Commonly used reference values underestimate oxygen uptake in healthy, 50-year-old Swedish women.
Cardiopulmonary exercise testing (CPET) is the gold standard among clinical exercise tests. It combines a conventional stress test with measurement of oxygen uptake (VO2) and CO2production. No validated Swedish reference values exist, and reference values in women are generally understudied. Moreover, the importance of achieved respiratory exchange ratio (RER) and the significance of breathing reserve (BR) at peak exercise in healthy individuals are poorly understood. We compared VO2at maximal load (peakVO2) and anaerobic threshold (VO2@AT) in healthy Swedish individuals with commonly used reference values, taking gender into account. Further, we analysed maximal workload and peakVO2with regard to peak RER and BR. In all, 181 healthy, 50-year-old individuals (91 women) performed CPET. PeakVO2was best predicted using Jones et al. (100·5%), while SHIP reference values underestimated peakVO2most: 112·5%. Furthermore, underestimation of peakVO2in women was found for all studied reference values (P<0·001) and was largest for SHIP: women had 128% of predicted peakVO2, while men had 104%. PeakVO2was similar in subjects with peak RER of 1-1·1 and RER > 1·1 (2 328·7 versus 2 176·7 ml min-1, P = 0·11). Lower BR (≤30%) related to significantly higher peakVO2(P<0·001). In conclusion, peakVO2was best predicted by Jones. All studied reference values underestimated oxygen uptake in women. No evidence for demanding RER > 1·1 in healthy individuals was found. A lowered BR is probably a normal response to higher workloads in healthy individuals.
Department of Medical Sciences, Clinical Physiology, Uppsala University, Uppsala, Sweden.|Centre for Research & Development, Uppsala University, Region Gävleborg, Sweden.
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Genberg
Department of Medical Sciences, Clinical Physiology, Uppsala University, Uppsala, Sweden.
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Andrén
Department of Medical Sciences, Cardiovascular Epidemiology, Uppsala University, Uppsala, Sweden.
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Lind
Department of Medical Sciences, Clinical Physiology, Uppsala University, Uppsala, Sweden.
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Hedenström
Department of Medical Sciences, Clinical Physiology, Uppsala University, Uppsala, Sweden.
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Malinovschi
D000367:Age Factors; D000072599:Cardiorespiratory Fitness; D005080:Exercise Test / Q000592:standards*; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008168:Lung / Q000502:physiology; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000378:metabolism*; D010101:Oxygen Consumption; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012016:Reference Values; D015203:Reproducibility of Results; D012119:Respiration; D012737:Sex Factors; D013147:Spirometry; D013548:Sweden; D014797:Vital Capacity
breathing reserve; cardiopulmonary exercise testing; gender; healthy adults; peak oxygen uptake; reference values; respiratory exchange ratio; work capacity