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

Qual Life Res. 2003 Aug;12(5):575-82. doi: 10.1023/a:1025034919526.

Abstract

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 (CO2/O2) were simultaneously measured. Estimate of metabolic efficiency was derived from oxygen uptake per Watt produced (ml O2/min/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 O2/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 O2/min/ 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Exercise Tolerance*
  • Female
  • Health Status
  • Health Status Indicators
  • Heart Rate
  • Humans
  • Male
  • Middle Aged
  • Oxygen Consumption*
  • Pulmonary Gas Exchange
  • Quality of Life*