Comparison of Cardiorespiratory and Hormonal Responses between Sustained Constant and Alternating Intensity Exercise
2Cardiopulmonary Exercise Testing and Rehabilitation Laboratory, Evgenidio Hospital, School of Medicine, National & Kapodistrian University of Athens, Greece, 20 Papadiamantopoulou Str., 115 28, Athens, Greece
- *Corresponding Author:
- Dr. Sofia S. Spanoudaki
Department of Sports Medicine & Biology of Physical Activity
Faculty of Physical Education and Sports Science
National & Kapodistrian University of Athens
Valtetsiou St, Vrilissia 15235, Athens, Greece
E-mail: [email protected]
Received Date: September 09, 2011; Accepted Date: January 06, 2012; Published Date: January 10, 2012
Citation: Spanoudaki S, Maridaki M, Karatzanos E, Bogdanis GC, Spanoudaki C, et al. (2012) Comparison of Cardiorespiratory and Hormonal Responses between Sustained Constant and Alternating Intensity Exercise. J Sport Medic Doping Studie 2:103. doi:10.4172/2161-0673.1000103
Copyright: © 2012 Spanoudaki S, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Background: Cardiorespiratory and hormonal responses were investigated during and after prolonged exercise of constant and alternating exercise intensity. Methods: Ten healthy males underwent two main cycling exercise trials at the same overall power output, lasting one hour each. During the first trial, exercise intensity was constant at 70±5% VO2max, while during the second trial, exercise intensity was alternated between 47±2% VO2max for 40 s and 120% VO2max for 20 s. Results: Oxygen uptake (VO2) and heart rate (HR) were higher in constant compared with alternating intensity exercise (VO2: 32.5±6.6 vs. 29.8±5.9 ml/kg/min, p<0.05; HR: 152 ± 16 vs. 142 ± 15 b/min, p<0.05). Pulmonary ventilation, respiratory exchange ratio and blood lactate were similar in both trials. Plasma adrenaline and growth hormone during and 1 hour after exercise were similar in both trials, while nor-adrenaline was higher during constant intensity exercise (p<0.05). Significant time effects were found for all cardiorespiratory, lactate and hormonal parameters. Conclusions: Constant and alternating intensity exercise of the same mean intensity and duration provoked similar changes in terms of stress and blood- lactate, while VO2 and HR responses and nor-adrenaline concentration were higher when exercise intensity was constant, suggesting that constant exercise impose greater demand on the cardiovascular system.