Cardiovascular and hemodynamic responses on dryland vs. immersed cycling.
OBJECTIVES
To investigate the effect of water immersion on oxygen uptake (VO2) and central hemodynamic responses during incremental maximal exercise at the same external power output (P ext) and recovery on an immersible ergocycle vs. a dryland ergocycle.


DESIGN
Cross-over design study.


METHODS
Twenty healthy participants (32 ± 7 years; 173 ± 6 cm; 71.7 ± 9.7 kg) performed maximal incremental exercise tests while pedalling either immersed on immersible ergocycle (Hydrorider(®)) or on dryland ergocycle (Ergoline 800 S; Bitz, Germany). Initial P ext of dryland ergocycle protocol was set at 25 W and increased by 25 W every minute until exhaustion. P ext on immersible ergocycle was controlled by pedalling rate (rpm). Initial rpm was set at 40 rpm and was increased by 10 rpm until 70 rpm and thereafter by 5 rpm until exhaustion. Gas exchange and central hemodynamic parameters were measured continuously during exercise and a 5-min recovery period. Reported VO2, stroke volume, cardiac output (Q) and arteriovenous difference (C(a-v)O2) were compared.


RESULTS
During exercise on immersible ergocycle, VO2 and C(a-v)O2 were lower (P < 0.0001) whereas stroke volume and Q were higher (P < 0.05) relative to a dryland ergocycle exercise of equivalent P ext.


CONCLUSIONS
During exercise and recovery in immersion, (VO2) and arteriovenous difference were reduced in healthy young participants, while stroke volume and cardiac output were increased for the same P ext. During the recovery, central hemodynamics responses remained higher in immersible ergocycle.
['Garzon|Mauricio|M|', 'Juneau|Martin|M|', 'Dupuy|Olivier|O|', 'Nigam|Anil|A|', 'Bosquet|Laurent|L|', 'Comtois|Alain|A|', 'Gayda|Mathieu|M|']
D000328:Adult D001642:Bicycling D002302:Cardiac Output D018592:Cross-Over Studies D005080:Exercise Test D005260:Female D064368:Healthy Volunteers D006801:Humans D007101:Immersion D008297:Male D010101:Oxygen Consumption D011897:Random Allocation D013318:Stroke Volume
Oxygen uptake Central hemodynamic External power output Immersed ergocycle Pedalling rate