Cardiovascular and Respiratory Responses to Submaximal Exercise under Aerobic Conditions

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University of Hertfordshire

Faculty of Health and Human Sciences

Department of Nursing and Paramedic Sciences

Integrated Biosciences for Paramedics

Module Code 1ANN0002 Semester B

Laboratory Report

Cardiovascular and Respiratory Responses to Submaximal Exercise under Aerobic Conditions

Michael A Jones

Submission date 30 May 2003         

1. Introduction

Cardiovascular and respiratory mechanisms must work in a combined fashion to support the oxygen (02) needs of exercising tissue, and to eliminate from the body the waste products that are brought about by increased cellular metabolism, namely heat and carbon dioxide (C02), thus maintaining homeostasis.

In order to record the body’s cardiovascular and respiratory response to exercise, the cohort was split into sub-groups where two from each sub-group were measured   for their physiological changes during a period of rest, a period of submaximal exercise, and a recovery period.

During exercise the body’s demand for (02) is increased to maintain adequate tissue cell perfusion, and as a result of this the cardiovascular system responds by increasing heart rate (HR)

The respiratory systems response to exercise as stated by (Wetter T. et al 2000) is that

“as exercise intensity increases from mild to moderate effort, alveolar ventilation must increase proportionally to prevent a build up of (CO2)  which would soon acidify the arterial blood” .

This increase in (C02) is picked up by central chemoreceptors  which in turn send sensory impulses to the respiratory centre in the brain stem to increase the rate and depth of ventilations, therefore excreting excess (CO2) and maintaining the acid base balance.

The metabolic rate increases as the body moves from rest to exercise thus requiring an increase of adenosine triphosphate (ATP) resulting in increased heat production. The amount of heat produced during exercise should equal the amount of heat loss to maintain a constant core temperature of 370C, therefore maintaining a homeostatic state. On sub-maximal exercise there will be a rise in (HR), a rise in end tidal (ETCO2) and a minimal change in body temperature.

2. Materials and Methods

The laboratory protocol was followed exactly. Please see appendix A.

3. Results

All testing was completed under conditions that were as carefully controlled as possible. The laboratory was not controlled with regard to temperature, although it remained constant through the experiment at 24 0 C. It was noted after ten minutes that there was incorrect use of the tympanic thermometer by subject (B).

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Figure 1.1 and 1.2 shows that in subjects (A) and (B) as production of (ETC02) rises, the respiratory centre is stimulated and therefore increases the respiratory rate to expel the excess (C02) and so maintaining a homeostatic state. After this sudden increase in ventilation, a brief pause is noticed prior to a further increase to steady state exercise.

 It also can be seen that as sub-maximal exercise is stopped there is an abrupt decrease in respiration followed by a gradual increase to normal resting values. The overall trend appears to support the above and is shown in the raw data ...

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