MSHSAA GUIDELINES FOR AVOIDING HEAT-RELATED
PROBLEMS DURING PRACTICE AND CONTESTS
I. The
National Weather Bureau, on its radio station, broadcasts an hourly heat index
reading. It is strongly recommended that all schools use this service to make
judgments about athletic contests. Basically, precautionary measures should be
taken when the heat index is between 95 and 105 degrees. Over 105 degree heat
index indicates a significant danger level.
A. The
following procedures should be followed for athletic contests scheduled during
the day in hot weather:
1. The
National Weather Service, that is broadcast every hour, should be checked at
1:00 p.m. on the day before a game, as well as one hour before the scheduled
start of the contest.
2. If
heat index is stated between 95 and 105 degrees, plans should be implemented to
alter game conditions for both schools.
3. If
heat index is stated over 105 degrees, plans to postpone or reschedule athletic
contest should be implemented (both schools).
B. The
following procedures should be followed for athletic contests scheduled during the
evening in hot weather:
1. The
National Weather Service, that is broadcast every hour, should be checked three
(3) hours before schedule contest.
2. If
a heat index between 95 and 105 degrees is stated, plans should be implemented
to alter game conditions that day (both schools).
3. If
a heat index over 105 degrees is stated, plans to postpone or reschedule
athletic contest should be implemented (both schools).
C. The
following procedures should be considered for practice sessions when a
dangerous heat index level is indicated:
1. Possible
cancellation of all practice.
2. Shorter
practice time.
3. Early
morning or late evening practice.
4. Move
outside practice sessions indoors.
II. A
combination thermometer may be obtained at most hardware stores. These can be
used and kept on the fields to indicate wet bulb globe readings. A radio
weather cube is obtainable at most radio shops. This can be kept in the
Athletic Office and as mentioned, hourly heat index readings are available.
Also, weather alerts are given when indicated.
III. It is
recommended that a weight chart be kept for each individual athlete and posted
in the locker room or available area. Each athlete should weigh in at the
beginning of each practice session and weigh out at the end of each practice
session. The percentage of weight loss should be calculated. A weight loss
greater than three (3) percent should indicate potential danger of excessive
loss of body fluids during the practice sessions and accordingly, adequate
fluid replacement should be maintained throughout the remainder of that day.
Greater than five (5) percent weight loss indicates the possibility and
significant danger of developing a heat-related illness.
IV. It must
be instilled in the athletes by the coaches that water and salt replenishment
is a continual process and not a "stop-gap maneuver." Athletes
should be encouraged during hot weather to drink adequate quantities of fluid
throughout the day at home, as well as at practice sessions. During practice
sessions, water should be available to them at all times. Obviously, the
hotter, more humid weather indicates more frequent water breaks. This can be
scheduled either up to every ten (10) to fifteen (15) minutes during extremes
or if applicable, free water intake should be allowed during the entire
practice session. Salt replacement is also a daily process and the athletes
should be encouraged to adequately salt their foods during all meals. It is
not advised to use salt tablets at any time. These can actually cause more
danger, as they cause more concentrations in the stomach and can lead to
nausea, vomiting and stomach problems. Salted solutions may be given during
practice sessions but certainly water is adequate.
V. It is
recommended that practice sessions during middle and late August be scheduled
as much as possible during the early morning hours and late evening hours. For
example, 8 o'clock practice in the morning and 6:00 p.m. practices seem to be
advisable.
When
more than one practice session per day is encountered, sufficient recovery time
should be observed between sessions.
VI. It is
recommended that during hot weather in game situations several heat breaks be
called in addition to any other time-outs. It is recommended that at least
three (3) breaks per quarter be done by the officiating crew. (For Football).
VII. Heat
disorders may be classified as heat cramps, heat syncope, heat exhaustion and
heat stroke.
** These
Guidelines were adopted by the St. Louis Suburban Athletic Conference for their
member schools effective 1985-86 school year with the cooperation of Dr.
Charles Mannis and Dr. Benji Boonshaft. The guidelines have been edited by the
MSHSAA.
Heat Stress and Athletic
Participation
Frederick O. Mueller, Ph.D.
Early fall football, cross country, soccer and field
hockey practice are conducted in very hot and humid weather in many parts of
the United States. Due to the equipment and uniform needed in football, most
of the heat problems have been associated with football. Under such conditions
the athlete is subject to:
Heat Cramps -- Painful cramps involving abdominal
muscles and extremities caused by intense, prolonged exercise in the heat and
depletion of salt and water due to profuse sweating.
Heat Syncope -- Weakness, fatigue and
fainting due to loss of salt and water in sweat and exercise in the heat.
Predisposes to heat stroke.
Heat Exhaustion (Water Depletion) -- Excessive weight loss,
reduced sweating, elevated skin and core body temperature, excessive thirst,
weakness, headache, and sometimes unconsciousness.
Heat Exhaustion (Salt Depletion) -- Exhaustion, nausea,
vomiting, muscle cramps, and dizziness due to profuse sweating and inadequate
replacement of body salts.
Heat Stroke -- An acute medical emergency related
to thermoregulatory failure. Associated with nausea, seizures, disorientation,
and possible unconsciousness or coma. It may occur suddenly without being
preceded by any other clinical signs. The individual is usually unconscious
with a high body temperature and a hot dry skin (heat stroke victims, contrary
to popular belief, may sweat profusely).
