We evaluated enterocyte damage (IFABP), immune activation (sCD14), and inflammatory responses (TNF-α, IL-6, CRP) in 16 older adults (66-78 years) during 8 h rest in conditions simulating homes maintained at 22 °C (control), the 26 °C indoor temperature upper limit proposed by health agencies, and homes without air-conditioning during heatwaves (31 °C, 36 °C). Relative to 22 °C, IFABP was elevated ∼181 pg/mL after exposure to 31 °C (