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INTRODUCTION
Sports medicine should be understood more broadly then the traditional understanding the topic.
20 years ago: to be a "health serviceman" for top sportsmen, preventing and rehabilitating athletes from their sports - related injuries or modifying their training in order to prevent the overload.
Now: our primary focus is different: we try to exploit the fundamental relationship between functional capacity and health. The last 3 decades have brought ever-growing interest in exercise as a means to health, particularly cardiac and "metabolic" health with enthusiastic participation by both clinically healthy individuals (primary prevention) and by patients with various types of cardiovascular and metabolic disorders (secondary prevention + exercise therapy).
Despite the excellent practical results of non-pharmacological intervention in many groups of patients, the scientific evidence supporting adoption of an active lifestyle remains surprisingly incomplete.
Thus, after a basic propedeutical information we try to give you a practical basic knowledge in the field of exercise testing and exercise prescription in both primary and secondary prevention namely of "civilization diseases".
I) PROPEDEUTICS OF EXERCISE MEDICINE:
A) EXERCISE = FORM OF STRESS
Atributes for exercise description
SUBJECTIVELY HEAVY EXERCISE - SUBJ. MODERATE EXERC.
OBJECTIVELY HEAVY - OBJECTIVELY MODERATE
EMOTIONALY NEUTRAL - EMOTIONALY NEGATIVE .
PLEASANT - UNPLEASANT .
STATIC = ISOMETRIC - DYNAMIC = ISOTONIC E.
CONCENTRIC - EXCENTRIC CONTRACTION
CONTINUOUS - INTERMITENT EXERCISE
AEROBIC - ANAEROBIC
POSTURAL MUSCLE CONTR. - PHASIC MUSCLE CONTR.
BIG MUSCLE GROUP - SMALL MUSCLE GR. WORK
SHORT TERM EXERCISE - ENDURANCE EX.
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b) Energy:
Gross energy
1kcal = 4,2 kJ
In terms of heat of combustion
fats ............................ 9,3 kcal/g
carbohydrates............ 4 kcal/g
proteins...................... 5 - 6 kcal/g
coefficient of digestibility
caloric value of a meal
glycemic index
Energy stores
ATP , ADP, AMP
CP
Sacharides
Glucose for anaerobic glycolysis: short term energy
Glucose for aerobic glykolysis
Body fat..... 18C molecule of FFA .....146 ADP phosphorylations to ATP
Speed of fat utilisation is dependent on
* intensity, type and duration of exercise
* fat content of diet (adaptation)
* genetic dispositions
Lipids burn in a carbohydrate flame
Proteins: deamination loads the body with further demands for water
Glucose - alanin cycle.
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oxygen deficit, oxygen debt
contemporary concepts:
Excesive Postexercise Oxygen consumption (EPOC)
In numbers:
let us have intensive exercise at intensity of 70 % of max. inensity
If it lasts 20 minutes, EPOC during next 3 hours ... 7 L
If it lasts 40 minutes, EPOC during next 3 hours ... 10 L
If it lasts 20 minutes, EPOC during next 3 hours ... 15 L
15L of oxygen represents in 70 kg person his (her) oxygen consumption at the level of basal metabolism for one hour.
+ 0,1 to 0,2 C higher basal temperature next 3 - 24 hours..
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Optimal recovery from intermitent exercise:
moderate coninuous dynamic exercise
Contribution of aerobic and anaerobic metabolism to maximal exercise
TIME [min] 0,2 0,5 1 2 4 10 30 60 120
% ANAEROBIC 90 80 70 50 35 15 5 2 1
% AEROBIC 10 20 30 50 65 85 95 98 99
C) Basic equipment of exercise testing lab for medical purposes:
* dynamic load sources: bicycle ergometer treadmill, bench-step
Use: to load a patient with dynamic exercise according to adequate protocol
bench - step:
+ low cost, no maintenance, no calibration, easy habituation
- only for submaximal testing, ancillary measurements difficult
ergometer
+ effort is less dependent on patient's will
+ good reproducibility,
+ maximal load possible (but the maximal heart rate as well as the maximal oxygen consumption is usually about 10 % lower then in the identical person loaded at the treadmill)
+ easy tracing of EKG, blood pressure, gas exchange variables (oxygen consumption, minute ventilation, carbon dioxide production, respiratory exchange ratio)
- needs calibration
- impossible to use in patients with limited mobility
treadmill
+ best for maximal tests
- noisy
- costly
- ancillary measurements difficult
* static load source : handgrip for dosage of forced contraction (or, in special cases, controlled muscle group contraction with measurement of force using tensometer)
* EKG
Use: accurate heart rate measurement
arrhythmias detection
myocardial ischemia detection
* blood pressure monitor : ( preferably the classical mercury manometer )
Blood pressure reaction during and after exercise.
