Relationships between Self-Reported Health Related Quality of Life and Measures of Standardized Exercise Capacity and Metabolic Efficiency in a Middle-Aged and Aged Healthy Population

• Published in: Quality of life research 2003-08, Vol.12 (5), p.575-582
• Main Authors: Lindholm, E., H. Brevinge, C.-H. Bergh, U. Körner, K. Lundholm
• Format: Article
• Language: English
• Subjects: Aged; Efficiency; Efficiency metrics; Exercise; Exercise Tolerance; Female; Health Status; Health Status Indicators; Health surveys; Heart Rate; Humans; Male; Metabolism; Middle Aged; Oxygen; Oxygen Consumption; Pulmonary Gas Exchange; Quality of Life; Questionnaires; Self report; Self reports; Stress tests; Studies; Walking
• ISSN: 0962-9343; 1573-2649
• DOI: 10.1023/A:1025034919526

Background: The purpose of this study was to evaluate to what extent self-reported health related quality of life (HRQL), assessed by the Swedish standard version of the Medical Outcome Study Short-Form 36 (SF-36), is related to measured exercise capacity and metabolic efficiency in a cohort of healthy subjects from the Gothenburg area of Sweden. Material and methods: Individuals were invited to take part in the evaluation where HRQL was compared with the maximal power output expressed in Watts assessed during a standardized treadmill test with incremental work loads. Whole body respiratory gas exchanges (${\rm CO}_{2}/{\rm O}_{2}$) were simultaneously measured. Estimate of metabolic efficiency was derived from oxygen uptake per Watt produced (ml${\rm O}_{2}/{\rm min}/{\rm W}$) near maximal work. Results: The health status profile in the current population largely agreed with normative data from an age- and gender-matched reference group, although some measured scores were slightly better than reference scores. Males and females had a similar relationship between energy cost (ml${\rm O}_{2}/{\rm min}$) for production of maximal work (W), while the regressions for maximal exercise power and age were significantly different between males and females (p < 0.01). The overall metabolic efficiency was the same in individuals between 40 and 74 years of age (10.4 ± 0.07 ml${\rm O}_{2}/{\rm min}/\text{Watt}$). Maximal exercise power was only related to the SF-36 subscale physical functioning (PF), but unrelated to other physical subscales such as role limitations due to physical problems, good general health and vitality. There was also a discrepancy between measured maximal power and PF in many subjects, particularly in males who experienced either intact or severely reduced PF. Conclusions: Our results demonstrate that simultaneous measurements of self-reported and objective measures of PF should add a more integrated view for evaluation of therapeutic effectiveness, since the overall correlation was poor between objective and subjective scores among individuals.