Abstract
Summary
In order to analyze the effect of age, a study was made of the hemody-namic responses of three groups of normal male subjects (19 to 26, 40 to 49, and 47 to 56 years) to 70° head-up tilt and to the valsalva maneuver. Compared to the youngest group the two older groups showed a marked diminution in heart rate, diastolic pressure, and mean arterial pressure responses to head-up tilt, and lesser heart rate changes in the different phases of the valsalva tests. There was very little intertest correlation between the circulatory responses to the two stresses. These alterations in response with advancing age may be related to altered baroceptor sensitivity or to diminished blood pressure changes associated with decreased venous compliance or increased central blood volume. The results indicate that consideration must be given to the age effect when assessing circulatory responses to the tilt and valsalva in the human.
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