Cvs in Dynamic Exercise

Introduction

Blood pressure is defined as the force exerted by circulating blood against the walls of blood vessels (Guyton & Hall, 2006). It is divided into two components namely systolic pressure (contraction phase) as well as the diastolic pressure (relaxation phase). Blood pressure is dependant on heart rate (number of times the heart contracts per minute), stroke volume (amount of blood ejected from the ventricles during systole ≈ 70ml) as well as total peripheral resistance (resistance experienced by blood on the periphery).

Mean Arterial Pressure (MAP) is the average pressure responsible for driving blood forward into the tissues throughout the cardiac cycle. MAP must be closely regulated; it has to be high enough to ensure sufficient driving force; but not high enough that it places extra strain on the heart. MAP is constantly monitored by the baroreceptors which initiate multiple responses to restore the MAP to normal. This is accomplished by changing CO (by changing HR and SV) and TPR. Mean arterial pressure = Cardiac Output x Total Peripheral Resistance

The aim of this experiment is to ascertain the effects of exercise and posture on blood pressure and heart rate. This will be done by critically analysing the data obtained whilst the subject was at rest, whilst standing and also whilst exercising at different intensities.

Equipment

1. Bp cuff known as a sphygmomanometer which measures blood pressure in mmHg

2. Stethoscope (single lumen ) which amplifies sounds when placed on the body

3. Stop watch to measure pulse as well as timing during exercise

4. Bleeper which controls the different intensities of exercise

Methods

Measurement of Blood Pressure

Safety Notes:

• The cuff must not be left inflated for periods of time longer than 2 minutes or if the subject experience pain in the arm

• The subject's arm must be allowed to recover for at least 3 minutes between each inflation of the cuff

• In the event that the digits go cyanotic immediately release the cuff and ensure that the hand is below the heart level to ensure reperfusion

Method

• The subject should fully uncover one arm

• The arm should be held extended at the elbow with the forearm supported on the bench. The muscles should be relaxed.

• Locate the pulse of the brachial artery

• Wrap the cuff around the upper arm with the marked