Hydration is a tricky one, especially for the novice runner. For years, we have been told “drink even though you may not be thirsty,” and I don’t necessarily disagree with this entirely. However, you can overhydrate, and it is a serious problem. The dangers with over-hydration include hyponatremia, which is basically water intoxication and the depletion of electrolytes in your body. On the flip side, if you become dehydrated (generally losing 2 – 3 percent of your body weight in fluids, your body starts to over work, which forces your heart to beat faster, making it more difficult for you to keep up with the cardiovascular demands of running.

Factors that influence hydration:

  1. Sweat Rate
  2. Environment/Weather
  3. Training intensity
  4. Duration of activity
  5. Age
  6. Body size
  7. Body temperature
  8. Genetics

Keys Facts about Hydration

  • Sodium is an important nutrient during intense exercise, especially for athletes exercising in the heat for long durations.
  • Maintaining blood volume is key to keeping fluid balanced in the body.
  • A DECREASE in blood volume results in DEHYDRATION and an INCREASE in blood volume results in OVER-HYDRATION.
  • Sweating is simply the primary means of the body to release heat, and as the core body temperature rising so does the volume of sweat, which increases the risk of dehydration if fluids are not replaced.
  • Sweat is 99% water and 1% representing other substances includes electrolytes such as sodium, chloride, calcium, magnesium, & potassium, and smaller amounts of other minerals; which are equally important as water itself. Muscles & neurons rely on electrolytes for activity. Muscle contraction is dependent upon the presence of calcium, sodium, & potassium.
  • NOTE: There isn’t a one size fits all hydration plan. Check your sweat rate & urine color to keep it in check!

Signs and Symptoms of Dehydration:

  1. Confusion
  2. Weakness
  3. Increased Heart Rate
  4. Dizziness
  5. Headaches
  6. Nausea
  7. Chills
  8. Decreased sweating
  9. Higher rate of perceived effort
  10. Dark yellow urine

Signs & Symptoms of Over-Hydration:

  1. Confusion & Inattentiveness
  2. Drowsiness
  3. Delirium
  4. Blurred Vision
  5. Muscle Cramps & Twitching
  6. Paralysis on one side of body
  7. Poor Coordination
  8. Nausea & Vomiting
  9. Rapid Breathing & Weakness
  10. Sudden weight gain

Sweat Rate Calculation:

  1. Weight before exercise – Weight after exercise = ____lb
  2. Weight Difference X 16oz = ____oz
  3. Amount of fluids consumed during activity + oz = _____Total fluids lost
  4. Duration of activity = _____hours
  5. oz lost/duration of activity = _____sweat rate (oz/hr)

(As little as 2% fluid loss can impair performance. In fact, a 3% loss can cause a 10% loss of strength and an 8% loss in speed.)

Just like I’ve said hydration takes PRACTICE just as much as your running training does, and every person is NOT created the same. So here are a few guidelines to start with, adjust according to how you feel.

  1. General rule of thumb, drink about half your body weight in ounces/day. Example: 120lb person would drink about 60oz of water per day. (Eat fruits & veggies too; about 80% is water and they’re packed with antioxidants, which boost muscle recovery & immunity)
  2. During training drink about 15 – 20 ounces/hour. If you are an intense salty sweater consider upping the ounces. (This is only for runs OVER an hour – most athletes won’t require much during runs/workouts under an hour)
  3. Thirst is a great indicator that tells you, “hey gimme liquids”; however, it’s not always the best in certain climates (cold or extremely dry). My recommendation is PRACTICE your hydrating like everything else, and if you are thirsty then drink, but if you are thirsty every other mile then it could be because you haven’t acclimated to the particular climate yet.
  4. Take the sweat test to get some answers while you practice your hydrating training. It estimates how much fluid you lose on your runs. I suggest doing this in all weather conditions and be sure to note it in your training log; particularly focusing on the weather conditions that you will be racing in at your race pace. (Tempo Runs) See formula above.
  5. Urine test – If your urine is like apple juice get your butt in gear and start drinking, if it’s a pale yellow then you have been appropriately hydrating.
  6. One thing we don’t want to do is chug our liquids, because that could possibly leave you feeling nauseated, and you could experience that sloshing feeling in your tummy. So instead of thinking, have your watch do it for you!! Set your watch to beep every 15 minutes as a reminder to consider your thirst.
  7. Drink both water & a drink that contains both a carbohydrate & electrolyte combo. This is for any run longer than 45 min – 1 hour. The carbs help to sustain your energy levels, & the electrolytes will help in the prevention of hyponatremia.
  8. ALWAYS chase gels, chews, or blocks with WATER! Be sure to take in both slowly. Your belly will thank you!

It’s all about PRACTICE! Just like we train our muscles and cardiovascular system, we can train our belly too! NEVER TRY ANYTHING NEW ON COMPETITION DAY!!