Physiology, Health & Exercise

1. Physiology, Health & Exercise Lesson 4 Cardiac Output Resting Pulse Measuring Blood Pressure

2. Puzzle • If you have three oranges and you take away two, how many will you have?

3. Puzzle- answer • Two. The two you took.

4. Cardiac Output (CO) • Volume of blood pumped by each ventricle per minute • Related to • heart rate (HR) and • stroke volume (SV) • Measured in litres per minute CO = HR x SV

5. Cardiac Output (CO) Example • heart rate (HR) = 72bpm • stroke volume (SV) = 70ml • What is the CO? • CO = 72 x 70 = 5040ml/min • = 5.04l/min • As activity level increases CO also increases

6. Average Resting pulse • 60-100bpm • Fitter people have a lower resting pulse • E.g. very fit athletes--> 30-40bpm • Resting pulse decreases with age • As activity level increases pulse (& Heart rate) increases

7. Activity & CO Calculate the CO in each case

8. Activity & CO • What is the effect on the following as the work load increases • Heart rate? • Stroke volume? • What is the CO principally due to?

9. Blood Pressure (b.p.) • Measure of force of blood against the walls of the arteries • B.p. highest during systolic phase of cardiac cycle • B.p. lowest during diastolic phase of cardiac cycle • Measured using a sphygmomanometer and stethoscope

10. Blood Pressure (b.p.) • Measured as raising a column of mercury so units mm Hg. • Reported as 2 numbers • So if systolic is 140 mm Hg & diastolic is 85 mm Hg then: Systolic Diastolic 140/85

11. Blood Pressure (b.p.) • Systolic b.p. changes during exercise and can reach 200mg Hg • Diastolic b.p. remains approx constant • Measured using a sphygmomanometer and stethoscope

12. Blood Pressure (b.p.) • First- reading- Systole -when blood spurts through an artery as the pressure in the artery exceeds the pressure in the cuff • Second reading- Diastole- more air released from cuff- initially sounds are louder, then muffle and disappear as blood flows continuously through the artery • measuring blood pressure

13. Blood Pressure (b.p.) • Average healthy person range of values: 140- 100 90-60

14. Blood Pressure (b.p.)- changes • B.p. increases as age increases • B.p. decreases as age decreases • B.p. increases as heart is overworking • Elevated b.p.- hypertension one of the most common factors in the development of CVD (cardiovascular disease)

15. Raised Blood Pressure (b.p.) • Elevated b.p.- increases chance of atherosclerosis occurring • Hypertension- symptom less in early stages • however if it continues it puts an excessive strain on the heart & if untreated will cause heart failure