Journal of Applied Physiology, Vol 63, Issue 5 1846-1852, Copyright © 1987 by American Physiological Society
Effects of prolonged exercise in highly trained traumatic paraplegic men
G. C. Gass and E. M. Camp
Department of Biological Sciences, Cumberland College of Health Sciences, Sydney, Australia.
This study investigated the cardiovascular and metabolic responses to
prolonged wheelchair exercise in a group of highly trained, traumatic
paraplegic men. Six endurance-trained subjects with spinal cord lesions
from T10 to T12/L3 underwent a maximal incremental exercise test in which
they propelled their own track wheelchairs on a motor-driven treadmill to
exhaustion to determine maximal O2 uptake (VO2max) and related variables.
One week later each subject exercised in the same wheelchair on a motorized
treadmill at 60-65% of VO2max for 80 min in a thermoneutral environment
(dry bulb 22 degrees C, wet bulb 17 degrees C). Approximately 10 ml of
venous blood were withdrawn both 20 min and immediately before exercise (0
min), after 40 and 80 min of exercise, and 20 min postexercise. Venous
blood was analyzed for hematocrit (Hct), hemoglobin (Hb), and lactate, and
the separated plasma was analyzed for glucose, K+, Na+, Cl-, free fatty
acid (FFA), and osmolality. VO2, CO2 production (VCO2), minute ventilation
(VE), respiratory exchange ratio (R), net efficiency, and wheelchair strike
rate were determined at four intervals throughout the exercise period. Data
were analyzed with an analysis of variance repeated-measures design and a
Scheffe post hoc test. VO2max was 47.5 +/- 1.8 (SE) ml.min-1.kg-1 with
maximal VE BTPS and maximal heart rate (HR) being 100.1 +/- 3.8 l/min and
190 +/- 1 beats/min, respectively. During prolonged exercise there were no
significant changes in VO2, VCO2, VE, R, net efficiency, wheelchair strike
rate, and lactate, glucose, and Na+ concentrations. Significant increases
occurred in HR, FFA, K+, Cl-, osmolality, Hb, and Hct throughout
exercise.(ABSTRACT TRUNCATED AT 250 WORDS)
