Abstract
Objective: This study examined the association between use of heating and sedentary behavior (SB) and physical activity (PA) at home among Japanese adults in winter.
Methods: This cross-sectional study was conducted from November to April from 2014 to 2017. Participants (N=3,874) who intended to conduct insulation retrofitting were recruited by construction companies from 46 prefectures excluding Okinawa Prefecture and wore an accelerometer on their waist for 2 weeks. The association between heating use and log-transformed SB and PA at home was analyzed using a sex-stratified multilevel model (random-intercept model) with 3 levels; day-level variables (e.g., indoor temperature and log-transformed accelerometer wear time as an offset), nested within individual-level (e.g., age and body mass index), and nested within household-level (e.g., household income, number of housemates). The degree of association with the dependent variable was given by exponential transforming the unstandardized regression coefficient.
Results: Data from 3,482 participants were analyzed. In the multilevel model, not using a kotatsu was associated with about 2% shorter SB time [men: exp(B)=0.98, p=0.022; women: exp(B)=0.98, p=0.020], an about 10% greater number of breaks in SB time [men: exp(B)=1.10, p=0.001; women: exp(B)=1.11, p<0.001], and 5-7% greater PA [men: exp(B)=1.07, p=0.005; women: exp(B)=1.05, p=0.012] than using a kotatsu. Heating the changing room was also related to shorter SB time, a greater number of breaks in SB time and greater PA in men and women.
Conclusions: Not using a kotatsu and heating the changing room were associated with shorter SB and greater PA at home. Warming by heating the entire home, rather than partially heating just the living room, may decrease SB and increase PA in winter.
