Failure of prolonged exercise training to increase red cell mass in
humans.
Shoemaker, J. K., H. J. Green, J. Coates, M. Ali, and S. Grant.
Department of Kinesiology, University of Waterloo, Waterloo, ON,
N2L 3G1, Faculty of Health Sciences, McMaster University Medical
Centre, Hamilton, ON, L8N 2Z5, Department of Hematology, St. Joseph's
Hospital, Hamilton, ON, L8N 4A6
APStracts 2:0297H, 1995.
The purpose of this study was to investigate the time-dependent
effects of long-term, prolonged exercise training on vascular volumes
and hematological status. Training using 7 untrained males (age
21.1+/-1.4 yr, X+/-SE) initially consisted of cycling at 68% of peak
aerobic power (O2peak) for 2h/day, 4-5 days/wk for 11 wks. Absolute
training intensity was increased every 3 wks. Red cell mass (RCM),
obtained using 51Cr, was unchanged (P>0.05) with training
(2142+/-95, 2168+/-86, 2003+/-112 and 2080+/-116 ml at 0, 3, 6 and 11
wks, respectively) as were serum erythropoietin levels (17.1+/-4.3,
13.9+/-3.5 and 17.0+/-2.0 U/l at 0, 6 and 11 wks, respectively).
Plasma volume (PV) measured with 125I labelled albumin and total
blood volume (TBV) were also not significantly altered. The increase
in mean cell volume (MCV) that occurred with training (89.7+/-0.95 vs
91.0+/-1.0 fl, 0 vs 6 wks, P<0.05) was not accompanied by
changes in either mean cell hemoglobin (MCH) or mean cell hemoglobin
concentration (MCHC). Serum ferritin was reduced 73% with training
(67.4+/-13 to 17.9+/-1 Ng/l, 0 vs 11 wks, P<0.05). Total
hemoglobin (HbTOT) calculated as the product of hemoglobin
concentration and TBV was unaltered (P>0.05) at both 6 and 11
wks of training. The 15% increase in O2peak (3.39+/-0.16 to 3.87+/
-0.14 l/min, 0 vs 11 wks, P<0.05) with training occurred despite
a failure of training to change TBV, RCM or HbTOT.
Received 23 March 1995; accepted in final form 7 July 1995.
APS Manuscript Number H283-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 18 July 1995.