What parameters are measured during exercise test?
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TIME

The time represents time interval in seconds or minutes (etc.) during it the examined person worked under certain constraint or increasing intensity of load or that was needed to reach certain physical performance.

LOAD

The load (performance) is defined in ergometry with the help of the load source that allows expressing its volume in Watts. It is also expressed in conversion on one kilogram of the body mass (W/kg). For the load dosing and the result interpretation it is necessary to respect age, sex, weigh and in cases of patient also the type and the degree of disease seriousness.

HEART RATE

The heart rate HR (beats/minute) is one of the main cardiovascular functional indicators. In cases healthy persons it rises with increasing physical stress linearly up to the submaximal intensity, at level approximately 75 - 85 per-cent of maximum there is the gentle declaration of increase up to the level of maximal heart rate HRmax. At this level the examined person can (according to efficiency and motivation) remain for other few minutes. The rise of HR is usually accompanied by increased oxygen uptake and cardiac output. Given relations however do not apply to most persons with cardiovascular or some other inner diseases. This fact, together with regard to some other inner or outside factors influencing value HR, e.g. low sensitivity, specification and validating of the indicator, we must have on mind when interpreting indicator reaction. The most suitable is ECG reading or cardiotachometer, for field conditions telemetry or Holter system. It can be use also the Heart rate monitors supplied with watches, measuring with the help of body strip.

RESPIRATORY MINUTE VOLUME

The respiratory minute volume of inspired air VI or more often used VE for exhaled air is expressed in liter/min. VE depends on respiratory rate (8-14 /min.) and tidal volume (400 - 600 ml). The measured results are corrected according to the temperature of surroundings and barometric air pressure by multiplying will factor BTPS. In cases of persons with the disorder of cardiovascular functions where there are found out qualitative and quantitative differences in reactions in compare with healthy persons, this value is one of the most limiting factors of the capacity of the whole transport system.

OXYGEN UTILIZATION

The oxygen utilization O2 (Concentration of inspired O2 - Concentration of expired O2 ).
(FIO2-FE02)
It is expressed in per cents informs of functional ability for respiratory exchange of gases. It is usually not interpreted independently and mostly it is used for the calculation of oxygen uptake. Efficient persons are able to utilize 5-7 % of oxygen during physical stress, ordinary trained persons 3-4% and those with disorder of cardiovascular functions substantially less.

OXYGEN UPTAKE

The oxygen uptake (VO2) is the amount of oxygen delivered to tissues in a unit of time (1 minute). It is an aerometabolic abilities indicator of organism and a transport system efficiency. It complies with basic criteria of exercise tests; objectivity, reproducibility and validity. Its describing abilities are restricted because it does not allow specifically diagnose changes of individual organs and functions. In cases of lower load of the same level it increases exponentially for 1 to 3 minutes proportionately to intensity up to level of steady state. In case of gradually increased dynamic work it grows linearly up to the submaximum. The next increase to the maximum is more gentle where it remains temporary at the same level and is not increased any more (leveling off) although the intensity of load is further increased. This response is one of the main criterions for the reacting of aerometabolic maximum, this applies first of all to healthy and efficient person. VO 2 is expressed in milliliters/min. or litters/min. re-counted with the factor STPD on standard conditions. In the practice for the load dosing and result interpretation are very often used the values of formula considering interindividual differences in bodyweight. The determination of VO 2 is based on the calculation:

VO2 = VE*(FIO2-FE02)

The restriction of aerometabolic abilities is particularly important for considering of transport system disorder seriousness first of all cardiovascular diseases.

PRODUCTION OF THE CARBON DIOXIDE

The production of the carbon dioxide ( VCO2 ) is used as complementary value in routine exercise medicine first of all for non-invasive measurement of anaerobic threshold and for the determination of value R; RQ respectively.

RESPIRATORY EXCHANGE RATIO

The respiratory exchange ratio R has its importance as a criterion for reaching maximal metabolic level (> 1), a piece of information about metabolic proportion of energetic substrates, a decisive factor for non-invasive determination of anaerobic threshold.

R = VCO2 /VO2

This proportion is sometimes wrongly identified as a respiratory quotient (RQ). RQ which is not identical with R during high intensity of work. R = RQ applies only for load in steady state and for gas exchange at cellular level.

RESPIRATION EQUIVALENT

The respiration equivalent REO2 is an amount of air in litters that passed through the lungs and from which an organism takes 1 liter of oxygen. In position at rest it is 20-30 liters. At low intensity load it firstly slowly decreases and with the next increase of load it rises gently, later steeply. The course has got exponential character and the spot of inflexion (the beginning of sheer increase) corresponds with the level of anaerobic threshold. The values REO2 are an indicator of breathing economy. Efficient and healthy persons have at the same load lower results, less efficient proves a reduced economy of gas exchange corresponding with the capability of oxygen utilization. REO2 is determined by calculation:

REO2 = VE(1 BTPS)/VO2(1 STPD)

The respiration equivalent of carbon dioxide RECO2 is used sometime as the complementary parameter. RECO2 is defined analogically like REO2 (the production of carbon dioxide substitutes the oxygen uptake).

Two correction factors are used. BTPS (Body Temperature Pressure Saturated) means gas volume in human body condition: human body temperature, immediate atmospheric pressure and when saturated with water vapors. This way is usually expressed lungs and volumes capacities correction of volume measured in room temperature and possibly dry condition are transferred on BTPS values with help of tables. STPD (Standard Temperature Pressure Dry) means the volume of gas in standard conditions, temperature 0 C, pressure 101.32 kPa, in dry state. The consumption of oxygen or the outlay of oxide dioxide is expressed in STPD conditions.

PULSE OXYGEN

The pulse oxygen (PULSEO2) is an amount of oxygen in milliliters that is given to tissue by one pulse. It is one of the indicators of efficiency and work economy (the higher is the better) of transport system.

MASS OXYGEN

The mass oxygen (MASSO2) is an amount of oxygen in milliliters that is given to one kilogram of body mass. It should be noted that MASSO2 , is much important than the absolute VO 2 when subjects are evaluated for sports involving elevation of their center of gravity during the movement. In fact, in this case, the bodyweight becomes a limiting factor and must be considered when evaluating aerobic power.

Reference:

[1] Kvaca, P.: Evaluation of spiroergometric parameters for the exercise medicne. CTU Prague: Prague, 1996
 
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