The Effect of Two Acute Bouts of Exercise on Oxidative Stress, Hematological, and Biochemical Parameters, and Rectal Temperature in Trained Canicross Dogs

Abstract

Canicross is a sport discipline that connects human and canine athletes in running. Changes in physiological, hematological, and biochemical parameters, and exercise-induced oxidative stress have not been thoroughly characterized in canicross dogs. The aim of our study was the assessment of the health status of trained canicross dogs that were subjected to two acute bouts of exercise with their owners during the training season. Health status was assessed by measuring the rectal temperature, hematological and biochemical parameters, as well as blood oxidative stress parameters (plasma malondialdehyde, lipid peroxidation marker; whole blood glutathione peroxidase and erythrocyte superoxide dismutase1, antioxidant enzymes) before and during a two-day canicross training session and after a 24-h rest period. Seven trained canicross dogs (three females/four males) aged 12–120 months were included in the study. Blood samples were collected before and immediately after the first acute bout of exercise (day 1), after the second acute bout of exercise (day 2), and after 24 h of rest (day 3). Rectal temperature was measured at the same time as blood sample collection. The majority of hematological and biochemical parameters remained within reference ranges at all sampling times. Rectal temperature was significantly higher after training on days 1 and 2 compared to resting temperature on day 3. Hematological parameters did not change significantly; however, there were significant differences in urea, creatinine, creatine kinase, and triglycerides between specific sampling times. Despite significant changes, these biochemical parameters remained within reference ranges. Significant changes in biochemical parameters seem to reflect the dogs' physiological response to each acute bout of exercise, considering all biochemical parameters and rectal temperature returned to pre-exercise values after a 24-h rest period (day 3). No significant differences in oxidative stress parameters were found between any sampling times. Relatively high erythrocyte superoxide dismutase1 activity at all sampling times may indicate that the canicross dogs are adapted to training by an increased expression of antioxidant enzymes. Based on our results, we can conclude that the trained canicross dogs included in our study were healthy, in good physical condition, and fit for the two acute bouts of field exercise.

Thermal relations in sled dogs before and after exercise

“…We hypothesized that the mean average in body temperature postexercise in sled dogs would be less than in nonathletic dogs, like findings from previous studies, while having an overall potential indirect relationship between body mass and core temperature (T ear ) (Erjavec et al, 2022; Hall & Carter, 2017; Williams et al, 2015). Furthermore, we hypothesized that T mouth , T eye , and T nose would show less dramatic thermal changes with exercise, but should be less drastic than thermal changes in nonathletic dogs of similar sizes.…”

“…We hypothesized that the mean average in body temperature postexercise in sled dogs would be less than in nonathletic dogs, like findings from previous studies, while having an overall potential indirect relationship between body mass and core temperature (T ear ) (Erjavec et al, 2022;Hall & Carter, 2017;Williams et al, 2015).…”

“…With a wide range of intraspecies variation in the correlation of body mass and whole animal and mass‐specific metabolic rates, dogs could serve as an interesting model system of how physiology and morphology affect thermoregulation (Jimenez, 2016). Defined synonymously within this paper, sled dogs and canine athletes are thought to possess physiological adaptations that allow them to conquer thermoregulatory demands at a higher efficiency than nonathletic domestic or sedentary dogs (Erjavec et al, 2022; Menchetti et al, 2019; Schneider et al, 2009). These adaptations create discrepancies between athletic and nonathletic dogs in their body temperature, heart rate and various hematological and biochemical parameters (Angle et al, 2009; Burr et al, 1997; Davis et al, 2008; Gabriel & Zierath, 2017; Kenny & McGinn, 2017; Pedlar et al, 2019; Robbins et al, 2017).…”

“…In general, nonathletic dogs have a higher body temperature postexercise, ranging from more than 2.15–2.70°C above basal temperature when measured after activity (Nazar et al, 1992). Contrastingly, athletic dogs saw a mean increase from basal temperature of 1.8°C and 1.5°C, a notably lower range than in nonathletic dogs, along with steady returns to normal temperature postexercise (Carter & Hall, 2018; Erjavec et al, 2022). This trend persists across human and canine athletes and is accompanied by an increase in heart rate and blood lactate concentrations (Gabriel & Zierath, 2017; Kenny & McGinn, 2017; Pedlar et al, 2019).…”

“…T ear , functioning as a proxy of core body temperature (T b ), was correlated in relation to body mass, morphology, and age. Overall, we hypothesized that the mean increase in body temperature after exercise would be less that nonathletic dogs, based on findings from previous studies (Erjavec et al, 2022; Hall & Carter, 2017; Jimenez et al, 2023). A reduced range of temperature flux may be due in part to the superior cooling methods, for example movement of heat and blood flow to the extremities, present in canine athletes to mitigate increased metabolic demands (Gunn, 1978; Pichová et al, 2023).…”