Physiology of oxygen uptake kinetics: Insights from incremental cardiopulmonary exercise testing in the Study of Health in Pomerania.
BACKGROUND
Cardiopulmonary exercise testing allows for assessment of cardiac and respiratory limitation, but is often affected by patient effort. Indices of oxygen kinetics, including the oxygen uptake efficiency slope (OUES), oxygen uptake-work-rate slope (VO2-WR slope) and the heart rate-oxygen uptake slope (HR-VO2slope) are relatively effort independent but may be affected by patient characteristics. The objective of this study is to identify the impact of factors, such as age, gender, body size, respiratory function, smoking and beta-blockade on these parameters, as well as generate predictive equations.


METHODS
1708 volunteers from the population-based Study of Health in Pomerania underwent an incremental bicycle exercise protocol. Markers of oxygen kinetics were calculated. Participants with structural heart disease, echocardiographic or lung function pathology were excluded, leaving 577 males and 625 females. Age, height, weight, smoking, forced expiratory volume in 1 s (FEV1) and beta-blockers were analysed for their influencing power by gender. Quantile regression analysis determined the reference equations for each parameter.


RESULTS
Age, gender, height, weight and FEV1(but not percent predicted FEV1) are strongly related to OUES. Participants using beta-blockers and male smokers had significantly lower OUES values. VO2-WR slope was minimally affected by age, gender, weight and FEV1. Gender, height, weight and beta-blocker use, but not FEV1and smoking status, were related to the HR-VO2slope whilst age was only related in females.


CONCLUSIONS
Markers of oxygen kinetics are differentially affected by patient characteristics. This study provides normal reference values for these variables thereby facilitating interpretation of oxygen uptake kinetics in health and disease.
International Centre for Circulatory Health, Imperial College London and Imperial College NHS Trust, UK.
Anthony J
AJ
Barron
International Centre for Circulatory Health, Imperial College London and Imperial College NHS Trust, UK.
Niti M
NM
Dhutia
Department of Internal Medicine B-Cardiology, Intensive Care, Pulmonary Medicine and Infectious Diseases, University of Greifswald, Greifswald, Germany.
Sven
S
Gläser
Department of Internal Medicine B-Cardiology, Intensive Care, Pulmonary Medicine and Infectious Diseases, University of Greifswald, Greifswald, Germany.
Beate
B
Koch
Department of Internal Medicine B-Cardiology, Intensive Care, Pulmonary Medicine and Infectious Diseases, University of Greifswald, Greifswald, Germany.
Ralf
R
Ewert
Department of Internal Medicine B-Cardiology, Intensive Care, Pulmonary Medicine and Infectious Diseases, University of Greifswald, Greifswald, Germany.
Anne
A
Obst
Department of Internal Medicine B-Cardiology, Intensive Care, Pulmonary Medicine and Infectious Diseases, University of Greifswald, Greifswald, Germany ; DZHK (German Centre for Cardiovascular Research), partner site Greifswald, Greifswald, Germany.
Marcus
M
Dörr
DZHK (German Centre for Cardiovascular Research), partner site Greifswald, Greifswald, Germany ; Institute for Community Medicine, SHIP/Clinical-Epidemiological Research, University of Greifswald, Greifswald, Germany.
Henry
H
Völzke
International Centre for Circulatory Health, Imperial College London and Imperial College NHS Trust, UK.
Darrel P
DP
Francis
International Centre for Circulatory Health, Imperial College London and Imperial College NHS Trust, UK ; Watford General Hospital, West Herts NHS Trust, UK.
Roland
R
Wensel
Cardiopulmonary exercise testing; Oxygen uptake efficiency slope; Reference values; Study of Health in Pomerania