Figures & data
Figure 1. Predicted environmental limits at which fan use is either beneficial (white area), or of marginal benefit (light gray area), or detrimental (dark gray area) for young adults (left panel) and the elderly (right panel). The green dashed lines represent the baseline environmental conditions of our protocol (42°C, 30% humidity). The red dashed lines represent the environmental conditions at which an increase in heart rate (HR; 42°C, ∼55% humidity) and internal body temperature (Tcore; 42°C, ∼65% humidity) occurred during a step-wise increase in relative humidity. The circled numbers indicate the peak outdoor conditions for 10 of the most severe heat waves in the past 20 years: (1) Washington, DC, 2012 (day); (2) Paris, France, 2003 (day); (3) Newark, NJ, 2011; (4) Chicago, IL, 1995; (5) New York, NY, 2006; (6) Chicago, IL, 1999 (day); (7) Washington, DC, 2012 (night); (8) Chicago, IL, 1999 (night); (10) Paris, France, 2003 (night). Modified with permission from Jay et al.Citation5
