Do we really need to drink eight glasses a day, or is it all just a big marketing con?
A very interesting study was carried out earlier this year by sports scientists in Australia. They wanted to determine how significant rehydration with water is to an athlete's performance. They carried out a test on a number of cyclists but, crucially, gave each of them varying levels of water, including none at all.
The cyclists, rehydrated through a drip, had no idea how much water they were taking on board. The results show no differences between the performances of those who had plenty of water and those who had none.
Does this suggest our 'need' for water intake is something of a myth? Is it something we're convinced is 'good' for us without any scientific evidence?
There are about 12 brands of bottled water in Ireland and most are represented by the Bottled Water Association of Ireland, which is a division of the Beverage Council of Ireland.
You may remember when Ballygowan water was first introduced to the Irish public way back in the mid 1980s.
Gay Byrne held up a bottle of it on 'The Late Late Show' and informed us that it wouldn't be a passing fad, but that many of us would be buying water in the not too distant future.
"Buying bottles of water!", we spluttered incredulously into our mugs of tea, "Only an eejit would pay for bottled water, go on out of that," we said.
"According to figures online (Irish Guild of Sommeliers website) Ballygowan now produces around 75 million bottles of water per year.
The bottled water industry in this country is worth an estimated €250m annually.
The Beverage Council of Ireland has reported that sales of bottled water grew by 46pc over the past 10 years. (Indeed, the situation prompted one Fine Gael senator to conduct some research into drinks prices in pubs, and discovered that mineral water costs more per litre, on average, compared to stout and beers.)
We've certainly become a nation of water guzzlers, but some people appear to be hydrating themselves just a bit too much.
This water guzzling could be another example of people buying into one of the great health myths of our time: a person needs to drink eight glasses of water a day.
Worse still, excessive consumption can lead to decreases in productivity levels. How? All that time spent dashing to the toilet.
So how many glasses of water a day does a person really need to drink and are we drinking so much bottled water because we're being influenced by advertising and marketing?
Aidan Goggins is a qualified pharmacist, nutritionist, consultant in modern medicine and co-author of award winning 'The Health Delusion'.
"There is a lot of mythology around the need for water consumption; a lot of it is simply made up," he says.
"You could argue that around 70 years ago the notion came about that people need to take in about two or two and a half litres of water a day.
This idea was reinforced about 40 years later and the water companies – those selling bottled water – jumped on this idea.
That's how the 'eight glasses of water a day' principle came about.
"However, what became deliberately overlooked is that water requirements do not have to come from bottles of water, but, aside from alcohol, can be included in anything we consume that contains water."
Aidan explains that we are already taking in plenty of water even though we may not realise it.
"We get the water our bodies need from food types, tea, coffee, juices and so on.
If you were to rank water intake according to the best sources, drinking water would actually come fourth or fifth on the list.
Fruit and vegetables, as a source of water, would be top," he claims.
"They can be up to 90pc water, and included also will be minerals and electrolytes which help balance hydration, and of course all the other benefits that fruit and veg would bring.
"Furthermore, because they are a food source of water, you get a slower release of water which is more beneficial.
It's not true that tea and coffee dehydrate in regular consumers; the water contained in these drinks counts just as much as any other source of water.
"In fact coffee, despite the bad press it gets as being a toxin in the body, actually works as a detoxifier having beneficial effects on liver function and disease.
"Tea and coffee are also great sources of water because they're derived from plants – which we would not otherwise get in our diets – that have major health benefits for common diseases such as Alzheimer's, cancer, diabetes and heart disease."
How have we arrived at the situation where the need for drinking water daily and regularly – from bottles or the communal water cooler – is an accepted wisdom? Aidan explains that it is simply a matter of the hard sell from bottled water producers.
"You have to hand it to the marketing people behind bottled water don't you?
"It's fantastic what they do, but every scientific study or research into the matter debunks the supposed need for a certain amount of water each day. In fact, and there have been reports about this, too much drinking water can upset the mineral balance in the body.
"As your body pushes to get rid of excess water you can then lose valuable minerals and electrolytes; too much water isn't good for you.
"Of all the health messages out there today, the water consumption message is probably the least needed or relevant.
"Even if you're taking in a lot of water, or whatever the supposed 'recommended amount' is, and you feel better, I'd say that most likely is not because of the water.
"Perhaps it may just be that you've convinced yourself that you will feel better.
"The American Institute of Medicine has a very simple rule: drink to thirst.
"So obviously if the weather is hotter or you've been exercising, then you'll need more water.
The notion that you need to pre-empt thirst somehow is totally wrong.
If people applied the 'drink to thirst' rule you'd see a lot less bottles of water being carried around by people who simply don't need them."
While people aren't doing any major damage by consuming a certain number of glasses of water each day, it does seem that the belief in the benefits may be unfounded.
The positive conclusion I draw is that instead of going to the water cooler I'll now justifiably put the kettle on instead. Tea, anyone?