Abstract
Strenuous exercise induces proteinuria which is related to the intensity of exercise.
However, renal responses to each type of exercise during a middle-distance triathlon
have not been reported. The present study, carried out on 7 healthy athletes, investigated
renal function at rest and after each exercise of a half-triathlon race. Blood and
urine samples were collected at rest and after each specific event. Protein excretion
and renal clearances were determined on each sample. Compared with resting values,
albuminuria was increased by a factor of 30 (p<0.05) after swimming but did not differ
from the resting value after cycling and running (p>0.05). Rates of β2-microglobulin and retinol-binding protein excretion did not change throughout the
triathlon (p>0.05). Glomerular filtration rate (expressed as creatinine clearance)
remained stable after each exercise event, whereas tubular reabsorption rate (expressed
as urea clearance) was reduced by 50, 40 and 65% after swimming, cycling and running,
respectively, compared to pre-exercise values (p<0.05). Glomerular membrane permeability
(expressed as albumin clearance) was significantly increased by the swimming event
(13 times, p<0.05). These results suggest that middle-distance triathlon has a noticeable
impact on the glomerular membrane permeability (albumin clearance) and elimination
of protein waste (urea clearance) depending on exercise type.
Key words
middle-distance triathlon - proteinuria - kidney filtration - glomerular permeability
- tubular reabsorption
