Effects of acute heat exposure on monocyte phenotype following exhaustive exercise: An ex vivo study

This study aimed to evaluate the effects of ex vivo whole blood heat therapy on monocyte inflammatory response following exhaustive exercise in young individuals.

Eight recreationally endurance trained individuals (27.2 ± 3.1 years old, VO₂Peak 53.1 ± 2.1 mL/kg/min) performed a strenuous step-up/step-down protocol until exhaustion. Blood samples were collected pre and post exercise and incubated 37 °C or 40 °C during 2 h. Flow cytometry was used to assess TLR-4 expression, NF-kB activation, mitochondrial membrane potential and TNF-alpha expression in CD14+ monocytes.

Post exercise, TLR-4 expression and NF-kB activation increased at 37 °C (p < 0.001), but heat therapy at 40 °C significantly reduced these responses (p < 0.01). MMP decreased after exercise at both temperatures but was significantly lower at 37 °C than 40 °C (p < 0.05). TNF-a levels showed a trend toward returning to baseline with heat therapy.

Ex vivo heat therapy reduces monocyte mediated inflammation after exercise, induced muscle damage, suggesting its potential as a recovery strategy to strenuous exercise sessions.