The effect of iron therapy on the exercise capacity of nonanemic iron-deficient adolescent runners.
Iron-deficiency anemia impairs exercise capacity, but whether nonanemic iron depletion decreases endurance performance is unclear. In 14 iron-deficient (serum ferritin level, less than 20 micrograms/L [less than 20 ng/L])nonanemic runners, hematologic and treadmill running values were followed up during a competitive season. Following a four-week control period, runners were treated for one month in a double-blind protocol with ferrous sulfate (975 mg/d) or placebo. During treatment, the mean ferritin level rose from 8.7 to 26.6 micrograms/L (8.7 to 26.6 ng/mL) in those patients taking iron and fell from 10.6 to 8.6 micrograms/L (10.7 to 8.6 ng/mL) in the placebo group. Treadmill endurance times improved significantly in the iron-treated runners compared with controls. Endurance time declined in all seven controls (range, 0.07 to 1.30 minutes), while six of seven iron-treated subjects improved their performance (range, 0.03 to 1.92 minutes). No significant differences in maximal or submaximal oxygen consumption, ventilation, or heart rate were observed between the groups except for a 4% increase in maximum oxygen consumption during placebo treatment. These data indicate that nonanemic iron deficiency impairs exercise performance but does not influence gas exchange or cardiac measures.
Rowland
T W
TW
Department of Pediatrics, Baystate Medical Center, Springfield, MA 01199.
Deisroth
M B
MB
Green
G M
GM
Kelleher
J F
JF
D000293:Adolescent; D003692:Delayed-Action Preparations; D004311:Double-Blind Method; D005260:Female; D005293:Ferritins / Q000032:analysis; D005296:Ferrous Compounds / Q000627:therapeutic use*; D006339:Heart Rate; D006801:Humans; D000090463:Iron Deficiencies; D010807:Physical Endurance; D005082:Physical Exertion; D011659:Pulmonary Gas Exchange; D012420:Running; D013997:Time Factors
D003692:Delayed-Action Preparations; D005296:Ferrous Compounds; C020748:ferrous sulfate; D005293:Ferritins