The cool weather of May and June that kept the snow
in the high country has given way to summer temperatures,
lush wildflowers and rivers full with snow melt.
It brings to mind the need to stay hydrated.
Maintaining water balance, in addition to preventing
dehydration, helps our tolerance to heat, altitude
and cold challenges. Hydration is important to health,
yet over-hydration can make us ill. The mantra of
hydrate, hydrate and hydrate is heard throughout
the wilderness world. This can be good, and it can
be bad. As in anything, moderation is a good habit.
How much water should I drink? What temperature
is best? What about salt and sugar? There are many
answers to these questions depending on your physiology,
activity and environmental conditions, and of course,
on who you ask. The hydration needs of a sedentary
and an active person will differ. We exercise at
different rates, in heat and cold, dry air and humid
air, at sea level and at altitude. Crafting one recommendation
Competitive athletes can become very sensitive to
exactly how much fluid they need. Some even weigh
themselves before and after exercise to help figure
out how much water they lose. We take the middle
of the road and follow a recommendation from the
American College of Sports Medicine to replace a
minimum of 250cc of water for every 20 minutes during
exercise, of a general target of 4-5 liters a day
backpacking in the mountains. As you gain experience,
you can fine-tune your intake. Monitor your urine
output for color and quantity — dark urine
is a sign of dehydration, as are fatigue, irritability,
poor thinking, thirst and headache.
We sip hot and iced drinks, we drink cool and warm
beverages. There is some data favoring the absorption
of cool over warm beverages, but the differences
would only impress a research scientist and probably
don’t have a noticeable impact in the real
Likewise, most sports drinks have acceptable concentrations
of sugar. Palatability seems as good a choice point
as any. People argue whether sugar should be simple,
complex or polymerized carbohydrate, and whether
sports drinks provide enough sodium. This is primarily
of interest to the competitive athlete. On a wilderness
expedition, I don’t get my nutrition by gulping
a drink or an energy gel at a race rest station.
My daily carbohydrate intake is based on meals and
The emphasis on hydration has brought to light the
dangers of over-hydration and hyponatremia — low
blood sodium. The prominent examples in the press
have been in Grand Canyon hikers and marathon runners.
The hikers drink lots of water and don’t balance
this with food — a source of electrolytes.
The marathon runners are diligent in stopping at
every drink station and ingest more fluid than they
are losing through sweat.
Of critical importance in deciding if someone may
have hyponatremia is an accurate history. Relatively
little salty food intake combined with relatively
high fluid intake, say several liters in the last
few hours, should make you highly suspicious.
Prevention, to quote wilderness medicine guru Buck
Tilton, is “a matter of being sensible, which
is so often the case.” Drink lots, yes, but
eat salty foods regularly while exercising in heat.