( ! If you are not able to measure the blood pressure during dynamic exercise, you have no more than 5 beats after patient stops for assessment of the systolic blood pressure, as for blood pressure and static exercise it must be measured during and NOT AFTER the test )
* lung function test equipment (flow - volume curve)
* pulse oxymeter
* set for the first aid: oxygen source, defibrilator, pharmacologic aid
II) MEDICAL INDICATIONS FOR EXERCISE TESTING
A) Diagnostic exercise testing
* Early diagnosis of
- lower coronary reserve
- exercise induced symptoms
(arrhythmias, postexercise bronchospasm, metabolic disorders)
B) Functional testing
a) Fitness testing for
* risk stratification
Low aerobic capacity is one of the moderate risk factors of coronary heart disease - the main ones are ordered approximately as follows: age - family history - cigarette smoking - hypertension - lipid profile -
low insulin receptor sensitivity - obesity - sedentary lifestyle
* severity of disease
Aerobic capacity - measured directly by oxygen consumption or indirectly by ability of patient to sustain exercise with increasing load - is relatively reliable marker of patient's disability.
b) Specific functional testing for:
* adequacy of pharmacotherapy
* non - pharmacological intervention (= cardiac rehabilitation) in patients with " civilization diseases "
* cardiology
MAIN CONTRAINDICATIONS FOR EXERCISE TEST
1) Any sign of acute cardiac event (for example resting EKG signs of severe myocardial ischemia - resting ST segment displacement >2 mm
2) Unstable angina pectoris anamnestically
3) Uncontrolled ventricular (or some other severe) arrhythmias, uncontrolled sinus tachycardia (>120 beats/min), third degree A - V block (without pacemaker)
4) Signs of severe impairment of cardiac function at rest (acute congestive heart failure, dyspnea)
5) Signs of deep vein thrombosis or thrombophlebitis
6) Recent systemic or pulmonary embolism
7) Acute infections
8) Active or suspected myocarditis
9) Resting SBP >200 mm Hg or resting DBP >110 mm Hg should be evaluated on a case-by-case basis
10) Significant emotional distress
11) Uncontrolled metabolic disease or endocrinopathy
12) Relative contraindications: any disease, that can be exacerbated by inadequate exercise (muskuloskeletal disorders, chronic infectious dis., uncompensated chronic heart failure)
GENERAL INDICATIONS FOR INTERRUPTION OR STOPPING THE EXERCISE TEST
1) Progressive fatigue
2) Substantial discomfort due to dyspnea, pain or emotional stress
3) Drop in systolic blood pressure or failure to increase the pressure with increasing exercise intensity
4) Excessive rise in blood pressure :
systolic blood pressure > 240 mmHg in patient above 40y.
> 250 mmHg in young sportive pat.
diastolic blood pressure > 120 mmHg
5) Signs of poor perfusion: pallor, confusion, ataxia, nausea , cramps
6) Progressive ECG pathology: severe arrhythmia (multifocal ventricular isolated premature beats, run of ventricular tachycardia, R on T etc.
ST segment depression
7) (in children) : anxiety of parents to increase the load
III) Exercise THERAPY
(exercise prescription)
Leading idea of last decades was: only two main categories of people need careful and precise exercise prescriptions: athletes and those who have a disease that adversely affects their physical capacity. This idea (after subtracting top athletes care) is the basis for secondary prevention strategies in exercise prescription.
These years a new strategies of "exercise encouraging“ were developed also for primary prevention based on terms as wellness, healthier way of life, general fitness.
