Hydration...its not just water....

The other important part of nutrition is hydration. Hydration is not just water and I don't recommend just water because 1) the body absorbs water slowly; 2) causes bloating; 3) make you use the bathroom a lot; 4) doesn't contain all the necessary nutrients such as electrolytes.

I weighed myself before and after a 3m run in 80 degree weather. I lost 4 lbs. That's actually pretty good but not really because that means, I lost 4lbs in water weight. After a long workout, when you lose a pound or two of weight, you may think this is fat loss. However, rapid weight loss is an indicator of fluid loss and not of desirable body-weight change.

Here is a good forumla: Weight loss (oz) + Fluid consumed (oz) = amount needs to be replaced during training.

Typically I drink 24oz prior my activity (when I have time) and 24-32oz per hour during and 24 oz after. Again, not just water but either Gatorade Endurance because it has a large percentage of electrolytes or IFINIT sport drink and a special recovery drink.

It is also important to note that you can OVERHYDRATE so measuring fluid intake is important.

This topic can become somewhat technical and boring so I tried to just give an overview.

N.B. I have only seen aid stations on the bike segment in half irons and they are usually every 9 miles. During the run part in every race, there is usually an aid station with water and gatorade every mile. This is the difference between triathlons and 5k/10k/half marathon/marathon. In the latter they are usually every couple of miles.