Don't get behind in the first place. Just as there are many ways and means to take in fluids (water, sports drinks, and water-containing foods all come to mind), there are many different ways to determine adequate hydration. While some of these involve expensive laboratory and medical equipment, there's an easy and cheap way to check approximate hydration status from the comfort of your own bathroom. By simply noting the color and volume of your urine you can gauge whether you need to drink more (or maybe less). Dark-colored urine of a relatively small volume is an indication of dehydration and should signal you to drink more fluids throughout the day or during your run.
Hydrate before heading out. In general, consider following this recommendation adapted from The American College of Sports Medicine's Position Stands. Exercise and Fluid Replacement: Drink approximately 1 oz per every 10 lb of body weight 4 hours before running, and if profuse sweating is expected, drink ~0.6 oz per every 10 lb of body weight 2 hours before a run. Give yourself time to use the bathroom before you head out.
Recognize your losses. Electrolytes are lost both in sweat and in urine. Some athletes lose a lot of 'lytes while others don't, and there's wide range of the amount lost. As you can see in the table below, sodium and chloride are lost in larger amounts than potassium, magnesium, and calcium, as well. The values listed represent the amount of electrolytes contained in a liter of sweat. Keep in mind that individual athletes lose varying amounts of sweat, so use the table below as a ballpark reference.
| Mineral | Concentration in Sweat (mg/L of sweat) |
| Sodium | 460-1840 |
| Chloride | 710-2840 |
| Potassium | 160-390 |
| Magnesium | 0-36 |
| Calcium | 0-120 |
Table above adapted from Sports Nutrition: A Practice Manual for Professionals, 5th Edition.
If you replace sweat losses during the run, research shows that you’ll better optimize cardiovascular, thermoregulatory, and performance responses. Use your sweat test results to determine how much fluid you need each hour. If you’re going for a leisurely run or a run that lasts less than an hour, you can stay hydrated with water every few miles. If you’re a salty sweater, cramp-prone, or going longer than an hour, you might want try adding some electrolytes to your water. There are a few options out on the market, and a select few are listed in the table below. If you’re going for a long and taxing run, you might want to opt for a carbohydrate-containing sports drink rather than water and electrolytes alone. We’ll cover sports drink options next week, so stay tuned.
Gatorlytes- 780mg of Sodium, 400mg of Potassium; Comes in a pouch to add to water or Gatorade
Pedialyte- 244mg of Sodium, 294mg of Chloride, 183mg of Potassium; comes in ready-to-use 1L bottle, 6.8oz carton, powder packs to add to water, and freezer pops
Nuun- 360mg of Sodium, 13mg of Calcium, 25mg of Magnesium, and 100mg of Potassium; comes in multiple flavored tablets to add to water
Hammer Nutrition Endurolyte- 40mg of Sodium, 60mg of Chloride, 50mg of Calcium, 25mg of Magnesium, 25mg of Potassium, Vitamin B6, Manganese, and L-Tyrosine; Comes in a capsule of power to chase with or add to water
Salt Stick- 215mg of Sodium, 22mg of Magnesium, 11mg of Potassium, and 63mg of Vitamin D; Comes in a capsule to chase with or add to water
Mio Fit- 75mg of Sodium, 35mg of Potassium, and Vitamins B3, B6, and B12; A concentrated liquid to add to 8oz of water
