Tolerance to physical activity, or physical performance, is a summary indicator of the physiological capabilities of the body. It differs significantly among women and men, young people and older people, physical and mental work.
Among the homogeneous population, physical performance will vary depending on the weight and height of the patient. The higher the weight and height, the higher the tolerance for physical activity, provided that the main component of the weight is muscle mass and not subcutaneous fat.
In addition to these indicators, physical performance is affected by the functional state of other body systems (respiratory system, blood system, musculoskeletal system).
Currently, the assessment of tolerance to physical activity is carried out in various contingents of healthy people: conscripted into the armed forces and military schools, athletes, people of different ages, engaged in physical improvement. In the case of persons with cardiac pathology, tolerance for physical activity is determined in the following cases:
- In case of CHD to assess the adequacy of antianginal therapy, the effectiveness of rehabilitation measures in the post-infarction period, examination of working capacity.
- In neuro-circulatory dystonia (NDC), myocardial dystrophy, post-myocardiac sclerosis for objective assessment of the degree of tolerance to physical activity.
- At the got defects of heart for the control of efficiency of operative treatment on increase in tolerance to physical activity in comparison with the preoperative data; for an estimation of efficiency of operations of revascularization of a myocardium: aortocoronary bypassing and coronaryangioplasty.
- To predict cardiovascular complications in the postoperative period in elderly people, i.e. assessment of perioperative risk.
- Assessment of physical performance of cardiac patients and persons with mystpatology at referral to the medical and social expert commission.
Types of ergometry depending on the purpose of the study.
- Sub-maximum or maximum diagnostic test to confirm or exclude CHD.
- Sub-maximum or maximum exercise tolerance test.
- Provocative test to detect latent rhythm disorders.
- Multi-purpose test (1, 2), (2, 3) with priority target selection.
Multipurpose tests include paired and early ergometry, where previous examinations or myocardial infarction have shown that coronary pathology is undisputed and its confirmation is not a priority research objective. It is more appropriate to formulate a medical opinion, such as a physical activity test, in such cases.
In terms of power, the load can be either sub-maximum (the heart rate achieved should be between 75% and 90% of the maximum heart rate) or maximum, i.e. the maximum heart rate for a given age and gender. Normally, a sub-maximum load level is performed for a diagnostic test or an exercise tolerance test, i.e., the heart rate is usually 85-90% of the maximum heart rate.
A common formula for determining the maximum pulse rate is: Heart rate mah = 220 – age of the patient.
According to the American College of Cardiology and the American Heart Association (AHAC/AHA), the formula should be corrected accordingly: heart rate mah = 220 – age + 12 beats. R. Sherard (1969) proposed the following sub-maximal heart rate values for exercise samples by sex, weight and age, as recommended by the WHO Expert Committee.
Types of loads.
Different types of loads are applied depending on the purpose and the target population.
A sample may be conducted in a staggered increase in load with rest breaks after each step, or with an increase in load, but without rest breaks (staggered, continuously increasing) a staggered, continuously increasing sample with a duration of each step of 3 minutes is common practice in cardiology.
Testimony and contraindications.
- Presence of clinical signs of angina for objective confirmation of the functional class of angina.
- Presence of “risk factors” of CHD in asymptomatic persons without pain syndrome or with atypical pain syndrome.
- Presence of nonspecific changes of ST-T for ECG in persons without pain syndrome, preserved after the sample with hyperventilation, with potassium, oxidized or potassium-obzidanate.
- Selection of antianginal therapy in persons with a documented diagnosis of CHD (“paired” VEM).
- Evaluation of prognosis in early post-infarction period (“early” VEM).
- Control of rehabilitation measures in the post-infarction period on the dynamics of tolerance to physical activity at inpatient, sanatorium and outpatient stages of rehabilitation.
- Evaluation of the effectiveness of myocardial revascularization operations (balloon angioplasty, aortic-coronary, mamarocoronary bypass surgery).
- Assessment of tolerance to physical activity in persons with non-coronary cardiac pathology (myocardial dystrophy, post-myocardiac cardiosclerosis, heart defects, NDC, hypertension before and after treatment).
- Assessment of tolerance to physical activity in persons with extracardinal pathology to study the functionality of the cardiovascular system in the referral to surgical treatment or for the purpose of examination of work ability.
- Acute myocardial infarction in the first 2 weeks of the flow.
- First-time onset of angina-induced angina pain accompanied by local ischemic depression of VT and/or local negative T depths ³ 1mm. at least in two consecutive leads.
- Unstable angina, including progressive and variant angina, with unbought pain syndrome.
- Serious rhythm disorders and sinus tachycardia over 100 beats per minute.
- Severe circulatory failure (PB and III).
- Acute pericarditis.
- Acute and subacute septic endocarditis.
- Acute myocarditis.
- TEPA, heart clots, lung infarction, severe respiratory failure.
- Severe aortic stenosis.
- Acute or severe extrahearthen diseases (including those accompanied by an increase in body temperature).
- Aortic dissection aneurysm.
- Stage III hypertension within b months after a stroke.
In a specialized cardiac facility (department), patients with first-time, progressive or variant angina are not patients earlier,
within 72 hours from the moment of onset of attacks and within 48 hours after relief of pain syndrome and ischemic ECG changes, VEM is performed “on drugs” in order to assess
the effectiveness of antianginal therapy and the determination of further patient management tactics. The study is carried out according to the protocol of “early” sub-maximum loading test, described in the section of early tests in case of acute respiratory viral infections.
- Heart rhythm disorders (frequent extrasystoles, frequent paroxysms or constant atrial fibrillation, frequent atrial tachyarrhythmic paroxysms in people with organic heart diseases).
- Moderate arterial hypertension (ADH >170 mmHg, ADH >130 mmHg) and pulmonary hypertension with increased systolic pressure in the pulmonary artery ³ 60 mmHg.
- Moderate non-cardial diseases.
- Moderate valve defects and myocardial disease.
- Postinfarction left ventricular aneurysm with ventricular fibrillation and clinical death in history.
- Acute cerebral circulation disorder (CVMD) more than 6 months ago, syncopal states of unspecified etiology in the history.
- Endocrine diseases (diabetes, thyrotoxicosis, etc.).
- Hypertrophic cardiomyopathy.
- Psychoneurotic disorders.
- Medicinal allergy with Quinke’s edema, worsening during asthma, marked electrolyte disorders with changes in the original ECG.
- Conductivity disorder (complete atrioventricular blockade, blockade of Gisa beam legs, GPS syndrome).
- Severe anemia.
- Severe obesity (S-IV degree).
- Use of some drugs (foxglove, B-blockers, cordaron, prednisolone, diuretics).
- Diseases of the joints, nervous and neuromuscular systems that interfere with the sample.
Some relative contraindications may be temporary (electrolyte disorders, glycosides, B-blockers, cordaron): after 48-72 hours and, subject to the normalization of the original ECG, such VEM patients are performed in the usual manner.
For other relative contraindications (heart rhythm disorders, heart valve defects, myocardial diseases, left ventricular postinfarction aneurysm, atrioventricular blockages) VEM should be carried out in a specialized cardiological institution (department) with a clear definition of the purpose of the study.