Phys

Cardiovascular Effects of Exercise

This basic experiment allows students to see how exercise affects the ECG and the finger pulse.

Written by staff of ADInstruments.[pic]

Introduction

In this laboratory session you will record the electrocardiogram (ECG) and the finger pulse from a healthy volunteer, and compare the recordings made when the volunteer is at rest and immediately after exercise.

Background

The arterial system functions as a pressure reservoir. Blood enters via the heart and exits through the capillaries. Signals from the autonomic nervous system control the tone of smooth muscle sphincters around the arterioles. In this way, the autonomic nervous system can control the distribution of blood to the various organs in the body. The distribution of blood that flows to a particular organ is influenced by local conditions. If there are cells that require more arterial blood, due to a decline in pH or oxygen levels or an increase in carbon dioxide levels, smooth muscle sphincters open to permit blood into particular capillary beds.

The distribution of blood to a particular organ when a subject is at rest may be very different from that seen during exercise. For example, the blood flow to the skin and the gut decreases during exercise, while blood flow to the skeletal muscles increases dramatically. Furthermore, the amount of blood flowing around the circulatory system (the cardiac output) may be increased to many times its resting value.

Required Equipment

A Computer system

Chart software, version 5.0 or later

PowerLab (with built-in Bio Amp or PowerLab and Bio Amp front-end)

Five-lead Shielded Bio Amp Cable & snap-connect Lead Wires

Three reusable clamp electrodes or disposable adhesive electrodes

Electrode cream (for use with the clamp electrodes)

Alcohol swabs (70% ethanol on cotton wool or paper tissue); optional

Ballpoint pen

Abrasive pads/gel

Finger pulse transducer

Hand dynamometer or a rubber squeeze-ball (e.g....