BBC News reported this week that A&E admissions are rising due to heatstroke and dehydration... but what's going on with our guts in this heat?

Right, let's talk about heatwave poo. Yep it's a thing! Either you haven't been in three days, or you're sprinting to the loo like you're Usain Bolt. There's rarely a happy medium once the temperature rises. Your gut, like every other part of you, behaves differently when it's roasty-toasty outside.

I get asked about this every summer, usually half-joking, half-panicked: "is this normal?" 

So here's the real biology behind "heatwave poos"

Two Completely Different Poos, Same Weather

Here's the annoying bit: heat doesn't just do one thing to your gut. Some people experience slow transit, others can barely leave the house because of worries of urgency and toilet dashes!

Both are heatwave-related, and both come down to the same root cause: your body is working overtime to keep you cool, and digestion isn't the priority anymore.

When you're hot, blood gets redirected towards your skin so you can sweat and cool down. That means less blood, and less energy, going towards your gut.

For some people, that slows everything right down and you become constipated. Food sits longer, water gets reabsorbed more aggressively from your stool, and you end up backed up (Bristol Stool Chart type 1 or 2).

For others, particularly those prone to IBS, that same stress response speeds the gut up instead, hurrying everything through. And speed, in gut terms, usually means urgent bathroom trips.

Same heat. Same body. Two completely opposite results. Neither one is "wrong".

Dehydrated And Asking Where Did All Your Water Go?

So you know you've been drinking more but your still feel thirsty, and a bit dehydrated? 

Well sweat is the obvious culprit. You're losing far more fluid than you realise, even just standing still in a heatwave, and a lot of that water would otherwise be heading straight into your bowels normally to help keep your poo soft and easy to pass.

Here's the sneaky part, though. When it's humid, you often don't feel as thirsty as you should, so you drink less water than you're actually losing. Then if you top up with iced coffee, a cold beer in the garden, a G&T because it's Friday and thirty-one degrees, and all of those are liquid but diuretics. Meaning they pull even more fluid out of you.

So you're dehydrated, and topping up with things that dehydrate you further, while your gut quite reasonably holds onto every drop of water it can get. Which equals constipation. 

Plain water helps, obviously. But if you've been properly sweaty, water alone won't replace the salts and minerals you've lost too, which is exactly why I get slightly obsessed with electrolytes every summer. Something like our Water Wealth does more heavy lifting than a pint glass of tap water on its own ever will. (And we're back in stock by the way!)

Then There's The BBQ Effect

If your gut goes the other way, loose, urgent, unpredictable, a heatwave brings its own reasons for that too. 

It can be that food left out in the sun turns dodgy fast. Often in the heat we're eating differently to our normal and at different times. That potato salad sitting on the garden table for three hours, the burgers that were "probably fine", the picnic that's been in a warm car boot since eleven; bacteria multiplies far quicker in heat than most of us clock.

And for lots of us, adding in more alcohol than usual, richer and fattier BBQ food, and a lot more ice-cold drinks (a sudden blast of cold can trigger your gastrocolic reflex, basically your gut's "go" signal). Upping the dairy through ice-creams or rushing your eating on the go, leading to urgency and loose stools.  

And Don't Forget Your Sleep

Heat wrecks sleep. Everyone knows this: tossing about at 2am with the windows open and a fan pointed directly at your face, achieving nothing. Poor sleep and heat stress both lean on your gut-brain axis, the two-way link between your head and your gut, meaning one struggling drags the other down with it.

If you're already prone to a sensitive gut or IBS, a run of bad, sweaty nights can be enough to tip things off balance on its own. 

What Actually Helps

Hydrate properly, and don't wait until you're thirsty to start, because by the time you feel it you're already behind. Electrolytes matter as much as plain water once you've been sweating, so don't rely on water alone to do all the work.

Go easy on the ice-cold drinks if your gut tends to run fast rather than slow; room temperature is kinder on a jumpy system.

Try to keep some structure to your meals even on holiday, because your gut genuinely likes routine, and skipping meals then eating a huge dinner at 9pm because you were at the beach all day doesn't do you any favours.

Be sensible with food that's been sitting out: if it's been in the sun for more than an hour or two, let it go, however good that halloumi looked.

And keep supporting your gut daily rather than only when it's already annoyed with you. A bit of consistency, your daily supplement, decent fibre, regular movement, tends to build the kind of resilience that copes better when the weather throws a curveball at it.

When It's Worth Getting Checked

Most heatwave gut wobbles settle down once the temperature does, and that's genuinely most of what I hear about every July. But get it looked at if things don't ease up once it's cooled off, if there's blood, if you're properly dehydrated (think dizzy, dark urine, barely peeing at all), or if pain is severe rather than just uncomfortable.

Trust yourself here. You know your normal better than anyone.

Upgrade Your Water In This Weather

When the weather turns properly hot, hydration becomes more than just drinking more water. It is about helping your body replace what it loses, supporting your energy and keeping your gut feeling comfortable too.

Water Wealth Daily Electrolytes is an easy way to upgrade your water in this weather, with electrolytes plus vitamin B12 and vitamin C to help reduce tiredness and fatigue. One scoop a day, refreshing summer fruits flavour, and a much tastier way to stay topped up when the heat is doing the most.