When the hot, humid air mass camped out over the Midwest last week and then moved east to put a stranglehold on the coast, runners, group leaders, and race directors asked me many times, “When is it too hot to run?” Unfortunately, this is not a straightforward question, and the answer varies for individuals and groups. On an individual basis, we each bring to the table a set of circumstances that determine our heat tolerance, and we can make the decision to run or stay put. That decision affects only our own health, not the health and well-being of others. Knowing your limits and the factors that determine your heat tolerance will help you run safely in the heat.
From a group perspective, it is difficult to ensure that each runner brings the same factors to the start. This transfers the burden of safety to the event administration and complicates event management. The Twin Cities metro area hosted the USA CUP International Youth Soccer Tournament last week. The tournament fell right in the middle of the heat wave, and play was suspended or delayed several times during the week. The chief executive officer took the brunt of the complaints from coaches, parents, and players. His response caught my attention as he deflected the complaints with the simple statement, “I treat heat just like lightning; it is dangerous, but it will pass. My concern is the safety of the players, refs, and volunteers who may not be conditioned for this temperature and humidity.” This is a far cry from the response of 25 years ago: to essentially ignore the heat and play on.
In the road-race world, some of the most influential directors of the past would have refused to cancel a race for heat or other weather-related problems. Today, a quarter-century later, race cancellations, while not commonplace, occur when the safety of the group of runners is in question. Cancellation parameters should be developed well in advance of the race, when heads are clear and before the administrative group gets bogged down with pre-race preparations..
What factors make a difference? Again, there is no easy answer, but I consider these to be at the top of the list:
- Race history – do you know the “cut point” for your event's typical field (the point at which the number of collapsed runners begins to overwhelm the medical group)?
- Start time – early morning starts take advantage of overnight cooling and avoid the heat of the day.
- Participant acclimatization – runners who have trained for several weeks in the heat will be more tolerant of the conditions.
- Emergency medical capacity – can the community provide adequate medical coverage for the event to ensure that runners who collapse can be rapidly assessed, treated, and transferred during the peak of the race?
- Competent medical volunteers – do you have enough heat-trained volunteers to assess and manage a large number of collapsed athletes along and at the finish of the race?
- Race-course accessibility – can medical personnel easily access all areas on the course where runners might succumb to the heat?
- Adequate fluids – can the race provide the volume of fluid necessary for runners to drink when they are thirsty?
Hope this helps.