Effects of training on cardiorespiratory function in the horse

Abstract

The effects of 5- and 10-wk treadmill exercise training on cardiorespiratory function were evaluated in the horse. Cardiac output (Q), heart rate (HR), and stroke volume (SV), as well as left ventricular (LVP), aortic (AoP), and mean right atrial (RAP) pressures and the peak first time derivative of LVP (LV dP/dtmax), were measured at rest and at five different levels of exercise up to 90% of initial predicted maximal HR (HRmax). Oxygen uptake (VO2) and respiratory exchange ratio (R) were also obtained under the same conditions. At rest, although HR was no different after training, LV dP/dtmax was lower at 10 wk (2,369 +/- 502 vs. 1,615 +/- 302 mmHg/s). At the different measured work loads during exercise, Q and VO2 remained unchanged with training, whereas there were consistent trends toward lower LVP, AoP, and LV dP/dtmax and significant reductions in HR and R (both P less than 0.05). In contrast, SV and mean RAP were elevated (P less than 0.05) during exercise after the 10-wk training program. Although the observed changes in cardiorespiratory function in response to a training program in the horse are generally similar to those reported for other species, our data also suggest a training-induced increase in venous pressures during exercise as measured by elevated mean RAP values.

Heart rate of Mangalarga Marchador mares under marcha test and supplemented with chrome

“…However, the use of Cr did not influence the HR values. These results are similar to those observed by Thomas et al (1983), who verified that, in rest, HR does not differ after training. Similarly, Evans (1994) affirmed that, in the equine at rest, HR does not usually decrease with training, as observed for human beings.…”

Effects of a submaximal treadmill training programme on histochemical properties, enzyme activities and glycogen utilisation of skeletal muscle in the horse

“…THE ability of equine skeletal muscle to accommodate changes in demand associated with training has been demonstrated during the last decade. Most studies have focussed attention on the changes in muscle composition of either Standardbred Trotters (Lindholm and Piehl 1974; EssCn, Lindholm and Thornton 1980; Taylor and Brassard 1981; EssCn-Gustavsson er a1 1983 ;Henckel 1983a) or Thoroughbreds and/or Heavy Hunters (Guy and Snow 1977a, b;Snow and Guy 1979; Nimmo, Snow and Munro 1982 Thomas and Fregin 1981; Thornton er al 1983), whereas others have examined the cardiovascular (Bayly, Gabel and Barr 1983) and cardiorespiratory (Thomas, Fregin, Gerber and Ailes 1983) responses of horses subjected to submaximal treadmill training programmes. However, there appear to be no reports of the changes occurring in equine skeletal muscle as a result of treadmill training.…”

Chromium or l-carnitine supplementation during an aerobic conditioning program mildly modified the energy metabolism biomarker response in Mangalarga Marchador fillies

“…According to Thomas et al (1983), heart rate during submaximal exercise usually decreases by 10 to 20 bpm after conditioning. The present study found a mean overall reduction of 11 bpm in HR between Test 1 (110 bpm) and Test 2 (99 bpm), while the latter was very close to the average of Test 3 (100 bpm).…”