Acute and chronic physiological changes to high intensity training
Date
1986
Authors
Doyle, Patricia K.
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Abstract
Six healthy male varsity oarsmen from the University of Victoria volunteered to participate in a 14 week training program. This study was designed to investigate the acute and chronic responses of hemoglobin (Hb), hematocrit (Hct), white blood cell (WBC), and creatine phosphokinase (CPK), to a 4 week control period and an 8 week training program of increasing intensity and to relate these to changes in a performance test (PT). Mean maximum oxygen consumption (Vo2max) increased from 4.4 ± 0.1 to 4.9 ± 0.1 1-min-1 and body weight and skinfolds decreased significantly during the study. No change occurred in maximal or recovery heart rates. The chronic response of Hct showed a 4 % decrease during both the control period (weeks 1-4) and over weeks 5-8 of training but increased 4 % from weeks 9- 13. Hb decreased 7 % during weeks 1-4 and a further decrease of 1.9% occurred during weeks 5-8. The acute values of Hct and Hb were slightly smaller than the chronic values but followed similar trends. The mean difference between the chronic and acute values during the weeks of training was 2.4 % for Hct (48.5 ± 0.9, 47.6 ± 0.9 %) and 2.9 % for Hb (14.6 ± 0.97, 14.5 ± 0.4 g·dC 1) respectively. The only significant changes in WBC occurred in the acute fluctuations of the chronic response. CPK increased from week 1 to week 13 both chronically (63.9 ± 0.9 to 98.9 ± 0.4 U•C1) and acutely (63.7 ± 1.3 to 109.0 ± 1.3 U·C1). Weeks 5-8 showed the greatest change with a two fold increase in the chronic (129.9 ± 1.2 U•C1) and a four fold increase in the acute response (253.7 ± 2.3 U•C1). All subjects improved in the PT over the 13 weeks with the greatest improvement occurring between weeks 4-7 (p<0.05). In conclusion the acute and chronic responses of Hct and Hb elicit similar changes to repeated bouts of training (r=0.571). CPK levels in venous blood were significantly different in the acute and chronic response to exercise. This study was not able to demonstrate a decrease in the PT with changes in the acute and chronic levels of Hb, WBC, and CPK. However, a decrease in Hct was related to an increase in performance despite the low N and homogeneity of the sample (r=0.340).