hydration needs

superbad50

hi ,

just wondering how much fluids should i be taking in cycling to blanchardstown and back, travelling from crumlin village - approx 50 min out and back. and also would i be best opting for isotonic fluids and if so what brands are the most. do not want to be exhausted before i start my day off

tnx all

Hanley

If you want to be really anal about it, weigh yourself before leaving in your jocks, bring the scales with you, weigh yourself when you get into work in your jocks. The difference is how much fluid you lost.

0.5kg down? That's about 500ml of water

1kg down? you're down about 1,000ml (1 litre) of water

shootermacg

Is that pre or post dump?:D

Hanley

shootermacg wrote: »

Is that pre or post dump?:D

At home, post.
In work, pre.

superbad50

I think that might be a bit to much hassle but cheers. I was thinking more along the lines of replacing lost energy , carb wise post exercise

metamorphosis

You do not need any isotonic fluids for a 50min cycle. Water will do the trick. Do not force water down, drink when you want to. Use your urine colour as a standpoint for your hydration levels - it should be lightly straw coloured, if it smells strong or is yellow or orange, drink that mofo water.

Nwm2

Hanley wrote: »

If you want to be really anal about it, weigh yourself before leaving in your jocks, bring the scales with you, weigh yourself when you get into work in your jocks. The difference is how much fluid you lost.

0.5kg down? That's about 500ml of water

1kg down? you're down about 1,000ml (1 litre) of water

It is not recommended in general that you have to replace your fluid loss during the course of the workout.

Hanley

Nwm2 wrote: »

It is not recommended in general that you have to replace your fluid loss during the course of the workout.

1) It’s a 50 minute cycle in Ireland… it doesn’t matter. He’s not going to lose a significant amount of fluid. Dehydration only effects performance when around 2% of bodyweight and upwards is lost – that’s 1.5kg for a 75kg guy. 1,500ml of sweat on a 50 minute cycle is not going to happen.

2) Yes, it’s ‘recommended’ but practically would you take your concentration off the roads in Dublin!? I wouldn’t.

3) He actually asked how much does he need to take on to replace lost fluids, my method gives an indiciation as to how much he’s losing on an average day (assuming relatively constant weather, humiditiy and clothing levels, any change in which will probably be mitigated by a change in the other leading to a relatively flat body temp level on most days).

So, in response to your question, which is completely unrelated to the thread – yes. You are better off taking in fluid as you lose it. But below a set level (approx 2% of bodyweight) it’s not really going to matter at all.

Khannie

You're all mad.

Half a litre should do it. Have some more if you're thirsty. I generally add some salts (I use lo-salt for potassium and sodium) to drinks that I use to replace sweat.

Carbs + 50 minute cycle? I'd say probably 350 odd calories depending on your weight. It's a guess though.

superbad50

tnx guys for all your responses . the last time i cycled home i felt weak and had to stop off for some sugar , the water was just not doing it for me , obviously there are other factors, ie maybe i hadnt enough to eat on that day plus was feeling under the weather. the bike also i was using was not the best and if i can remember it was pretty windy out so i was expelling alot more energy than normal

thanks for all the replies. i will keep some etc carbs with me just in case for energy related purposes

Nwm2

Hanley wrote: »

1) It’s a 50 minute cycle in Ireland… it doesn’t matter. He’s not going to lose a significant amount of fluid. Dehydration only effects performance when around 2% of bodyweight and upwards is lost – that’s 1.5kg for a 75kg guy. 1,500ml of sweat on a 50 minute cycle is not going to happen..

Absolutely, yet your answer gives a different impression by talking about the method and that type of loss.

Hanley wrote: »

2) Yes, it’s ‘recommended’ but practically would you take your concentration off the roads in Dublin!? I wouldn’t.

No, it's not recommended that you finish all workouts the same weight at which you started.

Hanley wrote: »

3) He actually asked how much does he need to take on to replace lost fluids, my method gives an indiciation as to how much he’s losing on an average day (assuming relatively constant weather, humiditiy and clothing levels, any change in which will probably be mitigated by a change in the other leading to a relatively flat body temp level on most days).

Maybe you should carefully re-read his question to see exactly what he asked.

Hanley wrote: »

So, in response to your question, which is completely unrelated to the thread – yes. You are better off taking in fluid as you lose it. But below a set level (approx 2% of bodyweight) it’s not really going to matter at all

Incorrect.

Hanley

Absolutely, yet your answer gives a different impression by talking about the method and that type of loss.

He asked about fluid, I answered in terms of fluid, namely water, and a way of gauging what’s been lost. Fairly straight forward and simple, no?

If I was answering in terms of carb based drinks and how much of them to consume, I’d have said so, and specifically qualified it by saying different drinks will have different amounts of carbs in grams per milliliter.

Anyway, it’s pretty unlikely he’s going to make any major impact on glycogen levels with that amount of exercise assuming a normal enough diet during the rest of the day. Do you not agree?

No, it's not recommended that you finish all workouts the same weight at which you started.

I didn’t say that it was, don’t misquote me. I mis-read your original point and my position was that it may be beneficial to rehydrate during a workout, in general. At no point did I mention full hydration.

Maybe you should carefully re-read his question to see exactly what he asked.

I obviously can’t read so. I answered based on my interpretation of the question, and did so pretty clearly. Maybe you can tell me what he meant? Or maybe the question itself just wasn’t clear.

Incorrect.

That’s helpful. Maybe you can say why, because unless the studies I’ve looked have been superseded (which is possible), that’s the level at which dehydration begins to effect performance.

Or maybe you’re stating that peri-workout rehydration has no effect on performance?

Khannie

superbad50 wrote: »

tnx guys for all your responses . the last time i cycled home i felt weak and had to stop off for some sugar

Maybe take a sugary drink with you on the ride then. Eventually you'll find you don't need this any more.

Nwm2

Sorry Hanley, I was yanking your chain a bit. :rolleyes:

He asked an apparently straightforward question about how much he should drink in a 50 min cycle (answer: maybe little or nothing depending on the intensity. Drink if you feel thirsty, no need for calories in it. If I'm doing a 50 min low intensity cycle, I usually won't bring a bottle at all. If I'm cycling a hard 50 min time trial you can bet I'm having at least water during it, and probably some High-5 carbs mixed in. The effect of the calories might be as much psychological/neuromuscular as physiological.).

You seemed to be to be answering a somewhat different question - as you put it "He actually asked how much does he need to take on to replace lost fluids". Your answer could be read as implying replacing exactly how much you lose, with water.

Anyway, ignoring who said what, on the general topic of hydration recommendations are moving (back?) towards drinking when you're thirsty:


http://www.trainingbible.com/joesblog/2008/09/hydration-and-exercise-part-1.html

Also, more recently:

http://sweatscience.com/

It’s official: drinking to perfectly maintain fluid levels makes you slower, not faster. At least that’s the message in a new British Journal of Sports Medicine meta-analysis, from Eric Goulet at the University of Sherbrooke. What’s new here is the recognition that there’s a fundamental difference between treadmill or bike tests where you continue at a set pace until exhaustion, and “real world” time trials or races where you cover a given distance as fast as possible. Many of the classic studies underlying the orthodox view (that losing more than about 2% of your body mass hurts endurance performance) are time-to-exhaustion tests:

These tests with no known end points are unrepresentative of out-of-door exercise conditions faced by field athletes and therefore possess a very low ecological validity [Goulet writes], which therefore question their value and relevance in the design of fluid intake guidelines aimed at maximising endurance athlete performances.

To address this point, Goulet reviewed five studies that looked at dehydration in self-paced cycling time trials — and his conclusions were starkly different from the conventional wisdom. On average, subjects in these studies with an average dehydration of 2.2% of body mass actually had a non-significant improvement in performance of 0.06% compared to subjects who drank enough to roughly maintain body mass (losing an average of 0.44% body mass).

Drinking according to the dictate of thirst was associated with an increase in [time trial] performance compared with a rate of drinking below (+5.2±4.6%, p=0.01) or above (+2.4±5.0%, p=0.40) thirst.

Is this shocking? Well, it agrees with what Tim Noakes has been arguing for several years. It also agrees with real-world data like this study from a marathon in France, which found that sub-3:00 finishers lost 3.1% of their body weight, 3:00-4:00 finishers lost 2.5%, and slower-than-4:00 finishers lost only 1.8%. Will it change anyone’s mind? Goulet is hopeful: he says the findings should “contradict and abolish the old and much-believed dogma stating that ‘during prolonged exercise it is of capital importance to drink ahead of thirst, otherwise it is already too late.’” I’d like to think that’s true, but I suspect it will take quite a few new studies before opinions start to shift.

Hanley

Alright... good post. Now we're talking. Makes sense in a race situation anyway.

But the question is, is that only applicable in race situations? If you don’t rehydrate during training is there a chronic debilitating effect which impacts recovery and subsequent training performance?

Khannie

That quote is the greatest load of self serving rubbish I've read in ages. What's to say that they lost more sweat because they were fitter and therefore worked harder (producing more heat, requiring more sweat)? Maybe the guys who took a long time had longer to drink the fluids? In a marathon situation, the people who walk the most are obviously going to cross the line more hydrated because their rate of heat production is going to be significantly lower. and so on, and so on, and so on.

Nwm2

Khannie wrote: »

That quote is the greatest load of self serving rubbish I've read in ages. What's to say that they lost more sweat because they were fitter and therefore worked harder (producing more heat, requiring more sweat)? Maybe the guys who took a long time had longer to drink the fluids? In a marathon situation, the people who walk the most are obviously going to cross the line more hydrated because their rate of heat production is going to be significantly lower. and so on, and so on, and so on.

Now, now, let's not over-react. There's plenty even worse self serving rubbish quoted around here:).

Anyway, the 'meat' of my post was to a 3-part Joe Friel series that quoted several studies and also to the study that Mr Sweatscience referred to.

So, let's debate the scientific studies, not the colour commentary.

Nwm2

Hanley wrote: »

Alright... good post. Now we're talking. Makes sense in a race situation anyway.

But the question is, is that only applicable in race situations? If you don’t rehydrate during training is there a chronic debilitating effect which impacts recovery and subsequent training performance?

Quite possibly - not sure if there are studies that directly look at it that way.

But the post exercise rehydration might/should give adequate recovery?

Khannie

Nwm2 wrote: »

So, let's debate the scientific studies, not the colour commentary.

Deal. I'll have a read of them later.

superbad50

best of luck lads , sorry if i am to blame for some of you falling out. ha . you all seem to be speaking a different language but very interesting points .

best of luck