So, something that’s been bothering me a while is the apparent contest between blood pressure and hydration.
I have hypertension, I sweat a lot and when I do my blood pressure reduces and approaches healthy levels. Hypertension treatments can commonly use diuretics.
Hydration is obvs important in endurance events, but rehydrating is fundamentally going to raise my blood pressure again.
As I can’t objectively measure pressure or hydration in races or training really, how can one know what the “right” level of dehydration is?
Get rid of the hypertension.
Hydrating during exercise was a big part of my physiology dissertation. While our experiment design wasn’t great I read a lot about this. The research at the time suggested that people rarely replace the missing fluids during exercise and do so in the hours after. If people replace what they lose through sweat they generally feel like they have drunk too much and are uncomfortable. But thirst should be your guide, is probably the best thing. You wouldn’t want your BP reduced because you’re dehydrated for a prolonged period.
Thanks, so we’ll be partially dehydrated most likely even when drinking a good amount - but what makes you say this bit given that diuretics are prescribed to do that?
I’m thinking of a scale of dehydration here.
Diuretics are only one type of medication used and depends on comorbidities that prevent use of ACE inhibitors, angiotensin blockers or Ca channel blockers. Then one would be in a state of mild dehydration I guess but I meant, voluntarily keeping yourself dehydrated is not a good idea.
Emails with the BHF that might be of interest:
“Initially when you sweat and become dehydrated your blood pressure will come down, but as the dehydration continues a chemical called vasopressin is released and this is done to preserve the fluid in the body. The effect of this chemical is to constrict the blood vessels and therefore increase the blood pressure.“
In short, still not a good idea to dehydrate to reduce bp