Passive heat stress might not affect the glomerular filtration rate but the trials are controversial on whether heat acclimation improves or not GFR; a trial from the US showed that permissive dehydration with heat acclimation does not induce an increase in urinary NGAL, another trial from the UK showed that heat acclimatization can reduce AKI incidence but this was not consistent in another study from the US (106–109). The gene discussed is LCN2; the disease is acute kidney injury.