The Neptune Thermoregulation System was born out of a need in the sport of obstacle racing (OCR) so it only makes sense for it to be a “recommended gear” option for an eight hour version of a Tough Mudder.
I wrote the Guide linked below so that any obstacle racer could be prepared. However, there are specific things that can be added for those who participate in a race such as this with a Neptune Thermoregulation System because your approach will most likely be a little different. For instance, in milder temperatures you would likely skip the wetsuit altogether; instead opting for a windbreaker type jacket like the Frogg Toggs rain jacket which absorbs no water. In fact check out this video where I do a quick demo/ explanation of how it will benefit you.
It will also help to know things like the number of water obstacles because the wetter you are the faster you will cool down… especially if Arctic Enema is in the mix. In addition, the elevation change can be a big deal because climbing hills will warm you up. Hills can also shield you from the wind. High winds and flat terrain will most certainly mean a race that “feels” colder.
Another factor you have to weigh is whether or not you will be wearing a hydration pack. If so, then you might not want to load the rear Neptune heaters as you might get too hot. If you are wearing a wetsuit then I wouldn’t worry about it as much because that probably means either there are a lot of water submersions or it’s cold so the added heat won’t matter.
When you get a chance, check out this Guide to see how you need to prep for the Toughest Mudder event as well as to further see how the Neptune can be used in an OCR!