There is not a sharp border between these two types of prevention (and even between prevention and therapy), especially for patients with signs of metabolic syndrome
Insulin resistance syndrome = METABOLIC CARDIOVASCULAR SYNDROM
(= METABOLIC SYNDROM ,=SYNDROM X,=DEADLY QUARTET )
- fuzzy group of symptoms
- each of them : no feel of disease
- MCVS incidence DRAMATICALLY INCREASES in both European and US population last 3 decades
- MCVS substantially increases THE RISK OF CIVILISATION DISEASES after 2 or more decades of its influence, i.e. it contributes to our earlier death compared to theoretical possibility (as result from our genome) in more then 50 % of us
List of known symptoms
A) INSULINREZISTENCE (probably appears as the first sign)
B) DYSLIPEMIA (HDL, LDL, tot. CHOL, TG)
C) OBESITY (BMI > 30 is almost a clear sign of insulin resistance)
E) HYPERTENSION
f) OTHER BIOCHEMICAL SIGNS
- HYPERHOMOCYSTEINEMIA (to prevent eat folic acid)
- HYPERURIKAEMIA
- maybe even increased level of plasmatic iron
- suspect: any impaired antioxidant capacity of blood
additional risk factors for patients with MCVS
* genetic risk (find it by family history)
* smoking , drug abuse
* psychological + social factors
* type A personality, (emotional lability, typ A behavior pattern)
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late symptoms : fully developed diseases as result of MCVS:
(examples of most frequent ones:)
coronary heart disease
stroke
type II diabetes mellitus
any type of ischemic disease due to atherosclerosis
Main benefits of exercise therapy (as a part of non - pharmacologic intervention, together with dietologic, psychologic and social intervention):
A) Possible benefits of exercise therapy for a patient with signs of metabolic syndrome:
+ improved muscular insulin receptors sensitivity
(after 1 hour of intensive exercise above 50 % of heart reserve insulin receptors sensitivity substantially increases and remains high for about 40 - 60 hours)
+ improved lipid profile
(after weeks of training; triglycerides drops after about 2 weeks , total cholesterol drops within 1-2 months, HDL increases within 2 months of intensive training)
+ blood pressure drops (first 10 mm Hg within weeks, next 10 mmHg after weight reduction) - more in patients with developed metabolic syndrome compared to simple essential hypertension without obesity, insulinresistence and dyslipemia.
+ weight reduction (if the caloric intake remains identical and energy expenditure increases)
B) Exercise therapy: other benefits for majority of patients
* Better stress tolerance
* Offset the deleterious psychological and physiological effects of developed disease in patients with substantial exercise limitation
* Provide additional medical surveillance of patients
* Identify patients with significant cardiovascular, physical, or cognitive impairments that may influence safety
* Enables patients to return to activities of daily living within the limits imposed by their disease (i.e. temporary detraining is canceled)
* Prepare the patients and the support system at home to optimize the recovery following hospital discharge
* Elevated patient's self - esteem
* Improved functional ability
* Decrease anxiety and depression from disease
* Increased probability of a healthier life style (smoking cessation, weight reduction long lasting changes in diet)
CARDIAC REHABILITATION
Exercise programs for cardiac patients are traditionally categorized as Phase I (inpatient), Phase II (outpatient - up to 12 weeks of continuous ECG telemetry following discharge), Phase III (outpatient - variable length program of intermittent or no EKG monitoring under supervision) and Phase IV (outpatient - no ECG monitoring, limited supervision).
Clinical indications for cardiac rehabilitation
1. Two or more symptoms of metabolic syndrome
(in fact, majority of diseases listed below are results of developed metabolic syndrome...)
2. Stable angina
3. Coronary artery bypass graft (CABG) surgery
4. Percutaneus transluminal coronary angioplasty (PTCA)
5. Medically stable post-MI
6. Cardiomyopathy
7. Hearth or other organ transplantation
8. Other cardiac surgery including valvular and pacemaker insertion
9. Peripheral vascular disease
10. High-risk cardiovascular disease ineligible for surgical intervention
11. Compensated congestive hearth failure hyperlipidemia, hypertension, etc.
12. Any other patient who may benefit from structured exercise and/or patient education (based on physician referral and consensus of the rehabilitation team)