Physiology, Health & Exercise Lesson 4 zCardiac Output zResting Pulse zMeasuring Blood Pressure

2 Puzzle zIf you have three oranges and you take away two, how many will you have?

3 Puzzle- answer zTwo. The two you took.

4 Cardiac Output (CO) zVolume of blood pumped by each ventricle per minute zRelated to yheart rate (HR) and ystroke volume (SV) zMeasured in litres per minute CO = HR x SV

5 Cardiac Output (CO) Example zheart rate (HR) = 72bpm zstroke volume (SV) = 70ml zWhat is the CO? zCO = 72 x 70 = 5040ml/min z = 5.04l/min zAs activity level increases CO also increases

6 Average Resting pulse z60-100bpm zFitter people have a lower resting pulse zE.g. very fit athletes--> 30-40bpm zResting pulse decreases with age zAs activity level increases pulse (& Heart rate) increases

7 Activity & CO Activity LevelHR (bpm)SV (ml)CO (l/min) Rest7270 Mild Moderate Heavy-highly trained athlete Calculate the CO in each case

8 Activity & CO zWhat is the effect on the following as the work load increases yHeart rate? yStroke volume? zWhat is the CO principally due to?

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

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

11 Blood Pressure (b.p.) zSystolic b.p. changes during exercise and can reach 200mg Hg zDiastolic b.p. remains approx constant zMeasured using a sphygmomanometer and stethoscope

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

13 Blood Pressure (b.p.) zAverage healthy person range of values:

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

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