12, 14, 15, 26–29]. …”

Fibre types, enzyme activities and substrate utilisation in skeletal muscles of horses competing in endurance rides

“…This is a relatively new sport in Sweden, however, and in 1980 endurance rides over either 100 or 50 km were held for only the second time. Physiological studies of such events have been mainly limited to biochemical measurements of blood (Carlson and Mansmann 1974;Rose, Purdue and Hensley 1977; Rose et a1 1980; Lucke and Hall 1980) and in only two studies have muscle fibre characteristics and glycogen depletion been reported from muscle biopsies (Snow, Baxter and Rose 1981;Snow, Kerr, Nimmo and Abbott 1982).…”

“…It has been implied that the decrease in blood glucose during prolonged exercise suggests an increased uptake of glucose by muscle and the rise in plasma non-esterified fatty acids indicates an increased rate of lipolysis (Lindholm 1979;Lucke and Hall 1980). Furthermore, it has been shown that intramuscular glycogen and triglycerides are both used as fuels during prolonged trotting (Lindholm 1979).…”

Exertional heat illness: a review of the syndrome affecting racing Thoroughbreds in hot and humid climates

“…[11][12][13] In these horses, exercise is largely aerobic and performed over longer distances, with dehydration becoming the driving factor in the pathophysiology of heat exhaustion. [11][12][13] An exercise-induced heat stress syndrome affecting Thoroughbred racehorses in Australia has been described and labelled 'exertional heat illness' (EHI). 14 The clinical signs and features of EHI were similar to those described in a retrospective study based on race records of 375,701 horses collected over a 21-year period in South Africa that reported a syndrome referred to as 'postrace distress syndrome' in racing Thoroughbreds.…”