Heat Acclimatization and Sport Acclimation

What is Heat Acclimatization?

Heat Acclimatization and Sport Acclimation are essential best practices for the prevention of Exertional Heat Illnesses (EHIs). Heat Acclimatization is a complex series of adaptive responses by the body that demonstrate improved homeostatic balance in multiple organs which generally requires days to develop adequately. Sport Acclimation is the process by which an individual learns or refreshes/refines their skills prior to full competition.


Heat-related illness has been a concern to those participating in outdoor activity for centuries. Hot, humid weather is one of the leading causes of environmental distress in athletes. Football players wearing full pads and uniforms, combined with the hot, humid weather in many regions in the late spring, summer, and early autumn, are particularly susceptible to heat-related illnesses. However, it is also important to note that athletes practicing indoors, in non-air conditioned or poorly ventilated gymnasiums are susceptible as well.


The National Athletic Trainers’ Association strongly recommends that heat acclimatization guidelines gradually phase in an increase in exercise intensity/duration and the progressive increase in the use of protective equipment in sports such as football over a period of days.

Heat Acclimatization and Sport Acclimation Policy

Summer Practices

From August 8 until September 1, there will be NO outdoor practices or activities from 11am-3pm. Practice days are Monday to Saturday only. Each player must complete 8 practice days of heat acclimatization and sport acclimation period, according to the following schedule:

  • Days 1 & 2 – Athletes may practice in t-shirt, shorts, and helmets only

  • Days 3, 4, & 5 – Athletes may practice in shoulder pads, shorts, and helmets

  • Days 6, 7, & 8 – Athletes may practice in full pads

The Athletic Trainer (HS) and/or the Head Coach (MS) will be responsible for tracking the completion of the 8 day acclimation period. The first 8 days must be single practice days and must not exceed 3 hours in length. 8 days of practice must be completed prior to participating in two-a-day practice and/or any scrimmages, and the day of the scrimmage is not included in this count. 

On Single Practice Days
  • Student athletes may not engage in more than 3 hours of on-field activities.

  • They may not engage in any other organized physical activity EXCEPT weight training.

On Multiple Practice Days
  • A total of 5 hours of on-field practice is the maximum allowed.

  • No single session practice may be longer than 3 hours in length.

  • There must be 4 hours of continuous recovery time between the end of first practice session and the beginning of the second practice session. During this 4 hour recovery period, athletes are NOT allowed to participate in meetings, or any athletic related activity, including weight training.

  • Sports medicine rehabilitation is permitted.

  • Two-a-days may only be held every other day.

Summer Scrimmages

The following rules apply from August 1 until the second Saturday in September:

  • Scrimmages can not begin after 10am and must be concluded by 12pm (noon)

  • Scrimmages can not exceed 3 hours in length

  • Afternoon games can not begin before 3pm

Hydration Monitoring
  • In an effort to monitor hydration levels and hopefully prevent heat related issues, all high school football players will be hydration tested by their athletic trainers prior to the first day of practice

  • Those who fail and are identified as being dehydrated will be retested the next day

  • If an athlete fails the hydration test twice and are deemed severely dehydrated, that athlete may be disqualified from practice that day, at the discretion of the Athletic Trainer

Temperature Readings

The DCPS/DCIAA Sports Medicine Team utilizes the Kestrel Heat Stress Meter with wet bulb globe thermometer (WBGT) to determine exposure to dangerous heat stress conditions. The Heat Index Reference Guide that is followed is:

As a general rule for all outdoor sports, the following always applies regardless of the Heat Index Guidelines.

  1. No outdoor practices between 11 AM and 3 PM.

  2. Water should be readily available during practice and/or competitions.

  3. Special Consideration should be given to students with special conditions, such as asthma, sickle cell trait/anemia, diabetes, obesity, high blood pressure, etc.

Hydration (Refractometry and Weight Charts)
  • In an effort to monitor hydration levels and hopefully prevent heat related issues, All SHS football players will be hydration tested by their athletic trainers prior to going out on the first day.

  • Those who fail and are identified as being dehydrated will be retested the next day.

  • If an athlete fails the hydration test twice and are deemed severely dehydrated, at the discretion of the Athletic Trainer, that athlete may be disqualified from practice that day. 

202-729-3288

3535 V St. NE, Washington DC 20018