In very hot running races or triathlons, our tests have shown that running paces can be reduced by as much as 30 seconds per mile. During training tests, the runner’s heart rate is significantly reduced when running at the same pace, or, if the heart rate is kept the same in training runs in the same temperature conditions, the runner will maintain a higher pace.

For example, on two different 85°F days, a test runner ran 8 miles on the same course keeping his heart rate at 140 bpm in both runs.  The run with the ICED Cap with ice was run at about 30 seconds per mile faster than the run without ice.  Our tests have shown that running with ice in an ICED Cap lowers the effective temperature about 20°F as far as running paces are concerned.   So if a race temperature is 80°F, it will feel like it is about 60°F.  The inventor uses the ICED Cap in all races of about 70°F or higher.


Since most 5K and 10K races do not give out ice at the aid stations, it is necessary to start the race with ice in the ICED Cap. If you have a friend who is not running in the race with you at the start, take a small cooler to the start and load the cap right before the start of the race. Your friend can then take care of the cooler. If it is a large race with starting corrals, or if you don’t have a friend with you at the start, you can take a resealable bag with 2-3x as much ice as you need to the start. This is to allow for some of the ice melting while waiting. Just before the race starts, fill the ICED Cap and discard the resealable bag. For most runners, the ice will last for most or all of a 5K race. During 10K races, the ice will last for the first half of the race for most runners, and the water from the ice that drips onto the runner’s clothes will cool for the whole race.

White ICED Cap Running Boston Marathon