The influence of training on resting blood pressure was investigated in rats assigned to normotensive (NTR), borderline hypertensive (BHR), spontaneously (genetic) hypertensive (SHR), or spontaneously hypertensive groups receiving anti-hypertensive drugs (SHR-D). Experiments were conducted for short (10-12 weeks) or long term (52-84 weeks) intervals with blood pressure measurements being obtained from the caudal and/or carotid artery of unanesthetized and anesthetized rats respectively. Changes in muscle enzyme activity, adipocyte diameter and submaximal heart rates were used to verify that the exercise program had produced a trained state. Training was associated with lower blood pressures in unanesthetized as well as in anesthetized NTR groups and in most comparisons these changes were statistically significant. With BHR and SHR groups, chronic exercise appeared to delay the onset of the hypertension as well as the magnitude of the pressure being developed. However, exercise was unable to normalize resting pressures in the SHR group. Anti-hypertensive drugs were administered to nontrained and trained SHR groups and pressure normalization occurred in both populations. Training was not associated with lower values in these investigations. Plasma and total blood volumes were measured in NTR groups and the trained rats had significantly larger volumes than their nontrained controls. Of interest was the finding that trained SHR groups had heavier heart weights than the nontrained SHR. The mechanisms responsible for these pressure changes are obscure and deserving of further investigation.
TRAINING AND HYPERTENSION, EXERCISE AND HYPERTENSION, EXERCISE AND BLOOD PRESSURE, TRAINING AND BLOOD PRESSURE, TRAINING AND SHR GROUPS, HYPERTENSIONS AND ORGAN WEIGHTS
Exercise Physiology Laboratory University of Iowa Iowa City, Iowa 52242
Submitted for publication January, 1977.
Accepted for publication June, 1977.