Validation of 2 Submaximal Cardiorespiratory Fitness Tests in Patients With Breast Cancer Undergoing Chemotherapy.
Patients with breast cancer have an impaired cardiorespiratory fitness, in part, due to the toxic effects of anticancer therapy. Physical exercise as a means of rehabilitation for patients with cancer is an emerging area of research and treatment, emphasizing the need for accurate and feasible physical capacity measurements. The purpose of this study was to evaluate the validity of peak oxygen consumption (o2peak) predicted by the Ekblom-Bak test (E-B) and the Åstrand-Rhyming prediction model (A-R).


METHODS
Eight patients with breast cancer undergoing chemotherapy participated in the study. Submaximal exercise tests were performed at 2 different submaximal workloads. Estimated o2peakvalues were obtained by inserting the heart rate (HR) from the 2 workloads into the E-B prediction model and the HR of only the higher workload into the Åstrand nomogram. A 20-W incremental cycle test-to-peak effort was performed to obtain o2peakvalues.


RESULTS
Results from A-R overestimated o2peakby 6% (coefficient of variation = 7%), whereas results from E-B overestimated o2peakwith 42% (coefficient of variation = 21%) compared with measured o2peak. Pearson's correlation coefficient revealed a significant strong relationship between the estimated o2peakfrom A-R and the measured o2peak(r= 0.86;P< .05), whereas the relationship between the estimated o2peakfrom E-B and the measured o2peakresulted in a nonsignificant weak correlation (r= 0.21).


CONCLUSIONS
In a situation where maximal exercise testing is not practical or undesirable from a patient safety perspective, submaximal exercise testing provides an alternative way of estimating o2peak. The A-R prediction model appears to be a valid submaximal exercise test for determining cardiorespiratory fitness in this population.
Department of Physiology & Pharmacology, Karolinska Institutet, Stockholm, Sweden.
Sara
S
Mijwel
The Swedish School of Sport and Health Sciences, Stockholm, Sweden; Swedish Sports Confederation, Stockholm, Sweden.
Daniele
D
Cardinale
The Swedish School of Sport and Health Sciences, Stockholm, Sweden.
Elin
E
Ekblom-Bak
Department of Physiology & Pharmacology, Karolinska Institutet, Stockholm, Sweden.
Carl Johan
CJ
Sundberg
Department of Neurobiology Care Science and Society, Division of Nursing, Karolinska Institutet, Stockholm, Sweden.
Yvonne
Y
Wengström
Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.
Helene
H
Rundqvist
Ekblom-Bak test; cancer rehabilitation; heart rate; Åstrand-Rhyming prediction model