Cardiac efficiency tests (CET)Exercise tolerance

tests(ETT)Stress testing

The efficiency of Cardiac performance can be determined by :(1) Subjective symptoms like pain and Dyspnoea(2) Clinical examination of heart.(3) Radiological examination of heart.(4) Electrocardiography(5) Echocardiography(6) By performing CARDIAC EFFICIENCY TESTS - Efficiency of circulation lies in giving a prompt response to a sudden stress and returning back to the resting condition as soon as the stress is removed.

Cardiac efficiency testsThe response of the CVS to standardized exercise is the single best test for assessing the heart efficiency – physical fitness

Any extra activity over the resting basal level like muscular exercise, demands additional nutrition as well as faster removal of metabolic end products.

To meet this demand, there is a progressive ↑ in the HR & BP. These values return to the pre – exercise levels during the next few minutes after the exercise is over.

Cardiac efficiency testsThe extent of increase in heart rate as well as time taken by the heart to return to basal level will give an idea about the cardiac efficiency of the subject.

The basis of ETT – Compared to a trained person (athlete), there is a greater ↑ in the HR & BP in an untrained individual, and these values take a longer time to return to basal levels.

The response depends on – cardiac reserve, muscle power, training, motivation, nutritional state. Therefore, Cardiac efficiency can also be used to test physical fitness of an individual.

Hopping testPro.:Recording of basal pulse rate – hopping on each foot 20 times

Response:In healthy heart, little disturbance of breathing,HR not ↑ by more than 10 – 20 bpm,Return to pre – exercise level in about a minute

Harvard Step Test**** Only for physical fitness, not be used in patients

Pro.: After recording basal pulse rate, subject should step up & down a 50 cm bench (40 cm for females), at a frequency of 30 times/min for 5 minutes

Stop the test if the subject feels breathless and exhausted and unable to continue the test.

Count the pulse rate 1 minute after the end of the exercise

The pulse rate is inversely proportional to the degree of cardiac efficiency

Cardiac efficiency indexCount the pulse rate at

Between 1 & 1.5 minutes = _____ / min (A)Between 2 & 2.5 minutes = _____ / min (B)Between 3 & 3.5 minutes = _____ / min (C)

Cardiac efficiency index = Duration of exercise in seconds (300)

________________________________ x 100 A + B + C

Cardiac efficiency indexIn normal individuals, the index is nearly 100 %, but is more in sport persons

Efficiency index:

Over 90 % : Excellent81 – 90 % : Good55 – 80 % : AverageBelow 55 % : Poor

Grading of exerciseWHO grading of muscular exercise:

VO2 Max: Maximum amount of O2 that can be consumed during a severe exercise.

Resting VO2 ( O2 consumption ) = 250 ml/min.

Grade HR (bpm) O2 consumption (L/min)

RLI MET

i. Light (mild)

< 100 0.4 – 0.8 < 25 < 3

ii. Moderate 100 - 125 0.8 – 1.6 25 - 50 3.1 – 4.5

iii. Heavy 125 - 150 1.6 – 2.4 51 - 75 4.6 - 7

iv. Severe > 150 > 2.4 > 75 > 7

Cardiac reserveIt is the difference between the basal CO of an individual & the maximum CO that can be achieved in that person.

Cardiac reserve % =

Maximum CO – Basal CO ______________________ x 100 Maximum CO

- Every Organ in the body, including heart, has a reserve capacity which the body draws upon in case of emergencies. - This reserve capacity diminishes in pathological situations and this decreases the efficiency of the Organ.

Cardiac reserveAny factor that prevents the heart from pumping blood satisfactorily decreases the cardiac reserve.

(i) Ischemic Heart Disease.(ii) Primary Myocardial Disease.(iii) Vitamin Deficiency.(iv) Valvular Heart Disease.(v) Myocardial damage

Causes of ↑ HR during exercise(1) Increased sympathetic activity – anticipatory

tachycardia.

(2) Decrease in Vagal tone.

(3) Increased activity of the limbic system and motor cortex due to psychic stimuli directly acting on medulla – anticipatory tachycardia.

(4) Increased Peripheral reflexes originating from(i) Muscle spindle(ii) Muscle tendon receptors(iii) Joint receptors(iv) Organ of Corti

Causes of ↑ HR during exercise(5) Liberation of hormones into circulation (Centrally acting)(i) Catecholamines from Adrenal Medulla (ii) Thyroxin (T4)from thyroid gland in response to stress

(6) Increase in body temperature.

(7) Chemical changes occurring in the bloodHypoxia - arterial PO2Hypercapnia - arterial PCO2AcademiaLactic Acidosis - pH

Indications(A) PHYSIOLOGIST has been interested in (1)To Assess the work capacity of healthy individuals.

(2)To determine the physical fitness of population groups.

(3)To improve the performance of athletes, sportsmen and military personnel.

Indications (B) PHYSICIAN has been interested to use these tests as (1) In Aiding the diagnosis of heart and lung disease.(2)Pre and Post - operative assessment of cardio thoracic surgical patients.(3) Rehabilitation of Cardiac individuals.(4) Screening workers for disability compensation.- The exercise tolerance tests are the best tests for determining the efficiency of the heart as a pumping organ.- These tests take the place of cardiac output measurements which cannot be made with ease in most clinical settings.

PHYSICAL FITNESS- A person is considered to be fit for a particular task or activity if he accomplishes it with a reasonable degree of efficiency without, being fatigued and with rapid recovery from the effects of that exertion.- Thus physical fitness is a relative term and it is impossible to make an absolute distinction between fitness and unfitness. COMPONENTS OF PHYSICAL FITNESS : (A)Anatomical Fitness (B)Physiological fitness(C)PSYCHOLOGICAL FITNESS

(A)Anatomical Fitnessi.e. Height, weight and other measurements

- When all the organ parts of the body which are essential for the task are functionally present, an individual can be considered as anatomically fit.

- A man without a leg may not be a runner but can do lot of other things.

(B)Physiological fitness - It means the capacity of an individual for the skillful performance of the task along with rapid recovery.

- It includes muscular strength, motor skill, endurance etc.. A man with a weak masculine lacks capacity for doing a work requiring muscular strength but may acquire high degree of motor skill.

PSYCHOLOGICAL FITNESS - It depends upon the moral and religious training of the individual and the impact of the social and economic environment upon his life.

- It implies the necessary emotional stability, drive, motivation, intelligence and desire to learn to perform a task.

CONTRA INDICATIONS FOR EXERCISE TESTING

1. Loco motor disturbances

2. Musculoskeletal dysfunctions

3. Anxiety

4. Ischemic Heart Disease

5. Unstable metabolic conditions

6. Threatening signs of Heart failure

OTHER CARDIAC EFFICIENCY TESTS

(I)MASTER'S STEP TEST

(II)TREAD MILL TEST

(III) BICYCLE ERGOMETRY

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