Getting soaked with ice cold water halfway through hot humid race?

That’s thermodynamic doping

I have and it did really help. I also put ice on my legs before and drank an icy drink (to cool down from inside). Tried to put ice in my cap but that didn’t work. Ended up throwing the cap. Some people are fine in heat, others just don’t cope well.

Here in the UK we are not heat adapted at all so the odd hot race will throw some people really off.

of course it helps. you can take it one step further and wear an ice thing around your neck, not sure what they're called.

but for 5ks it's not that important. more so for full marathons and above. for the 5ks, put some ice on your veins whilst youre standing on the start line waiting for the gun.

Where is this? 83/95" implies an 83 dew point.

Guessing somewhere around New Orleans. Dew points this morning look like they are 80F, 83F/95% RH is an 81.4F dew point. New Orleans is running just a bit hotter though, 87F air so RH around 80%. No matter what absolutely crazy hard to run in.

Yes, the ice water will help.

Also, maybe scale the effort back 5% to avoid severe effects. Is there money on the line for this race or just bragging rights?

I stopped running my local July 4th 5K race for this very reason. It’s at midnight in FL, but it’s still always at least 78 degrees and 75-78 dew point

No reason to go out and pay $50 to run a minute plus slower than I would in good conditions. I would do it as more of a fun run with friends and family, but none of my friends and family find that kind of thing to be fun.

It's 4 miles and just 83 degrees. You will survive.

Risky: thermal shock!

Dumping ice cold water all over yourself during a race isn't the best idea. The cold water causes your pores to contract, which can affect your ability to sweat. A better strategy is to target spot on your body where there is the most blood circulation for cooling. Limiting ice water to your head and neck is better than a full body dump.

But the best strategy for racing in the heat is pre-race cooling. Ice vests make a huge difference. They cost about $70. A 5k is short enough that you really cannot do much during the race to affect your body temp. Proper pacing goes much further than trying to cool down mid race. A high heat race will be at least 30 seconds slower than during a cool morning. If you are north of 18 min for 5k, the difference will be closer to 60 seconds. First mile should be very comfortable and feel closer to a 10k pace. You should only start feeling like you are working hard after the half way mark. Last mile will be hell, but with proper pacing your splits should be even instead of the last mile being 20-30 seconds slower than the first, which is very common among runners who do not pace properly during hot races.

Research something called the "palmar cooling method." It's where you palm ice cubes in your hand for 30 seconds to one minute (duration is important) during a race. Research suggests this method is very effective for aiding performance during hot weather events.

Alberto Salazar may be available to hand you ice hats through the race.

Absolutely: nervous system massive shock and performance boost! Yes, do it!

Seriously!

When I moved out to Arizona from the Midwest, I continued to volunteer at road races. The race directors insisted that each water container out on the course at the aid stations, should have a block of ice in them.

I had never heard of that before and had volunteered many years back home.

But, they insisted. I wouldn’t think any runner would like ice cold water dumped over his head.

Drinking cold water and putting it on thin skin near blood would probably help.

under the arm on the upper chest/side and the underside of forearms have lots of blood under thin skin for transferring the heat.

Ice packs on the sides of the chest would not add rotational weight and I bet would cool lots.