Assessing Thermal Comfort in Nursing Home Using Heart Rate Measurement

Abstract

The ratio of dementia amongst the residents in nursing homes makes it practically impossible to conduct traditional questionnaire-based comfort analyses. Besides, there are uncertainties in the residents’ cognitive capabilities to respond to a questionnaire, since residents with dementia can be very sensitive to the smallest changes in their everyday life. Therefore, there is a need for alternative investigation methods when conducting comfort studies in nursing homes, such as indirect measurements or observational studies. Based on a pilot study in two Danish nursing homes, this paper demonstrates how thermal comfort can be estimated using the heat balance-based comfort equation of P.O. Fanger, using the metabolic rate of residents calculated from a simple heart rate measurement. This estimate is then compared to the Predicted Mean Vote (PMV), using standard metabolic rates to investigate how well the estimated thermal comfort fits the PMV theory. The proposed method, based on heat rate measurements, has minimum impact on the test persons and requires no cognitive activity. Furthermore, it enables a more dynamic perspective on thermal comfort. The study results indicate that the metabolism of elderly people (+75 years of age) living in nursing homes can be at a lower level than what can be counterbalanced by a lower heat loss, as it is normally assumed. The conclusion is that the proposed method is promising but needs further development and validation concerning the conversion of heart rate to metabolism and how to account for age-related physiological changes.