Volume 45 Number 7, 2008
Pages 1091 — 1102
Abstract - Effects of acute leg ischemia during cycling on oxygen and carbon dioxide stores
Jack A. Loeppky, PhD;1* Burke Gurney, PhD;2 Milton V. Icenogle, MD3
Orthopaedics and Division of Physical Therapy, University of New Mexico Health Sciences Center, Albuquerque, NM; 3Cardiology Section, VAMC, Albuquerque, NM
Abstract — This study estimated changes in whole body oxygen stores (O2s) and carbon dioxide stores (CO2s) during steady state exercise with leg ischemia induced by leg cuff inflation. Six physically fit subjects performed 75 W steady state exercise for 15 min on a cycle ergometer. After 5 min of exercise, cuffs on the upper and lower legs were inflated to 140 mmHg. Cuffs were deflated after 5 min and exercise continued for another 5 min. O2 uptake 
and CO2 output 
significantly increased during the first 30 s after inflation, significantly decreased between 60 and 90 s, and then rose linearly until deflation. and significantly increased further after cuff deflation, peaking between 30 and 60 s and then returned to near baseline exercise levels. Model-estimated changes in total O2s and CO2s were compared with time-integrated store changes from and . During 5 min after cuff deflation, and exceeded the model-estimated change in stores by 273 and 697 mL, respectively. These results reflect the O2 cost repayment of the anaerobic component and lactate buffering to neutralize circulating metabolites caused by the preceding ischemia.
Key words: anaerobic exercise, bicarbonate buffering, carbon dioxide stores, ergoreflex, ischemia, lactate, oxygen deficit, oxygen stores, rehabilitation, ventilation/perfusion ratio, ventilation response.
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