Oxygen consumption and work capacity in iron-deficient anemic rats
Ohira, Y.; Koziol, B.J.; Edgerton, V.R.; Brooks, G.A.
Journal of Nutrition 111(1): 17-25
1981
ISSN/ISBN: 0022-3166 PMID: 7452368 Document Number: 169371
The effects of moderate and severe chronic Fe deficiency anemia on O2 consumption (.ovrhdot.VO2) and heart rate were determined during submaximal and maximal exercise. In adult male rats, moderate (MA) and severe anemia (SA) was induced by repeated phlebotomy and Fe-deficient diet and Hb levels were maintained at .apprx. 8 and 4 g/dl for 360 and 210 days, respectively. Plasma Fe levels for both MA (130 .+-. 17 .mu.g/dl) and SA rats (42 .+-. 19) were lower than their respective sham controls (184 .+-. 19 and 215 .+-. 22). The final mean Hb values of these same groups were 7.9 .+-. 0.2, 3.7 .+-. 0.2, 13.5 .+-. 0.2 and 13.3 .+-. 0.5 g/dl, respectively. Maximal .ovrhdot.VO2 in both MA (45.9 .+-. 1.7 ml/kg per min) and SA (29.8 .+-. 2.4) groups was lower than in their respective control groups (54.5 .+-. 2.5 and 56.0 .+-. 2.8). Run time to exhaustion for these same groups was 5.0 .+-. 0.3, 2.8 .+-. 0.3, 6.6 .+-. 0.2 and 7.3 .+-. 0.5 min, respectively. Run time to exhaustion correlated with maximal .ovrhdot.VO2 (r = 0.77) and Hb (r = 0.85). Maximal .ovrhdot.VO2 and Hb concentration were significantly correlated (r = 0.81). The lower maximal .ovrhdot.VO2 and physical work capacities in the MA and SA rats were due primarily to reduced Hb levels. The submaximal .ovrhdot.VO2 at the same work load was higher in rats with higher plasma Fe than in rats with lower plasma Fe although their Hb levels were the same. The degree of reduction of .ovrhdot.VO2 associated with plasma Fe levels was directly related to the severity of anemia. The severity of anemia apparently does not solely account for the reduction in work performance. The degree of Fe deficiency may also be important.