Abstract
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 [HRmax]), an interval phase (18 days, 100% of HRmax), 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.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 63-72 |
| Number of pages | 10 |
| Journal | International Journal of Sport Nutrition |
| Volume | 12 |
| Issue number | 1 |
| State | Published - 2002 |
| Externally published | Yes |
Keywords
- Athletes
- Endurance sports
- Exercise
- Nutrition
ASJC Scopus subject areas
- Medicine (miscellaneous)
- Endocrinology
- Public Health, Environmental and Occupational Health
- Food Science