Mineral metabolism in male cyclists during high-intensity endurance training.
This study examined the effects of intense endurance training on basal plasma and 24-hour urinary calcium (Ca), magnesium (Mg), iron (Fe), zinc (Zn), and copper (Cu) levels in 9 male competitive cyclists. The supervised training program followed a baseline period and included a volume phase (6 weeks, averaging 87% of maximal heart rate [HR(max)]), an interval phase (18 days, 100% of HR(max)), and a 10-day unloading taper. The primary training outcome measure was 20-km time-trial cycling performance. Subjects ate unrestricted diets and maintained their weight. Compared to baseline, performance improved significantly (p < .05), while mineral metabolism was not significantly different after the volume phase. However, after the interval phase, renal Ca excretion increased (p < .05) and plasma Ca fell slightly below the clinical norm. As compared to the interval phase, urinary Ca decreased (p <.05), plasma Ca increased (p < .05), and performance further improved (p < .05) after the taper. Whereas Mg, Fe, Zn, and Cu metabolism remained unchanged throughout the study, greater renal Ca excretion was associated with very high intensity interval training.
Dressendorfer
Rudolph H
RH
Faculty of Physical Education and Recreation at the University of Alberta, Edmonton, Canada.
Petersen
Stewart R
SR
Lovshin
Shona E Moss
SE
Keen
Carl L
CL
D000328:Adult; D001642:Bicycling / Q000502:physiology*; D002118:Calcium / Q000097:blood / Q000378:metabolism* / Q000652:urine; D003300:Copper / Q000097:blood / Q000378:metabolism / Q000652:urine; D006801:Humans; D007501:Iron / Q000097:blood / Q000378:metabolism / Q000652:urine; D007668:Kidney / Q000378:metabolism*; D008274:Magnesium / Q000097:blood / Q000378:metabolism / Q000652:urine; D008297:Male; D008903:Minerals / Q000097:blood / Q000378:metabolism* / Q000652:urine; D010809:Physical Fitness / Q000502:physiology*; D015032:Zinc / Q000097:blood / Q000378:metabolism / Q000652:urine
D008903:Minerals; D003300:Copper; D007501:Iron; D008274:Magnesium; D015032:Zinc; D002118:Calcium