Intestinal epithelial injury and inflammation after physical work in temperate and hot environments in older men with hypertension or type 2 diabetes

Lee, Ben J., Flood, Tessa R ORCID: https://orcid.org/0000-0001-8897-0957, Russell, Sophie L., McCormick, James J., King, Kelli E., Fujii, Naoto, Amano, Tatsuro, Notley, Sean and Kenny, Glen P. (2025) Intestinal epithelial injury and inflammation after physical work in temperate and hot environments in older men with hypertension or type 2 diabetes. Experimental Physiology. ISSN 0958-0670

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Abstract

We tested whether older adults with well‐controlled type 2 diabetes or hypertension, compared with age‐matched adults without chronic disease, exhibit greater intestinal damage, microbial translocation and inflammation during exertional heat stress. Twelve healthy men (age 59 years, SD 4 years), nine with type 2 diabetes (age 60 years, SD 5 years) and nine with hypertension (age 60 years, SD 4 years) walked for 180 min at 200 W/m2 in temperate conditions (wet‐bulb globe temperature 16°C) and high‐heat stress conditions (wet‐bulb globe temperature 32°C). Serum intestinal fatty acid binding protein (IFABP), plasma soluble cluster of differentiation 14, lipopolysaccharide‐binding protein (LBP), interleukin‐6 and tumour necrosis factor‐alpha were measured pre‐ and postexercise and after 60 min recovery. Total exercise duration was lower in men with hypertension and diabetes (p ≤ 0.049), but core temperature did not differ. All markers increased more in heat versus temperate conditions (p < 0.002). In the heat, individuals with type 2 diabetes had greater postexercise increases in IFABP [+545 pg/mL (95% confidence interval: 222, 869)] and LBP [+3.64 µg/mL (1.73, 5.56)] relative to healthy control subjects (p < 0.048), but these resolved after recovery. Despite reduced exercise duration, hypertensive individuals showed similar increases in IFABP and LBP to control subjects. Our findings suggest that older workers with well‐controlled type 2 diabetes or hypertension might have greater vulnerability to heat‐induced gastrointestinal barrier disturbance and downstream inflammatory responses when compared with otherwise healthy, age‐matched adults during prolonged exercise in the heat.