Effects of successive running and cycling on the release of atrial natriuretic factor in highly trained triathletes.
OBJECTIVE
To evaluate the influence of successive running and cycling on both exercise-induced arterial hypoxemia (EIAH) and atrial natriuretic factor (ANF) release, 5 triathletes performed 2 separate exercise trials.


METHODS
One trial consisted of a 20-min+20-min successive cycle-run exercise (C(1)-R(2)) and the other consisted of a 20-min+20-min successive run-cycle exercise (R(1)-C(2)). Arterial oxygenation (PaO(2)) and ANF were determined at pre-exercise, at the end of each 20-min segment of exercise and after 10 min of recovery.


RESULTS
EIAH was noted during C(1)-R(2) and R(1)-C(2) trials. A higher EIAH was observed during running compared with cycling performed in the 1(st) position (R(1) vs C(1)) in the succession. In contrast, no difference was observed between successive running and successive cycling (R(2) vs C(2)), (-10.6+/-7.0 vs -15.6+/-4.0 mmHg for C(1)-R(2) and -20.9+/-6.0 vs -16.2+/-2.4 mmHg for R(1)-C(2)). ANF showed no difference between cycling and running performed in first position, whereas a significantly lower ANF was observed during successive cycling compared with successive running (C(2) vs R(2)) (19.9+/-3.72 vs 36.2+/-6.4 pmol.L(-1)). During recovery, neither PaO(2) nor ANF plasma returned to baseline level after either trial.


CONCLUSIONS
This study provides new information on some of the physiological modifications that occur during multi-sports. Specifically, the impact of the modality of the successive exercise on ANF release and body fluid regulation was observed. Cycling as the successive exercise seems to cause lower ANF release than does running.
Galy
O
O
ACTES Laboratory, Unit of Technical Sciences Training and Research, Physical and Sports Achivities of Antille-Guyana, Point a Pitre, France. galy.o@wanadoo.fr
Hue
O
O
Peyreigne
C
C
Boussana
A
A
Chamari
K
K
Libicz
S
S
Couret
I
I
Le Gallais
D
D
Préfaut
C
C
D000222:Adaptation, Physiological; D000328:Adult; D009320:Atrial Natriuretic Factor / Q000097:blood* / Q000378:metabolism / Q000502:physiology; D001642:Bicycling / Q000502:physiology*; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D010807:Physical Endurance / Q000502:physiology; D012420:Running / Q000502:physiology*; D013318:Stroke Volume / Q000502:physiology
D009320:Atrial Natriuretic Factor