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Updated: Jul 6, 2026
Conducting Maximal and Submaximal Endurance Exercise Testing to Measure Physiological and Biological Responses to Acute Exercise in Humans
Published on: October 17, 2018
Effects of training and strenuous exercise on hematologic values and peripheral blood leukocyte subsets in racing
Michael S Davis1, William C Davis, Wayne Y Ensign
1Comparative Exercise Physiology Laboratory, 264 McElroy Hall, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK 74078, USA.
Objective:
To determine the effects of training and sustained submaximal exercise on hematologic values in racing sled dogs.
Design:
Cohort study.
Animals:
39 Alaskan sled dogs bred for endurance racing. Procedures-Blood samples were collected prior to initiation of a 7-month training regimen (n=39), after completion of the training regimen (19), and after completion of an 1,100-mile race (9), and a CBC, differential cell count, and flow cytometry for leukocyte surface antigens were performed.
Results:
Both training and exercise caused significant decreases in PCV and hemoglobin concentration and significant increases in total WBC count. In contrast, training and exercise were not found to have significant effects on absolute numbers or fractions of CD4+ or CD8+ lymphocytes, other than a significant increase in the fraction of CD8+ lymphocytes associated with training.
Conclusions And Clinical Relevance:
Results suggested that training and exercise induced changes in several hematologic values in racing sled dogs. Extracellular fluid volume expansion was the likely explanation for the training-induced decrease in PCV, and acute blood loss secondary to gastrointestinal tract bleeding was likely responsible for the decrease in PCV associated with acute exercise.
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