It is believed that the above mentioned heat stress
problems can be controlled provided certain precautions are taken. According
to the American Academy of Pediatrics Committee on Sports Medicine, heat
related illnesses are all preventable. (Sports Medicine: Health Care for Young
Athletes, American Academy of Pediatrics, July 2000). The following practices
and precautions
are recommended:
1. Each
athlete should have a physical examination with a medical history when first
entering a program and an annual health history update. History of previous
heat illness and type of training activities before organized practice begins
should be included. State high school associations recommendations should be
followed.
2. It
is clear that top physical performance can only be achieved by an athlete who
is in top physical condition. Lack of physical fitness impairs the performance
of an athlete who participates in high temperatures. Coaches should know the
PHYSICAL CONDITION of their athletes and set practice schedules accordingly.
3. Along
with physical conditioning the factor of acclimatization to heat is important.
Acclimatization is the process of becoming adjusted to heat and it is essential
to provide for GRADUAL ACCLIMATION TO HOT WEATHER. It is necessary for an
athlete to exercise in the heat if he/she is to become acclimatized to it. It
is suggested that a graduated physical conditioning program be used and that
80% acclimatization can be expected to occur after the first 7-10 days. Final
stages of acclimatization to heat are marked by increased sweating and reduced
salt concentration in the sweat.
4. The
old idea that water should be withheld from athletes during workouts has NO
SCIENTIFIC FOUNDATION. The most important safeguard to the health of the
athlete is the replacement of water. Water must be on the field and readily
available to the athlete at all times. It is recommended that a minimum
10-minute water break be scheduled for every half hour of heavy exercise in the
heat. Athletes should rest in a shaded area during the break. WATER SHOULD BE
AVAILABLE IN UNLIMITED QUANTITIES.
5. Check
and be sure athletes are drinking the water. Replacement by thirst alone is
inadequate. Test the air prior to practice or game using a wet bulb, glove,
temperature index (WBGT index) which is based on the combined effects of air
temperature, relative humidity, radiant heat and air movement. The following
precautions are recommended when using the WBGT Index: (ACSM's Guidelines for
the Team Physician, 1991)
Below 64 - Unlimited activity
65-72 - Moderate risk
74-82 - High risk
82 Plus - Very high risk
6. There
is also a weather guide for activities that last 30 minutes or more (Fox and
Matthew, 1981) which involves knowing the relative humidity and air
temperature:
AIR TEMP DANGER
ZONE CRITICAL ZONE
70 F 80%
RH 100% RH
75 F 70%
RH 100% RH
80 F 50%
RH 80% RH
85 F 40%
RH 68% RH
90 F 30%
RH 55% RH
95 F 20%
RH 40% RH
100 F 10%
RH 30% RH
RH = RELATIVE HUMIDITY
One other
method of measuring the relative humidity is the use of a sling psychrometer,
which measures wet bulb temperature. The wet bulb temperature should be
measured prior to practice and the intensity and duration of practice adjusted
accordingly. Recommendations are as follows:
Under 60 F -
Safe but always observe athletes
61-65 F -
Observe players carefully
66-70 F -
Caution
71-75 F -
Shorter practice sessions and more frequent water and rest breaks
75+ F -
Danger level and extreme caution
7. Cooling
by evaporation is proportional to the area of skin exposed. In extremely hot
and humid weather reduce the amount of clothing covering the body as much as
possible. NEVER USE RUBBERIZED CLOTHING.
8. Athletes
should weigh each day before and after practice and WEIGHT CHARTS CHECKED.
Generally a 3-percent weight loss through sweating is safe and over a 3-percent
weight loss is in the danger zone. Over a 3-percent weight loss the athlete
should not be allowed to practice in hot and humid conditions. Observe the
athletes closely under all conditions. Do not allow athletes to practice until
they have adequately replaced their weight.
9. Observe
athletes carefully for signs of trouble, particularly athletes who lose
significant weight and the eager athlete who constantly competes at his/her
capacity. Some trouble signs are nausea, incoherence, fatigue, weakness,
vomiting, cramps, weak rapid pulse, visual disturbance and unsteadiness.
10. Teams
that encounter hot weather during the season, through travel or following an
unseasonably cool period, should be physically fit but will not be
environmentally fit. Coaches in this situation should follow the above
recommendations and substitute more frequently during games.
11. Know
what to do in case of such an emergency and have your emergency plans written
with copies to all your staff. Be familiar with immediate first aid practice
and prearranged procedures for obtaining medical care, including ambulance
service.
Heat Stroke: THIS IS A MEDICAL EMERGENCY-DELAY
COULD BE FATAL. Immediately cool body while waiting transfer to a hospital.
Remove clothing and place ice bags on the neck, in the axilla (armpit), and on
the groyn areas. Fan athlete and spray with cold water to enhance evaporation.
Heat Exhaustion: OBTAIN MEDICAL CARE AT
ONCE. Cool body as you would for heat stroke while waiting for transfer to a hospital.
Give fluids if athlete is able to swallow and is conscious.
Summary: The main problem associated with
exercising in hot weather is water loss through sweating. Water loss is best
replaced by allowing the athlete unrestricted access to water. Water breaks
two or three times every hour are better than one break an hour. Probably the
best method is to have water available at all times and to allow the athlete to
drink water whenever he/she needs it. Never restrict the amount of water an
athlete drinks, and be sure the athletes are drinking the water. The small
amount of salt lost in sweat is adequately replaced by salting food at meals.
Talk to your medical personnel concerning emergency treatment plans.