Hot, Hazy, Humid? Hydrate!
by Dr. Ann L. Engelland
(July 3, 2008) When you just think it can’t
get any more humid, the dark clouds roll over, thickening
the air until it feels like we are breathing through scuba
gear. Football camp has begun on the Mamaroneck High School
field across the street from my office and I marvel/cringe
at the droves of kids in complete regalia, wondering about
body temperatures inside their gear. For teams practicing
on the new turf fields, the risk is significantly higher to
athletes, and coaches and parents need to be aware of the
increased risk of heat stress.
This hazy, hot, humid weather is not likely to let up any
time soon, and we need to stay mindful throughout the summer
of the effects of heat. Some knowledge and a bit of preparation
will prevent a lot of problems.
Why is this so important? Heat injury can be life threatening
and young people are more vulnerable than adults. If that
isn’t convincing enough for your high school athlete,
a reminder that athletic performance diminishes when a body
is a mere 1-2% dehydrated might help. Considering that a person
doesn’t normally even perceive thirst until 3-5% dehydration,
it is clear that performance and well-being can drop quickly
if hydration is not attended to.
Following are some guidelines for fluid management:
Pre-training (or exercise):
Correct the deficits from the previous day’s workout
2-3 hours before: 12-16 ounces
Shortly before: 8-12 ounces
This is the most important time, of course. The recommendations
8-12 ounces every 15-20 minutes in high school athlete
4-6 ounces every 15-20 minutes in younger athlete
For most athletes, if the workout is less than 60-90 minutes,
water is the preferred beverage.
Exceptions to this rule include the following situations:
- Athletes who have whitish salt crusting when they sweat,
indicating a heavier than usual sweat salt content, should
drink sports drinks (for example, Gatorade)
- Athletes who say they will vomit if they put water in
their stomachs can hydrate with salt/sugar drinks to speed
up gastric emptying (into the intestine that is!).
- Athletes (especially young ones) who will not adequately
hydrate if the solution is not colored, sugary, salty or
flavored may need sports drinks.
Any beverage (non-alcoholic) is fine. Alcohol is a diuretic
and will dehydrate the body further, putting it at a disadvantage
for play the next day.
For every pound of weight lost, an extra 16 ounces of fluid
should be consumed.
What about heat stress?
Heat stress can be divided into four increasingly severe
Heat cramps: very painful muscle contractions
that can look like an injury. Treatment consists of passive
stretching, ice and fluids (IV if not tolerated by mouth).
Although pro athletes try pre-game icing, it is not proven
Heat syncope (or fainting): this is also
called “finish line collapse” and happens after
an athlete crosses the line and typically stops without cooling
down gradually. Nausea and fatigue with or without fainting
are the hallmarks. The key to prevention is to “keep
‘em moving at the finish line” to encourage circulation
until the body re-equilibrates.
Heat exhaustion: an inability to continue
to exercise in the heat. Symptoms include intense fatigue,
nausea, or fainting while exercising. It is probably caused
by a combination of sodium and water depletion. Athletes competing
in events longer than 4 hours are at particular risk. These
include all day tournaments, marathons, more than one game
and/or training session in a day, etc. Treatment includes
cooling, hydration and ER evaluation if necessary. Athletes
who have experienced heat exhaustion may not be ready to return
to play for 48 hours or more after an episode.
Heat stroke: characterized by an elevation
of core body temperature rising over 40 degrees centigrade.
It is characterized by muscle and nervous system impairment
and brain symptoms such as confusion, agitation, combativeness
and seizures may be the presenting signs. Heat stroke is a
true emergency and requires EMS management; mortality up to
25% has been reported. It may take months for an athlete to
be well enough to return to play due to muscle and brain injury.
Readiness should be documented by lab tests and clinical testing
by a knowledgeable trainer or clinician.
In the Marines basic training camps, if soldiers collapse
in the heat, they are treated to the “silver bullet,”
a rectal thermometer to check core temperature and then a
large bright orange “X” spray-painted on their
backs for the duration of training as a warning that they
are at risk.
How do we prevent heat stress and injury?
A few basic rules will help prevent problems:
Acclimatization: Athletes who are planning
on sports pre-seasons in the heat of August need to acclimatize.
That means that for 4-7 days beforehand they should be out
of the air conditioning and exercising in the heat. This expands
the blood volume and charges up the sweat glands to make them
more efficient at fluid and temperature control.
Avoid/beware of “thermogenic” substances:
These are substances that increase the body’s heat and
include caffeine, typical ADHD medications, antihistamines
and Power drinks (like Red Bull).
Maintain fluid intake: This should be a
part of training before, during and after working out. Again,
alcohol has no business in a body during training. Rehydration
between workouts is often forgotten.
Avoid “high risk” conditions:
Standards and recommendations exist for determining the safety
of various combinations of heat and humidity for athletes.
Briefly, and a good rule of thumb to remember is that humidity
over 50% combined with temperature over 90 degrees means that
practice and training should be without gear and in shorts
with water breaks and rest periods every 15 to 20 minutes.
Tables for humans (and cattle, elk, poultry!) can be found
at a site of national
About those artificial turf fields?
The surface temperature and therefore the transfer of heat
to the athlete (and coaches or bystanders) is much higher
than on natural turf or even on asphalt. Surface temperatures
can be in excess of 150 degrees on a 90 degree day. Obviously
this can contribute to excessive fluid losses, burns, heat
illness, and exhaustion. Watering down these fields can bring
down the heat somewhat, but often not for the length of a
game. Coaches and school personnel will need to be better
informed and weigh the risks to their players under hot and
In summary, parents, coaches and athletes need to remember
- Young kids are especially vulnerable to fluid loss.
- Re-hydration between workouts is critical.
- Athletes should keep moving and cool down slowly.
- Any neurologic involvement suggests heat stroke and is
a true emergency.
- Acclimatization is a key to prevention.
References: Many thanks to Michele LaBotz, MD who presented
much of this information at the Sports Medicine Course of
the American Academy of Pediatrics in Vancouver in June 2008.
See also, Parents'
and coaches' guide to dehydration and other heat illnesses
in children on the National Athletic Trainer’s Association
Dr. Engelland has a practice in Mamaroneck devoted
to Adolescent Primary Care. She now accepts Aetna and
Hudson Health Plan. Dr. Engelland can be reached at