Are we all dehydrated? Here's what you should really be drinking

In a shocking addition to the usual hellish challenges, Richard Madeley was recently rushed from the I'm a Celebrity castle suffering a 'mystery illness.'

It turned out that the presenter, 65, was suffering from lack of sleep, and dehydration - and much to his disappointment, was forced to leave the show having broken the contestants' covid-safe 'bubble'.

Of course, health comes first - but how did he become so badly dehydrated? The show has its little cruelties, but depriving contestants of water isn't one of them.

Madeley told The Telegraph, "I got into my bunk and suddenly felt detached and discombobulated. 'Funny turn' really is about the only way of describing it.

"I think I got dehydrated, that's all it was."

He said, "Dehydration if anyone's ever suffered from it is actually quite disturbing. We were having very, very long days and sleeping quite late. I don't think I'd got to bed 'til about 4.30 in the morning. And I knew I was feeling thirsty.

"I'm quite bad at remembering to drink water. And as I snuggled into my sleeping bag and it was freezing, I remember thinking, 'I haven't had a big drink for a while. I'll do it when I wake up.'

"And the next thing I knew I was sitting there babbling, talking nonsense.

"I woke up, I didn't know where I was, what was going on and I could hardly string a sentence together," he went on.

"I went to the hospital had all the tests you can imagine, and I've got 100 per cent clean bill of health - by then I'd had a cup of tea and a drink of water. And I was back on the rails."

Read more: 6 common dehydration symptoms

The NHS explains: "Dehydration means your body loses more fluids than you take in. If it's not treated, it can become a serious problem."

Symptoms include thirst, dark urine, dizziness, tiredness, dry mouth and eyes, and not needing to pee.

It's generally easily avoided, unless you're trapped somewhere, eg on a long journey, with no water available, or are someone hot, where sweating makes it much easier to become dehydrated without realising.

Signs of serious dehydration include a weak, rapid pulse, ongoing dizziness, exhaustion, confusion and even seizures.

But how much should we really be drinking per day? The old 'eight glasses of water' myth has been busted, but many of us are confused as to whether it has to be water and nothing else, or if tea, coffee and soft drinks count too. (Unfortunately, alcohol is very dehydrating - so doesn't count as fluids.)

"In order for our brains and other bodily functions to be operating optimally we need to stay hydrated," explains The Gut Expert, Nishtha Patel.

"Water is needed for cushioning the joints, protecting organs, regulating body temperature and electrolyte balance.

Watch: Shipwrecked mother saves children by breastfeeding them but dies of dehydration

"In addition it helps to carry nutrients and oxygen to your cells, flushes out bacteria from your bladder and is crucial for preventing constipation, stabilising heart beat and normalising blood pressure."

There's no instant answer to exactly how much you should drink, she explains.

"It depends on where you live, (the hotter the climate the more you sweat and the quicker you need to replenish), it also depends on how much you weigh and and how active you are.

"Other factors such as kidney disease or medication also mean that the amount of water needed for each individual vary from person to person."

The general rule (for a healthy adult), she explains, is four to six eight-ounce glasses per day, or about a litre to a litre and a half. Obviously, if you're taking heavy exercise or in a very warm environment, you should drink more accordingly.

And it's good news for herbal tea lovers.

"You can also get water though foods such as cucumber, tomatoes, watermelon and other high-water foods," says Patel. "Herbal teas (non caffeinated) also count towards your water intake."

A word of warning too - even if you're determined not to 'do a Madeley' and accidentally forget to drink, go easy. Drinking too much water is dangerous, too.

Read more: A third of Brits don't drink any water: The health benefits they're missing out on

"If you exceed three litres, you can risk depleting the body of essential minerals as they can get flushed out," says Nishtha Patel.

If you do find yourself dehydrated, sachets of rehydration salts such as Dioralyte can fix it fast. And don't forget to drink a big glass of water.

Watch: Drink up to avoid dehydration this festival season