Are we drinking enough? A scientific review.

[nowster]

journals.physiology.org/doi...

'Despite the seemingly ubiquitous admonition to “drink at least eight 8-oz glasses of water a day” (with an accompanying reminder that beverages containing caffeine and alcohol do not count), rigorous proof for this counsel appears to be lacking.'

TL;DR: There's no published scientific evidence behind the "eight glasses a day" mantra. Coffee, tea and beer (in moderation) do count towards the total.

They concede that this is for people who do only mild exercise. For "vigorous work and exercise, especially in hot climates" extra fluids are needed.

It's an interesting read.

[John_W Graduate]

I'm 5'8" - just and a mere 10st. Always been skinny. The idea I should be chugging 2-3 litres of water down me every day seems a bit daft - I'd be wanting to pee most of the time. And if I want to enjoy tea and the odd coffee and maybe a beer or 2 on top of that ...

Instead, I rely on the tried and trusted method of anyone medically trained (that's not me btw) which is the pee test - what colour is it? If it's light - good to go. Dark ? Have a glass or 2 of water or tea or some fruit.

[Hidden in reply to John_W]

It's the same as the calorie levels bandied about. 2,000 per day for women. Sometimes, someone takes the trouble to say 'the average woman'. My maintenance calories, as a small woman, and without exercise, are 1,200 per day.

Luckily I can eat another 150/day doing CT5K, tho...

😄😄😄

[backintime Graduate]

I did a "water challenge" before I started C25K a couple of years ago and I upped my water intake to 3 litres a day (spread over all day and not chugging loads down in one go).

I really did notice a difference and my body adjusted to the extra intake (and expulsion) relatively quickly.

I am awake around 18 hours a day, I sleep around 6

So 3 litres of water spread over 18 hours is a litre every 6 hours, so measurement-wise, one of those little half litre bottles of water every 3 hours. Honestly, it didn't seem so much and the difference I felt in my body and saw in my skin made it worth it. My skin was clearer and my legs felt less heavy. I had a natural tendency to drink most of my water throughout the day and taper off in the evening after dinner, so I never had to wake up in the night to pee (that would have stopped me drinking that much water for sure )

I dislike coffee and tea, so it was only water or herbal infusions. I did abstain from alcohol for the month of the challenge but I do now have an occasional glass of wine (or rum) or beer now and again.

I no longer drink 3 litres but I have maintained a higher than average (compared to my colleagues and friends) water consumption and I don't regret it.

[tmbtrain Graduate in reply to backintime]

Thats really interesting to hear you saw a big difference. I've tried in the past to do 2litres but didnt see a change. Maybe 2l wasnt enough.

[backintime Graduate in reply to tmbtrain]

Maybe it depends how much you were drinking before?

I know I wasn't drinking enough before, I could (and still can probably) get through the day on one glass of water.

Drinking a lot of water also makes me less hungry and greatly "dilutes" sugar cravings as I am hardly drinking any diet soda (I used to drink a can a day at least) or anything sweet at all. My circulation /water retention has also improved (although this could be a simple consequence of getting up and down to fill my water bottle and a couple of extra trips to the loo).

I definitely notice the difference on run days if I haven't drunk enough water the day before (I don't think it's the placebo effect as it's usually when I'm running and thinking that it feels harder than normal that I start to count what I drank the day before)

But at the end of the day, you have to do what works for you

[nowster Graduate in reply to backintime]

I also definitely wasn't drinking enough when I started C25K. I was getting dehydrated when running, with the usual effects: very dark pee and constipation.

My usual daily intake would be less than a litre. Fine if you're not doing any exercise, but not if you're working up a sweat for half an hour or more.

Before I got on this forum I was treating the constipation with bulking fibre drinks (Fybogel) and as a side-effect adding to my hydration. When I read the FAQ I had a lightbulb moment and suddenly everything made sense.

[backintime Graduate in reply to nowster]

yes, it's much easier to poop when you're hydrated

[tmbtrain Graduate in reply to backintime]

I was drinking 5-6 cups of coffee a day then trying to drink some more water on top of that to make 8. I love that it might be able to reduce sugar cravings I'd not heard that effect before. A friend of mine drank 2l a day for 6 months before her wedding and said it made her skin really clear but it was a habit that she could easily slide out of so never became automatic. I think I might try increasing again esp now with running and see if I can get an effect.

[roseabi]

For info, 8 x 8 American fluid ounces is about 2 litres

[nowster Graduate in reply to roseabi]

1892.7 mL to be precise. 🤓

[Hidden]

I drink a lot. I always have done. I love the taste of water. In the UK atm, its quite cold and overcast so I have been drinking more tea.

[Irish-John Graduate]

I'm part Camel or something. I always seemed to have water when everyone else was running low, it was often remarked on. I still drink less than I figure I should, but I just don't get all that thirsty.

Here's the thing though - when I do get a bit too much thirsty and drink a mug or two of water or whatever liquid, and makes no difference if I do it fast, slow, incrementally, hot or cold or anywhere in between, I instantly sweat for a minute or two. Never have been able to discover why that happens - you'd think being slightly dehydrated the body would want to comserve fluid.

[backintime Graduate in reply to Irish-John]

Maybe your body was waiting for reinforcements before sweating ?

[Irish-John Graduate in reply to backintime]

Good point!

[Hidden in reply to Irish-John]

It might be hydrating the skin.

[DylanTheRabbit Graduate]

I worked in a hospital for a while, we had to fill in fluid charts for most of our patients. As well as all types of drinks, we also counted milk on cereal and wet foods like jelly and gravy.

[Hidden]

I read something a while ago about someone who died through drinking too much water.

Each time you pee you get rid of waste but also some salts and nutrients that are required by the body. Unless they are being replaced it can make you ill. The old saying about too much of a good thing is bad for you definitely true with drinking a lot of water. I had a quick search but could not find the article I was reading but did find the article below which covers it.

thehealthy.com/hydration/dr...

[nowster Graduate in reply to Hidden]

It's quite a common problem. Some runners have overdone it, for instance.

Another common reason (as discussed in the article) is an interaction with the illegal rave drug Ecstacy, which has the simultaneous effect of increasing thirst and decreasing urine production.

[Hidden]

Thanks for this post.

Luckily, my body has never left me in a state of dehydration.

Despite what a doctor once told me.

He was one of 'those' doctors.

LOL.

[nowster Graduate in reply to Hidden]

I was in a state of dehydration at very the beginning of doing C25K. My pee got very dark and I had constipation. I had barely been drinking enough anyway and I didn't increase the amount I was drinking to compensate for the exercise. At the time I didn't make the connection.

[Hidden in reply to nowster]

I'm surprised you didn't get thirsty, or didn't notice it, or didn't respond to it!...

[SueAppleRun Graduate]

Yes, a very interesting read, and backs what i’ve always thought that yea is still fluid in the form of flavoured water, although a glass of cold water or two on return from a hot run is very welcome

[Hidden]

Tosh, and tosh. So glad to hear it! 😂😂✌️