Miranda Fuentes C.1, Ibacache Saavedra P.2, Cano Cappellacci M.3, Opazo Díaz E.3, Rojas Montero J.C.4
1Universidad Andrés Bello, Kinesiología, Viña del Mar, Chile, 2Universidad de las Américas, Departamento de Morfología y Función, Viña del Mar, Chile, 3Universidad de Chile, Departamento de Kinesiología, Santiago, Chile, 4Univesidad de las Americas, Departamento de Morfología y Función, Viña del Mar, Chile

Background: Maximum oxygen consumption (VO2 max) is considered the best measure of cardiorespiratory fitness (CRF) and exercise capacity. However, the evaluation of VO2 max requires great effort by the subject, which is not recommended for patients that present increased risk due to their pathologies. Thus in patients with obesity it is suggested the use of submaximal protocols to assess CRF. To avoid such risk in patients with obesity, we have proposed a method of assessing CRF using constant and moderate loads, called kinetics of oxygen consumption, which can be very useful To assess the CRF of a patients with obesity without taking risky tests involving physical demand. Currently, there are no publications related to their use in patients with obesity.

Purpose: The purpose of this study was to Evaluate the relationship between kinetics of oxygen consumption using a constant and low workload with VO2 peak in patients with obesity.

Methods: 26 patients with obesity (92% women) were evaluated, with a mean age of 34 years old and body mass index (BMI) of 35.5 kg/m2. CRF was evaluated by determining the VO2 peak using a Cortex Metalyzer 3b equipment with a cycle ergometer protocol, which began with six minutes pedaling a load of 0.5 W/kg of body weight, later increasing the load in 20 to 25 W every 2 minutes. The stop criteria of the test was to reach 85% of maximum heart rate (MHR= 220- age in years), reaching a 1.1 or higher respiratory quotient (RER), perceived exertion >7 in the modified Borg Scale of 0 to 10. Kinetics of oxygen consumption can be assessed through the determination of Tau, and it was calculated using the protocol described by Poole and Jones, identifying the time value needed to reach 63% of stabilization in oxygen consumption. For statistical analysis, Spearman correlation was used with the SPSS 21.0 program.

Results: The mean value of Tau was 44.3 s (SD 12.9 s). The VO2 peak expressed in absolute terms was 2.1 L/min (SD 0.6 L/min) and expressed in relative terms was 21.6 ml/kg/min (SD 3.6 ml/kg/min). For data analysis, Spearman correlation model was applied, obtaining an inverse correlation between VO2 absolute peak and the value of Tau (r =-0.455; p=0.019); however a relationship between weight relative VO2 peak and value of Tau (r = -0.326, p=0.104) was not found.

Conclusion(s): The greater is the time needed to achieve stabilization in oxygen consumption, the lower is the VO2 peak of a patients with obesity. The kinetics of oxygen consumption is proposed as a method of evaluation of the CRF in patients with obesity in which it is preferred to avoid the risk of subjecting them to high intensity evaluation.

Implications: The evaluation of the kinetics of oxygen consumption is useful for predicting the CRF of a patient with obesity that avoid the use of risky and physically demanding protocols in an exercise physiology laboratory environment.

Funding acknowledgements: This study was funded with resources of the Universidad de Chile and Universidad Andrés Bello.

Topic: Professional practice: other

Ethics approval: This research was approved by the Ethic Committee of Human Beings Research at Universidad de Chile (reg. number 149-2014)

All authors, affiliations and abstracts have been published as submitted.

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