23/10/2025
This data hit home for me personally – I used to have extremely high cortisol levels (I know because I tested them), and my water-drinking habits left a lot to be desired.
A recent study from Liverpool John Moores University found that adults who habitually drink less than 1.5 litres of fluid a day have significantly higher cortisol responses to stress – over 50 % higher than well-hydrated peers.
I of course knew there was a link, but 50 % higher – woah!
And 1.5 litres of water isn’t exactly a tiny amount either.
The researchers monitored 32 healthy adults over seven days, split into low and high fluid intake groups. Participants then completed a controlled psychosocial stress test while hydration was measured via urine colour and concentration.
Despite similar anxiety and heart rate responses, only the low-fluid group showed a marked rise in cortisol.
These findings suggest that even mild, habitual under-hydration can exaggerate stress responses, potentially impacting long-term metabolic and cardiovascular health.
I know, tiny study and all that, but certainly worth knowing about, don't you think?