Indeed.  However, make sure you understand how you are getting OUT
of the Canyon.  When we were there many years ago, the rafters on one
trip were dropped off at Ghost Ranch and had to hike over ten miles up
to the rim.  They weren't prepared for the hike and we met a couple
who had inadequate water (you need a gallon canteen, MINIMUM).
The man was starting to show signs of heat exhaustion.   We told him
to stay in the shade and, when we got to Indian Wells an hour later,
we sent the ranger back to look him over.
We saw the care flight heliocopter a while after that.  They were airlifting
an
average of one a day out of the Canyon in the summer back then.
That was around 15-20 years ago, before my asthma got so very
bad.  I've heard they now have a check point where they stop people
and check their gear and water supply before they let them go on
down.
Good idea.

Sue

Hydration is very important - especially as asthmatics can dehydrate
faster.

Here are some tricks to stay healthy in the desert:

1) Avoid sodas and sugary drinks.  (Your body will use all the liquid
in the soda to convert the sugar.)
2) Get one of those 'Camelback' hydration systems.  Wear it and use
it.
3) You want to drink 1 quart of water an hour while you are hiking or
in the sun.  A trick to tell if you are drinking enough water is to
see if your urine is clear.  
4) Do not skip any meals.  You can throw your electrolyte balance out
of whack by drinking water without eating in the desert.
5) Drink water.  Limit yourself to 2 'sports drinks' a day - one at
noon and one about 1800.  (Helps with electrolyte balance.)
6) Avoid all alcoholic beverages for 1 day prior to 1 day after your
trip.  
7) Get about 7 of those restaurant style packs of saltine crackers.
8) If you get a headache - that is the first warning that you are in
trouble.  Cease all activity, get into the shade and start drinking
_sips_ of water while _nibbling_ on the crackers.  Continue doing this
until you need to urinate.  (The crackers will help prevent nausea.)
9) If you become nauseated, continue as above while somebody seeks
immediate medical attention.  (This is time to call '911.')

And my final advice:

10) Drink water
11) Drink water
12) Drink water
13) Drink water
14) Repeat items 10 to 13

--
In every generation the world has produced enemies
of human freedom.  They have attacked America because
we are freedom's home and defender.  The commitment
of our fathers is not the challenge of our time.
President George W Bush - Sept 14, 2001

We flew around the canyon for an hour and a half in a one engine five
seater.  It was late in the day and calm: a beautiful sight.  There is a
natural rock formation going fom the base of the canyon almost to the
rim.  At the top it looks like the Parthenon in the rough. They call it
the Temple of Shiva.  

Toward the end of the flight I asked the pilot if he ever experienced
turbulance in the canyon.  He said "You wouldn't believe it unless you
were aboard."  Guess we were lucky.

Heard they discontinued the flights.  Is this true?