Physiology Health Exercise Lesson 4 z Cardiac Output

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

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

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

Cardiac Output (CO) z Volume of blood pumped by each ventricle per minute z Related to yheart rate (HR) and ystroke volume (SV) z Measured in litres per minute CO = HR x SV 4

Cardiac Output (CO) Example z heart rate (HR) = 72 bpm z stroke volume (SV) = 70 ml z What is the CO? z CO = 72 x 70 = 5040 ml/min z = 5. 04 l/min z As activity level increases CO also increases 5

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

Activity & CO Activity Level HR (bpm) SV (ml) Rest 72 70 Mild 100 110 Moderate 120 112 Heavy-highly trained athlete 200 150 Calculate the CO in each case CO (l/min) 7

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

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

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

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

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

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

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

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