Homeostasis  

Exercise places a physical stress on the body. The heart pumps faster and harder but what happens to the temperature and blood pressure ?

Do a literature search on the topic and briefly state what others have found. Include a bibliography.

Using "if" and "then" statements formulate a hypothesis as to how you expect temperature and blood pressure to respond to increase in heart rate due to physical stress.

Procedure.
Using the apparatus supplied, measure:
- both systolic and diastolic blood pressures at rest,
- temperature under the tongue
- heart rate
- surface skin temperature .
Do this at least twice or when three concordant results are obtained for each. Average the results.
Conduct a lengthy warm up.
Working in groups of two have your partner run a 100m sprint. This should be done at maximum pace.

When your partner is finished quickly, within 10 seconds, measure blood pressure and heart rate as well as core and surface temperature.

Record the result in the table on the right.
Activity Diastolic
(mmhg)		 Systolic
(mmhg)		 Surface
Temp. (oC)		 Core
Temp (oC)		 Heart rate
Rest          
100m          
200m          
300m          
400m          
The automatic blood pressure monitor shown on the right is very simple to use and makes accurate recordings. It gives the pulse rate, diastolic and systolic pressure readings all at once.
A thermometer is placed under the tongue to record core temperature. While a temperature sensitive patch is used to measure skin surface temperature.
The school oval can be used to conduct this activity. It should be obvious that the degree of stress placed on the body is getting progressively greater with each distance.

1) Can we have more than one dependent variable? What is/are the dependent variable/s in this investigation?
2) What is the independent variable?
Graph the results.

3) What do you conclude from your results?

i) Does blood pressure fluctuate? Offer an explanation for your observations.
ii) Does blood pressure increase proportionally to increase in heart rate? Offer an explanation for your observations.
iii) How do both the systolic and diastolic pressures change relative to each other?
iv) How does core temperature change as heat producing exercise takes place?
v) How does the skin temperature change? Explain this result.
vi) What is systolic pressure and diastolic pressure?
4) The greater the resistance to blood flow the greater the blood pressure in the arteries will be. Explain how resistance is controlled in small arterioles.
5) On a hot day, or after exercise, the colour of the skin on the face of a person changes to become more red. Explain why.
6) Do the results support your hypothesis? Explain
7) What is your conclusion.