To determine the effect of triathlete performance level on the cardiorespir
atory responses elicited by the cycle-run succession, eight regionally and
nationally-ranked (Competitive) and five internationally-ranked (Elite) mal
e triathletes underwent four successive laboratory trials: 1) an incrementa
l treadmill test, 2) an incremental cycle test, 3) 30 min of cycling follow
ed by 20 min of running (C-R), and 4) a 20-min control run (R) at the same
speed as the run in C-R. Before and 10 min after the third and fourth trial
s the triathletes underwent lung function testing: spirometry and diffusing
capacity testing for carbon monoxide (DLCO). During the C-R trial blood sa
mples were drawn to measure venous lactate concentration. During all trials
ventilatory data were collected every minute using an automated breath-by-
breath system. The results showed that 1) the oxygen uptake ((V)over dot O-
2,) of post-cycling running verses running alone was similar for both group
s; 2) the ventilatory responses ((V)over dot (E) (V)over dot (E)/(V)over do
t O-2,O- (V)over dot (E)/(V)over dot CO2 and f) of C-R running versus R wer
e significantly higher (P < 0.005) for the Competitive group: and 3) a sign
ificant decrease (P < 0.05) in DLCO was also noted after the C-R trial in t
he Competitive group but not in the Elite group. We concluded that 1)the ve
ntilatory responses during a run subsequent to cycling may be related to th
e triathlete performance level, and 2) the C-R trial induced specific alter
ations in pulmonary function that may be associated with respiratory muscle
alteration and exercise-induced hypoxemia in the Competitive triathletes.