Thermal sensation and thermophysiological responses to metabolic step-changes
This study investigated the effect on thermal perception and thermophysiological variables of controlled metabolic excursions of various intensities and durations. Twenty-four subjects were alternately seated on a chair or exercised by walking on a treadmill at a temperature predicted to be neutral at sedentary activity. In a second experimental series, subjects alternated between rest and exercise as well as between exercise at different intensities at two temperature levels. Measurements comprised skin and oesophageal temperatures, heart rate and subjective responses. Thermal sensation started to rise or decline immediately (within 1 min) after a change of activity, which means that even moderate activity changes of short duration affect thermal perceptions of humans. After approximately 15–20 min under constant activity, subjective thermal responses approximated the steady-state response. The sensitivity of thermal sensation to changes in core temperature was higher for activity down-steps than for up-steps. A model was proposed that estimates transient thermal sensation after metabolic step-changes. Based on predictions by the model, weighting factors were suggested to estimate a representative average metabolic rate with varying activity levels, e.g. for the prediction of thermal sensation by steady-state comfort models. The activity during the most recent 5 min should be weighted 65%, during the prior 10–5 min 25% and during the prior 20–10 min 10%.
KeywordsActivity Comfort Indoor climate Transients
This study was supported by the Danish Technical Research Council as part of the research programme of the International Centre for Indoor Environment and Energy established at the Technical University of Denmark. The authors wish to thank Professor Bodil Nielsen, University of Copenhagen, for her valuable advice on the assessment of metabolic transients.
- Fanger PO (1970) Thermal comfort. Danish Technical PressGoogle Scholar
- Fukai K (2000) Experimental study on advantages of moderate temperature and low humidity air conditioning. Annual Meeting of Architectural Institute of Japan, D2, 991–992 (in Japanese)Google Scholar
- Kashimura O (1985) Effects of wind and air temperature on some physiological reactions and thermal sensation in endurance exercise. Jap J Biometeorol 22:73–81 (in Japanese)Google Scholar
- Kjerulf–Jensen P, Fanger PO, Nishi Y, Gagge AP (1975) A new type test chamber in Copenhagen and New Haven for common investigation of man’s thermal comfort and physiological reactions”, ASHRAE Journal, January, pp. 65–68Google Scholar
- Nielsen B, Oddershede I, Torp A, Fanger PO (1979) Thermal comfort during continuous and intermittent work. In: Fanger PO, Valbjørn O (eds) Proceedings of the First International Indoor Climate Symposium 1978, Copenhagen, Denmark, pp 477-490Google Scholar
- Nishi Y, Gonzalez RR, Gagge AP (1975) Direct measurement of clothing heat transfer properties during sensible and insensible heat exchange with thermal environment, ASHRAE Trans 81:183–199Google Scholar
- Olesen B (2000) Guidelines for comfort. ASHRAE Journal, August, pp. 41–46Google Scholar