Warm water immersion

1. Warm water immersion has no effect on biomarker responses to exercise-heat stress in humans.

   “there was no day × time interaction for any biomarker (all P > 0.05)”

   Human trialacute exercise-heat stress tests before and after acclimationblood∼40°C; rectal temperature maintained at ∼38.5°C for the final 60 min7 consecutive daysmalesn = 12

   Seven days of warm water immersion modulate baseline fluid-regulatory hormones without altering acute multisystem physiological stress responses in older males

   American journal of physiology. Regulatory, integrative and comparative physiology·30 Jul 2026

More on Biomarker responses to exercise-heat stress

1. Warm water immersion decreases lipopolysaccharide-binding protein in humans (−22% (95% CI −37 to −3%; P = 0.026)).

   “whereas neutrophil gelatinase-associated lipocalin and lipopolysaccharide-binding protein decreased by 24% [-40, -4; P = 0.023] and 22% [-37, -3; P = 0.026], respectively.”

   Human trialresting concentrations in habitually active older malesblood∼40°C; rectal temperature maintained at ∼38.5°C for the final 60 min7 consecutive daysmalesn = 12

   Seven days of warm water immersion modulate baseline fluid-regulatory hormones without altering acute multisystem physiological stress responses in older males

   American journal of physiology. Regulatory, integrative and comparative physiology·30 Jul 2026

More on Lipopolysaccharide-binding protein

1. Warm water immersion decreases neutrophil gelatinase-associated lipocalin in humans (−24% (95% CI −40 to −4%; P = 0.023)).

   “whereas neutrophil gelatinase-associated lipocalin and lipopolysaccharide-binding protein decreased by 24% [-40, -4; P = 0.023] and 22% [-37, -3; P = 0.026], respectively.”

   Human trialresting concentrations in habitually active older malesblood∼40°C; rectal temperature maintained at ∼38.5°C for the final 60 min7 consecutive daysmalesn = 12

   Seven days of warm water immersion modulate baseline fluid-regulatory hormones without altering acute multisystem physiological stress responses in older males

   American journal of physiology. Regulatory, integrative and comparative physiology·30 Jul 2026

More on Neutrophil gelatinase-associated lipocalin

1. Warm water immersion increases renin in humans (+68% (95% CI 29 to 120%; P < 0.001)).

   “Repeated warm water immersion increased resting renin by 68% [95% confidence interval: 29, 120; P < 0.001]”

   Human trialresting concentrations in habitually active older malesblood∼40°C; rectal temperature maintained at ∼38.5°C for the final 60 min7 consecutive daysmalesn = 12

   Seven days of warm water immersion modulate baseline fluid-regulatory hormones without altering acute multisystem physiological stress responses in older males

   American journal of physiology. Regulatory, integrative and comparative physiology·30 Jul 2026

More on Renin