Relationships between physical fitness level and Health-Related Quality of Life in obese adults: a pilot study

Introduction: If recent epidemiologic studies suggested that higher levels of physical activity (PA), cardiorespiratory and muscular fitness may offset much of the excess of mortality risk that is associated with overweight and obesity (Blair, 2004; Fogelholm, 2010) and may counteract the adverse cardiovascular profile (Artero, 2012), only PA participation has been linked to health related quality of life (HRQoL) in obese adults (Herman, 2012). Currently, there is insufficient evidence available regarding the relationship between physical fitness level with HRQoL in this special population. Therefore, the aim of the present study was to investigate the impact of ardiorespiratory (V’O2max) and muscular (iMVC) fitness on HRQoL in obese adults. Methods: 10 obese adults (6 women 4 men, mean age 27.6±6.3 years; BMI 39.9±5.8 kg/m2; MVPA 37.9±36.6 min/day; V’O2max 30±6 mL/kg/min; iMVC 15.2±2.6 N/kg) were involved in the study. To assess V’O2max and iMVC, they performed a maximal treadmill test with indirect calorimetry (Quark CPET, Cosmed, Italy) and a maximal isometric strength test using two force platforms (Twin Plates, Globus, Italy) fixed on a horizontal leg press (Technogym SpA, Gambettola, Italy). HRQoL was measured with the Short-Form 36 Health Status Survey (SF-36v2) that provided the physical (PCS) and the mental (MCS) component summary score. Results: The overall average PCS and MCS scores were 53.6±6.7 and 45.2±6.9, respectively. Regression analysis, adjusted for age and BMI, revealed that neither V’O2max nor iMVC were related to a higher HRQoL. Only lower BMI was associated with higher vitality, a sub-dimension of MCS (F-value 5.966; p<0.05). Discussion: The absence of associations between V’O2max and iMVC with HRQoL may be due to a higher PCS score when compared with the mean reference values of a population of moderately obese subjects (reference PCS=45.99±12.1), and, in contrast with Doll et al. (2000), a higher PCS score compared with MCS values. In accordance with Fontaine (2001), a higher BMI was associated with a lower vitality score. Future studies are needed to gain a better insight into these findings