References 1
1. Maestu LP. Reference values in adults. In Ward SA, Palange P, eds. Clinical Exercise Testing. Eur Respir Mon 2007 40 165-185. 2. Whipp BJ, Davis JA, Torres F, Wasserman K. A test to determine the parameters of aerobic function during exercise. J AppZ Physiol 1981 50 217-221. 3. Porszasz J, Stringer W, Casaburi R. Equipment, measurements and quality control in clinical exercise testing. In Ward SA, Palange P, eds. Clinical Exercise Testing. Eur Respir Mon 2007 40 108-128. 4. Gosselink R,...
Carbon dioxide output
Pulmonary Vco2 also has important implications for the integrated systemic response to exercise. For example, taken with Vo2 in the steady state, VCo provides important information regarding the substrate mixture undergoing catabolism. In addition, in the context of arterial blood-gas and acid-base homeostasis, VCo provides an important frame of reference for establishing the normality of the ventilatory response to exercise. Also, Vco2 is an essential determining factor for noninvasive 0L...
Ventilation and acidbase regulation during exercise
Although Pa,cO2 appears to be a regulated variable during moderate exercise in normal subjects, it must be reduced to provide the respiratory compensation that constrains the fall of pH at levels of exercise which induce metabolic acidosis with a consequently reduced arterial HCO3- . This compensatory decrease in Pa,cO2 is a result of carbon dioxide being washed-out of the body stores providing an additional source of expired carbon dioxide at high WRs. However, the standard...
VO2WR relationship
There are several quantifiable features of the VO2 response to incremental exercise that provide important clues to ascertaining why a subject may manifest exercise intolerance. The most obvious of these is the maximum Vo2 most usually inferred from VO2,peak , but additional submaximal indices may also be informative. Interpreting abnormalities in the Vo2 response to incremental exercise requires consideration of its determining variables, as characterised by the Fick Principle. For the body as...
References Utu
1. Ries AL. The role of exercise testing in pulmonary diagnosis. Clin Chest Med 1987 8 81-89. 2. Physiology of exercise. In Wasserman K, Hansen JE, Sue DY, Whipp BJ, Stringer WW, eds. Principles of Exercise Testing and Interpretation Including Pathophysiology and Clinical Applications. 4th Edn. Philadelphia, Lippincott Williams amp Wilkins, 2005 pp. 10-65. 3. Wasserman K, Whipp BJ. Exercise physiology in health and disease. Am Rev Respir Dis 1975 112 219-249. 4. Whipp BJ. The physiological and...
Comparison of selfpaced and externally paced shuttle walking tests
Although the self- and externally paced SWTs are fundamentally different, attempts have been made to compare the two protocols. The original study describing the SWT included a comparison with the 6MWT 6 . The authors found that the distance completed in both tests was similar for the majority of patients, but that the pattern of response was different. More recently, Eiser et al. 73 compared the reliability, reproducibility and sensitivity to change of the 6MWT, 2MWT and ISWT in 57...
Endtidal PO2 and PCO2
The alveolar gas values determined at the end of an exhalation the end-tidal values are easy to measure but extremely difficult to interpret. During exhalation, PA,co2 continues to increase fig. 9 at a rate that is dependent on the mixed venous Pco2 Pn,co2 value and to a level that depends on the duration of the exhalation tE . Pet,co2 may, therefore, be considered to be the peak of the intra-breath oscillation of PA,co2 and Pa,co2 during the breathing cycle whereas the measured Pa,co2, usually...
Efficiency of muscle contraction
The overall muscular efficiency gm is reflected by the product of the two efficiencies where gp and gc are the efficiencies of phosphorylative coupling and contraction coupling, respectively. However, the contracting muscles must be effectively orchestrated to perform the task i.e. a manifestation of the skill gs with which the task is accomplished. Unskilled performance of the task involving, for example, extraneous movements will naturally reduce the overall efficiency of accomplishing the...
References Nol
1. Gandevia B, Hugh-Jones P. Terminology of measurements of ventilatory capacity. Thorax 1957 12 290-293. 2. Dillard TA, Piantadosi S, Rajagopal KR. Prediction of ventilation at maximal exercise in chronic airflow obstruction. Am Rev Respir Dis 1985 132 230-235. 3. Johnson BD, Weisman IM, Zeballos RJ, Beck KC. Emerging concepts in the evaluation of ventilatory limitation during exercise the exercise tidal flow-volume loop. Chest 1999 116 488-503. 4. Killian KJ, Leblanc P, Martin DH, Summers E,...
Patterns of response diagnostic for cardiac disease
Centro Cardiologico Monzino, IRCCS, Institute of Cardiology, University of Milan, Milan, Italy. Division of Respiratory and Critical Care Medicine, Dept of Medicine, University of Washington, Seattle, WA, USA. Correspondence P. Agostoni, Centro Cardiologico Monzino, IRCCS, Institute of Cardiology, University of Milan, via Parea 4, 20138 Milan, Italy. Fax 39 258011039 E-mail piergiuseppe.agostoni CCFM.it
ATP the direct energy source for muscle contraction
While ATP is the obligatory energy resource for muscle contraction, its concentration in skeletal muscle is extremely small 5 mM-kg-1 sufficient in itself to sustain a high-intensity activity for only a few seconds. Despite this, its concentration does not decrease during dynamic exercise e.g. 6, 7 , except at extremely high work-rates WRs e.g. 8 , and not always then e.g. 6 . This is because the production rate of ATP is increased through the intensity-dependent contributions from aerobic and...
Limiting factors
On the basis of the contracting muscles apparently having a greater potential to accommodate blood flow than is actually achieved at maximum exercise, the output of the heart is considered to provide the more important cardiovascular limitation to exercise involving large muscle mass in normal subjects e.g. 90, 92, 106, 107 . However, even in trained athletes during maximal exercise at very high rates of oxygen utilisation, not all oxygen offered to muscles can be extracted. Interestingly, when...
Oxygen pulse
Further inferences for cardiovascular function may be drawn from a slight modification of the Fick relationship The variable V'o2fC, termed the oxygen pulse'' O2-P , was defined, by Henderson and Prince 99 as the amount of oxygen consumed by the body from the blood of one systolic discharge of the heart''. It is, therefore, determined by the product of SV and Ca,O2-Cv,O2. Consequently, if one is prepared to make the assumption that one or the other variable is constant, then the change in O2-P...