Muscular Oxygen Uptake Kinetics in Aged Adults.
Pulmonary oxygen uptake (V˙O2) kinetics and heart rate kinetics are influenced by age and fitness. Muscular V˙O2 kinetics can be estimated from heart rate and pulmonary V˙O2. In this study the applicability of a test using pseudo-random binary sequences in combination with a model to estimate muscular V˙O2 kinetics was tested. Muscular V˙O2 kinetics were expected to be faster than pulmonary V˙O2 kinetics, slowed in aged subjects and correlated with maximum V˙O2 and heart rate kinetics. 27 elderly subjects (73±3 years; 81.1±8.2 kg; 175±4.7 cm) participated. Cardiorespiratory kinetics were assessed using the maximum of cross-correlation functions, higher maxima implying faster kinetics. Muscular V˙O2 kinetics were faster than pulmonary V˙O2 kinetics (0.31±0.1 vs. 0.29±0.1 s; p=0.004). Heart rate kinetics were not correlated with muscular or pulmonary V˙O2 kinetics or maximum V˙O2. Muscular V˙O2 kinetics correlated with maximum V˙O2 (r=0.35; p=0.033). This suggests, that muscular V˙O2 kinetics are faster than estimates from pulmonary V˙O2 and related to maximum V˙O2 in aged subjects. In the future this experimental approach may help to characterize alterations in muscular V˙O2 under various conditions independent of motivation and maximal effort.
Institute of Physiology and Anatomy, German Sport University Cologne, Cologne, Germany.
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J
Koschate
Institute of Physiology and Anatomy, German Sport University Cologne, Cologne, Germany.
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U
Drescher
Institute of Physiology and Anatomy, German Sport University Cologne, Cologne, Germany.
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K
Baum
Institute of Sport Gerontology, Cologne, German Sport University Cologne, Cologne, Germany.
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S
Eichberg
Outpatient Clinic for Sports Traumatology and Public Health Consultation, German Sport University Cologne, Cologne, Germany.
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T
Schiffer
Institute of Cardiovascular Research and Sports Medicine, Department of Preventive and Rehabilitative Sport Medicine, German Sport University Cologne, Cologne, Germany.
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J
Latsch
Institute of Cardiovascular Research and Sport Medicine, Department of Molecular and Cellular Sport Medicine, Cologne, Germany.
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K
Brixius
Institute of Physiology and Anatomy, German Sport University Cologne, Cologne, Germany.
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U
Hoffmann
D000368:Aged; D000072599:Cardiorespiratory Fitness; D005080:Exercise Test; D006339:Heart Rate; D006801:Humans; D007700:Kinetics; D008168:Lung / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology*