Btw, let me state that I'm no expert on this stuff, although I have read a bunch of stuff and put 2 and 2 together on some other stuff.

Let me revise what I said above, about peeing out the water as fast as you drink it if you don't add any salt. That's not quite true. When you sweat a lot, you are losing more water than electrolytes (salt/sodium, etc). The electrolytes in your sweat is not as concentrated as the electrolytes in your blood. The consequence of this is that even though you are losing electrolytes, the CONCENTRATION of electrolytes in your blood increases. You have less electrolytes but it is more concentrated because you're losing so much water. So, if you drink just plain water, then to a certain point you are diluting the concentrated electrolyte back to normal (although the total volume of your blood will still be below normal)... if you drink after that, then you begin to dilute it below normal and that is when your body will start to compensate by removing the water and creating urine.

From what you've said, you need to address 3 problems:
* dehydration
* electrolyte loss
* energy intake

I think it's easiest to look at dealing with dehydration first (although I really don't have too much to say about it) because that is what should be driving how much you drink and then look at the other 2 areas in that context.

Dehydration: In hot weather and when you are working hard (i.e. sweating a lot) you need to drink early and often. But you don't want to drink too much, although that probably won't be a problem in hot weather. Last winter, I was all gung-ho with my bottles of home made sports drinks. I needed the energy but it turned out I didn't need all the water. That was when I had to stop to pee frequently. And that was when I started making my own energy gels. I had a single bottle of sports drink and a flask of gel. That did the trick. But now that it's warming up I need to drink more and more fluids just to remain hydrated and don't need to rely on the gels as much.

So, rehydration (and fluid intake) is dependant on fluid loss. Fluid loss results from several factors. Sweating. Even in cold weather you may have sweat loss. When you first start exercising fluid flows into your exercising muscles from your blood. Respiration - you breath out water vapor. Normal metabolism and urine production.

Electrolyte loss: These are the electrolytes that you lose in your sweat. Remember, that in reagrd to electrolytes, your sweat is less concentrated than your blood. Above, we talked about restoring the lost fluid. You drink enough to restore the lost fluids. You also need electrolytes (mainly sodium/salt) to restore those that have been lost. But how much, you might ask... Basically, it should be a similar or somewhat less concentration as in your sweat which is less than the concentration in your blood. It actually has nothing to do with the carbohydrates or how much you weigh or anything like that. And it actually has little to do with how much you sweat. If you sweat a lot, then you need to drink more, but because you are drinking more you will be getting more electrolytes. So to answer your specific question, the concentration of sodium should be a ratio to the water... but if you are sweating more you will actually be consuming more per hour because you will be (or should be) drinking more.

How much? After all that, I've got to confess that I really don't know. I've looked at the nutritional information for a lot of sports drinks and I see a wide variation. And I think that it varies a lot by individual. Some people have saltier sweat than others. In my mixes, I use 1/5 of a teaspoon of salt per 24 fluid ounces of drink. I also add a dash of Morton's Lite Salt which provides potasium and magnesium (as well as sodium). It seems to work for me, but I will continue to look for additional information in this area. At this point, I know that it's important to restore electrolytes, but I suspect that an amount like I am using is 'good enough' and even if it isn't perfect the consequences aren't going to be significant.

Energy intake: This is actually pretty much independant of the other 2 problems. Except if you aren't drinking enough to get the energy you need, as I experienced last winter. In that case I supplemented my fluid intake with gels. Energy bar s can be used too. Or whatever... I used to eat pretzels.

Remember that a maximum concentration for your maltodextrin in the water is between 6 and 8 percent. With higher concentration, the water from your blood will be sucked into your intestines to dilute the sports drink before it is absorbed, delaying the absorption and leaving you with a very uncomfortable bloated feeling.

Also, you might also want to use dextrose (glucose) in your mix. I'm not sure why, though... I never even considered not using it. I think it will be absorbed faster than the maltodextrin. And I suspect it will provide a better tast that just maltodextrose and fructose. You might want to get a small bag and experiment.

Incidentally, here's the ratios of the main ingedients (by weight) in my bulk mix:
- Maltodextrin - 13
- Dextrose - 9
- Fructose - 10
I don't think there is anything special or magic about these ratios, other than the fact that I read a bunch of stuff and adjusted the ratios here and there... I don't think anything needs to be precise. It seems to work for me but I may adjust them in the future.

I also make a recovery drink, the same as above but adding protein (whey protein isolate... or something like that) in the following ratio:
- Protein - 6

To make 24 fluid ounces of sport drink, I use 2 ounces of my bulk mix and add the following:
Salt - about 1/5 teaspoon
Morton lite salt - dash
calcium - about 1/8 teaspoon
Vitamin D - a few drops
unsweetened Koolade - a tiny bit

I'm still experimenting, so I still actually weigh out the 2 ounces of mix, but in the future I'll probably use some kind of scoop that is an accurate approximation of 2 ounces. It's not rocket surgery.

(I add the calcium and Vitamin D because I have osteoporosis... but some/many (?) sport drinks do add calcium because it is lost in our sweat and it can be significant.)

When I make the recovery drink, I use a little less than 2 1/2 ounces of the mix with the protein.