Comfort Fanger model! Adaptive comfort model. Adaptive comfort model and health: indoor temperature variation! Thermal comfort and health!

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1 Comfort Fanger model NUTRIM SCHOOL FOR NUTRITION TOXICOLOGY AND METABOLISM MAASTRICHT Bruin vet en de consquenties voor het thermisch binnenklimaat 5e Kennisdag Bouwfysica Nederlands Vlaamse Bouwfysica Vereniging Delft, 20 juni 2013 Wouter van Marken Lichtenbelt Based on heat load only. The physics of heat transfer. No inclusion of human physiology. Standard population; not valid on individual level. Only valid in steady state situations and near thermo neutrality Adaptive comfort model Adaptive comfort model and health: indoor temperature variation selected temperatures outside PMV predicted comfort range Is regular exposure outside the PMV zone (outside the ASHREA standard zone) Comfortable? It seems yes (adaptive model) Healthy? Only recently results available (EOS LT results). Which temperatures do we actually select? Large individual variation. Why? Can we change the selected temperatures (thermal behavior)? Does that affect energy consumption in buildings/dwellings? 4 DeDear and Brager 1998; DeDear et al., 2001; van Marken Lichtenbelt, Arch Sc Rev 2013 Built Environment Thermal Environment Thermal comfort and health Energy consumption buildings Comfort zone = healthy zone? hypothesis comfort Obesity Ageing Human Energy expenditure Health Behavior 5

2 Physiology and health Thermoneutral zone Thermoneutral zone TCZ mild cold Ambient temperature C Energy Balance Metabolic Research Unit Maastricht (MRUM) LivingMitochondrial outside uncoupling thermoneutral MUSCLE zone Fat storage Maastricht Respiration Chambers 9 Mild cold: nonshivering thermogenesis (NST) Mild cold: non-shivering thermogenesis Non-shivering thermogenesis Shivering thermogenesis Not uncomfortable (after acclimatization) Increase in human body energy expenditure large individual variation (0 30 %) CIT % of RMR Van Ooijen et al. Br J Nutr

3 Decreased non-shivering thermogenesis in elderly nonshivering thermogenesis lean versus obese Blunted cold-induced thermogenesis in obese subjects 20 C 30 C lean obese ΔEnergy expenditure (W/m2) 1 hour mild cold 48 hours mild cold o Young adults Elderly 1 *: p< Wijers et al. Obesity 2010 Claessens-Van Ooijen et al. Obesity 2006 individual variation Blunted or absence of non-shivering thermogenesis in Skin temperature Skin perfusion Blood pressure obese Heart rate elderly Blood parameters Brown fat Wijers 2010; Kingma et al. Acta Physiologica. (2011) Kingma et al. Acta Physiologica. (2011) Nonshivering thermogenesis in adults high 40 Some identified physiological and health parameters Summary Combining metabolic studies and PET/CT scans Brown fat versus white fat 24 male subjects (age:18-32 y; BMI kg/m2) Thermoneutral 1h (22 C); mild cold 2h (~16 C) 18F-FDG -PET/CT (2 mci (74 MBq) Indirect calorimetry Thermometry DXA 18

4 Brown fat activity Thermoneutral versus cold Thermoneutral Brown Fat and obesity Mild cold Van Marken Lichtenbelt et al., New Engl J Med Van Marken Lichtenbelt et al., NEJM 2009 Cold acclimatization Cold acclimation experiment following Davies 1961 Preliminary results 9 females, 8 males 10 day cold exposure by water suit 6 h/d C Dynamic 18F-FDG-PET/CT before and after before Van der Lans et al. J Clin Invest, in press Cold acclimation (10 days) thermal sensation and comfort Van der Lans et al. JCI in press After 10 days 6 h/d 14 C Van der Lans et al., JCI in press 22 In conclusion Brown adipose tissue in adult humans 23 Cold activated BAT is negatively related to BMI and BF Blunted in obese and elderly Cold acclimation recruits BAT BAT volume increases Cold induced BAT activity increases Thermal comfort increases 24

5 Thermoneutral zone Shifts TCZ mild cold Van Marken Lichtenbelt & Kingma, Arch Sci Rev 2013 Need to exercise our thermoregulatory system as part of a healthy lifestyle By regular exposure outside the thermoneutral zone: Increase energy expenditure capacity (negative energy balance) Increase brown fat thermogenesis (also other health benefits: diabetes type 2) Obesity Need to exercise our thermoregulatory system as part of a healthy lifestyle (use it or lose it ) By regular exposure outside the thermoneutral zone: Increase energy expenditure capacity Increase resilience to more extreme weather conditions Healthy ageing Is a dynamic indoor climate realistic? u Transient variation u Local variation EOS LT LowEx Thermal comfort under transient (17-25 C) condition Main result: acceptable comfortable Young adults Elderly Temperature [ o C] Time [min] 480 Schellen et al., Indoor Air 2010

6 EOS LT2003 LowEx Uniform versus non-uniform General conclusion, based on EOS LT3001 and EOS LT2003 A dynamic indoor climate is feasible: Characteristics: u Individualized u Temperature training (resilience) u Healthy (brown fat; blood perfusion) u Not uncomfortable u Productive u Save energy in buildings Cold floor/displacement ventilation: non-uniform environments: more comfortable Schellen et al., Physiology and Behavior, 2012; Schellen et al., Energy and Buildings, 2013 De Haas & Partners Individual-oriented information technology for energy efficient living User Centered Energy Reduction INTEWON UCER AgentschapNL EOS LT TKI-GB Dynamic LED lighting, thermal comfort, health, and energy savings in buildings Advanced sustainable lighting solutions. Partnership program STW en Philips Main objective: study the effect of light intensity and color on thermal acceptability and thermophysiology 35 Acknowledgements NUTRIM SCHOOL FOR NUTRITION TOXICOLOGY AND METABOLISM MAASTRICHT AgentschapNL: Piet Heijnen; Paul Ramsak Cauberg Huygen: Peter Op t Veld; Ad van der Aa; Hans Cauberg MU/TUE: Boris Kingma Lisje Schellen Christel Jacquot Arjan Frijns Anton van Steenhoven Patrick Schrauwen Boudewijn Brans Guy Vijgen Anouk van der Lans Maarten Vosselman Christel Jacquot Sander Wijers Jamie Drossaerts Jaap Teule Joost Vanhommerig Funded by Nicole Bouvy NL Agency - EOS LT 03001; LTEOS 10033; AgentschapNL LT; LT TKI; STW ZonMW- TOP Maastricht University Medical Center + NWO-ZonMW-TOP; EU-FP7 DIABAT