Question

1. Construct a hypothesis indicating how you anticipate the body's heart rate and blood pressure to respond to postural changes.

Answer 1

The change in arterial blood pressure is one of the generally known physiological changes in aging of man. Many factors are responsible forthe rise of blood pressure of which age is one of the factor. As in the process of aging the structural, functional, and biochemical changes occur with the influence of various genetic and environmentalfactors. When body position is changed from a supine or sitting position to standing. Pooling of blood in lower extremities occur due to gravitational effects. It reduces venous return and stroke volume with a fall in systolic blood pressure. Then Short Term regulatorymechanism(baroreceptor reflex) is operated to maintain normal Blood Pressure. This hemodynamic homeostasis becomes less effective with aging and is associated with a decreased ability to regulate blood pressure. Orthostatic Hypotension is a common clinical disorderamong the older population.Orthostatic blood pressure (OBP) is a measure of cardiovascular reactivity reflecting autonomic function. 2 Due to age related physiologic changes, the response of the sympathetic systemis usually decreased.Hence elder people tend to be more vulnerable to orthostatic stress than the younger ones. Also such elder ones having some associated diseases like hypertension, diabetes mellitus, and low blood volume become further weaker. 3 The primary purpose of thisstudy isto observe the postural variation of heart rate and blood pressure and to compare in different age groups

Measurement of Blood Pressure Response to Change in Posture

The measurement of postural change in blood pressure was conducted by a trained and certified technician. Supine and standing blood pressures were measured by using a Dinamap 1846 SX oscillometric device and a dedicated microcomputer. Details of the measurement of blood pressure can be found in ARIC Manual 11: Sitting Blood Pressure and Postural Changes in Blood Pressure and Heart Rate.¹¹Supine measurements of blood pressure and heart rate were taken after the participant had lain on the examination table during the ultrasound examination for a minimum of 25 minutes. Heart rate was measured on a beat-to-beat basis, and blood pressure was determined approximately every 30 seconds. The computer collected these data for 2 minutes. After the supine data were collected, the participant immediately stood and additional blood pressure measurements were taken for 2 minutes at ≈30-second intervals to assess the cardiovascular response to change in posture. Participants were instructed to bend their elbows and to hold their hands over the midriff in a comfortable position to prevent the cuff from sliding, to distract the participant, and to place him or her in a standard and comfortable position.