Physiology: The lowdown on low-liquids

What exactly happens when your water runs low? Dr. Mark Davenport, a Traverse City sports medicine physician who served as a team doc at the Barcelona Olympics, shares the details.

Electrolytes are very dependent on fluid status, so as you lose water, your concentrations of important elements like potassium and sodium will increase–cramping is a common result. You also sweat less to conserve water and eventually, you will not sweat with extreme dehydration.

As you become severely dehydrated, your heart rate increases as the body pumps more blood to compensate for reduced plasma. Also, your core temp increases as your body becomes less able to regulate body processes–a problem exacerbated by reduced sweating. In a survival situation, after three days without water you might still be alive, but would likely be so debilitated–possibly hallucinating and stumbling–that you would not be able to help yourself.

Gear: Clean water now

Simple, fast, light and idiot-proof–all reasons why Sandy Graham, owner of Traverse City’s Backcountry Outfitters (231-946-1339) likes the MSR MiniWorks EX water filter. His tips for any water filter: avoid silty water whenever possible and pre-filter to extend the life of the filter in the pump. (Tricks here: buy an inexpensive fuel filter and duct tape it to the water intake, or pour water through a coffee filter prior to running through the pump.)

Hydration Tips: 6 things to know about H2O

  1. Thirst is a poor indicator of hydration status–by the time you’re thirsty you’re already mildly dehydrated.
  2. Dark yellow urine is a key indicator that you need some water.
  3. Drink a half-hour to an hour before you exercise, and if you tend to cramp up, drink a lot (Davenport drinks 16 to 32 ounces of sports drink before he heads out to X-C ski).
  4. With intense exercise, like running, drink every 20 minutes or so.
  5. Keep your water handy because you are much more likely to drink it–Davenport recommends CamelBak systems or belts that hold water bottles.
  6. In survival situations, never eat dry food like bread, crackers and nuts if you don’t have water, because your body moves precious water from your blood stream into your general intestinal tract for digestion (you can go weeks without food; just a few days without water). High liquid-content foods like berries are okay.