What precautions apply on hot and humid days?

Health Canada's guidance for people who are active in extreme heat includes:

• Check the outdoor temperature before you start so you can adjust the activity, and have an extreme heat plan.
• Move strenuous activity to a cooler time of day or another day, or to an air-conditioned space or a shaded spot away from heavy traffic. Otherwise increase the frequency of rest and water breaks.
• Check the Air Quality Health Index (AQHI) before heading out, since air pollution is often higher during extreme heat.
• Adults scheduling activities for children and youth should limit the intensity and duration of exercise, and a buddy system helps monitor for early signs of heat strain.
• Increase activity demands slowly over five to ten days to build heat tolerance (Health Canada technical guide for health care workers).
• Players at higher risk should have a coach, trainer or teammate watching them closely. Players with asthma should carry their inhaler.
• High humidity slows sweat evaporation and raises body temperature.