Inter‐individual differences in coupling oxygen delivery to exercising muscle metabolic demand

That oxygen delivery (O2del) is “tightly matched” to metabolic demand is widely accepted based on traditional data analysis using group means. Little consideration has been given to the investigation of inter‐individual differences in this coupling.PURPOSETo determine the degree of inter‐individual differences in O2del:metabolic demand coupling in healthy young males.METHODSEleven recreationally active (271.38 ± 6.74 METS) healthy males (24.18 ± 2.08 yrs) performed rhythmic isometric handgrip contractions at a fixed metabolic demand (1 s: 2 s contraction: relaxation duty cycle, 30 kg force) until failure. Forearm O2del was calculated as arterial oxygen content (O2 saturation via pulse oximeter; [hemoglobin] via venous blood sample) x brachial artery blood flow (BABF; Doppler and Echo ultrasound). Data are mean ±SD.RESULTSBABF in last 30 s of exercise: 478 ±150 ml/min, Coefficient of variation (CV) 31%, individual subject values 249, 589, 465, 317, 475, 412, 391, 420, 700, 739, 499 ml/min. O2del last 30 s of exercise: 98 ±30 ml/min, CV 31%, individual subject values 55, 117, 92, 69, 88, 85, 75, 88, 141, 152, 115 ml/min.CONCLUSIONS“Tightness” of O2del:metabolic demand coupling varies substantially between individuals. Investigating inter‐individual variation may provide an important new approach to advancing understanding of integrated cardiovascular response support of exercising muscle. NSERC

Inter‐individual differences in coupling oxygen delivery to exercising muscle metabolic demand Journal Articles