Many hot-weather health issues center around proper hydration. My last post discussed how much water we should be drinking, and whether or not fluids other than water counted towards that volume. I finished up by mentioning that in addition to the amount we consume, we need to take into account how quickly we process those fluids, and what should (or should not) be in the fluids we are taking to maintain proper hydration. 

Have you ever downed a liter of water in a single gulp and still felt thirsty? Part of our sense of hydration levels depends on how fast we are able to process those fluids through our digestive systems and out into our bloodstream and our cells. Even with a perfect digestive system and perfect kidneys, it can take us between several hours and a couple of days to regulate a huge increase in fluid intake -- especially if it's done in large bolus-like intakes (like a bottle of water in one gulp) rather than gradually, like basal insulin. One factor this is the speed at which water is able to pass through our digestive systems and into the large intestine, where it is absorbed; another is the body's need of additional water to flush out lactic acid build-up from exercise. And of course kidney function -- a bugaboo for many of us who have lived with diabetes for some time -- can be a severely limiting factor. Personally, I find I can drink gallons of water at a renfaire and yet not pass the excess until the following morning -- and the day after a hard ride, I'll often weigh a pound or two more than a strict calorie balance suggests I should.

Another part of the hydration picture is the balance of minerals in our system -- in particular, the electrically-active elements known as electrolytes. These elements, such as sodium, potassium, calcium, and chlorine, often combine to form salts -- salts which are excreted in sweat and tears. They are also key factors in how our nerves, muscles, and organs function. If we sweat and do not replace electrolytes, our bodies can react with anything from mild discomfort to a fatal heart attack. In order to prevent this from happening, we are often advised to alternate pure water with electrolyte-replenishment beverages.

Most sports drinks (like Gatorade, Powerade, and their artificially-sweetened sister, Propel) try to position themselves as electrolyte-replenishment beverages. While they do contain often-significant amounts of sodium and reportable levels of potassium, they are more often sources of quick glucose (needed when one is burning 500 to 1000 calories an hour) and can be responsible for our blood glucose levels spiking even more than they might from dehydration alone. In addition, many supermarket-friendly "sports beverages" do not replenish any electrolytes other than sodium and some potassium. While these are the elements whose excessive dilution is most deleterious to our immediate health and well-being, we also lose chlorine, calcium, magnesium, chromium, manganese, and a host of other minerals. I'm not sure if it's a standard term or not, but I refer to beverages and powders which include that entire shopping list as "full-spectrum electrolyte replenishment drinks". Sadly, they're damnedly difficult to find -- and while I can afford the caloric hit of a technical sports drink like Cytomax or HEED if I'm going to be out on a long bike ride, the rest of the time both the calories and the sugars are an issue.

I do have a personal favorite -- Ultima Replenisher, which is sweetened with stevia. It's not a fizzy drink, which means I can put it in my sports bottle without having it spurt all over me on the road. Most of its competitors (like Emergen'C) are effervescent or fizzy, which should be fine if you're dealing with the heat, but not worried about the agitation of a ride or run. Some of the athletes on TuDiabetes suggest Endurolytes from Hammer Nutrition (a sports-nutrition label) or Nuun (another sports-nutrition brand), which I find disproportionately high in sodium. Of course if you need the calories as well as the electrolytes, skim milk and soy milk are great options, as are electrolyte-rich foods such as bananas and oranges, broccoli, and many other richly-colored fruits and vegetables -- just remember to test often, and (if appropriate) adjust your insulin to cover.

Before you make any changes to your hydration regimen, please consult with your medical team. There are a number of personal variables that can influence what you need to be consuming, and how much of it, to keep healthy and in correct fluid and electrolyte balance. Like our oral medications and insulins, what's appropriate for one of us could be downright deadly for another. Come up with a plan, a set of guidelines, and the appropriate replenishments for you.