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Adequate Hydration For Long Runs

By | Dr. Pat Kulpa

No matter how well prepared you may be for a run - not being properly hydrating before, during and after will have major consequence.

Here is some advice on adequate hydration while training and running especially longer runs like half marathons:


  • If you are behind your fluids and dehydrated at least 1 Liter if you are already thirsty before exercising.
  • Signs of being dehydrated include decrease energy, muscle cramps, dry mouth, headache, nausea, chilling, and awkwardness.
  • Hydrating the few days before the race is important and drinking 2 hours before the race is important. (It will also save you from waiting long lines at the portable potties near the start of the race).
  • Drink EARLY at the water stations (even if you are NOT thirsty) will save you and give you energy and better performance at the end of the race. Even if you have to stop a second to get your water down without gulping air do it. Some runners may train with a camel back (hydration packs) to sip water continuously while running.
  • If you drink 16oz of water, expect 20 minutes later to urinate if you well hydrated. If your urine is clear you are drinking enough.
  • If you haven’t trained with electrolyte drinks supplied by the race, do NOT drink them at the race. You may experience abdominal cramps and diarrhea since you are not used to their hyperconcentration.
  • The best bet is to drink water during a race unless you bring your only electrolyte drink with you at the race.

The environment around you while running (wind, rain, sun, humidity, altitude) also makes a difference.

  • Wind may cool you off but the convection also is a source of sweating and water loss.
  • The starting air temperature and humidity will also clue you on your risks of getting dehydrated.

Rule of thumb to remember is that one should think twice before running when the combination of air temperature and humidity is greater than 160. Officially per ACSM - American College of Sports Medicine, no distance races greater than 10k should be conducted if  combination of air temperature, humidity and sun raises WBGT temperature above 82 degrees F...

Sponsored races will monitor this for your safety and this should not be an issue October 16th.

Your running attire may also play a role in raising or lowering your core body temperature. Stay hydrated and cool. Remember that weather may be unpredictable the day of the race, so pay attention, dress appropriately and come prepared to change if necessary.

Looking forward to seeing you on Race Day!

Happy Training!

~ Dr Pat