When Kate Callaghan wakes up tomorrow morning, she will enter a world of pain.
The 52-year old Taupo mother of three is one of 164 athletes competing in GODZone - a multi-day, non-stop, expedition style adventure race held annually in the South Island.
Tomorrow, Callaghan and her team Kathmandu XT
(Duncan Hamilton, Hamish Hamilton, George Christison) will begin their race through 500km of southern terrain over five days, stopping only to catch a few minutes sleep when their bodies and brains can no longer function safely.
The 41 teams of four will run, bike, kayak and walk their way around the Kaikoura District on a 'secret course' which is revealed to the athletes just before the event starts.
The leading teams will complete the journey in around four days with perhaps only one or two hours sleep throughout the duration.
But for Callaghan and her team with an average age of 51, success will be defined by making it to the finish line.
"The last race we did was the Southern Traverse in 2004, and we won," Callaghan said. So our team had this mad idea that we should all get together ten years later and give it another crack. Placing would be amazing but we have to remember, we are the oldies in the race this time."
Callaghan's team generated the $6,500 entry fee through sponsorship with Kathmandu, Vitasport, Tasti and Kaweka Meals all chipping in to support the theme of active lifestyles in the older population.
"We get issued with the map on the first morning and then we have three hours to plot the course and transitions. We won't know if we have a 12 hour trek or a 24 hour trek.
"With the food we do three hour bags and six hour bags. If we find out tomorrow it's a 24 hour trek then we throw four six hour bags into our pack and that's how it goes."
Teams are traditionally comprised of three men and a woman, with each unit only as strong as its weakest link.
"Different people have different strengths and weaknesses. For example we have a guy in our team who tends to go to sleep after 48 hours. He really struggles with sleep deprivation. I struggle with the food. The dehydrated and concentrated food, my body doesn't like that.
"We're all watching each other and making sure no one is making bad decisions - hallucinating or feeling faint. If someone says that then we literally stop, put the bikes to the side, curl up and go to sleep. Someone will always stay awake at each time and set an alarm."
For hydration her team uses snap-lock bags of liquid and camel bags that they fill up in creeks along the way.
Each team packs their bikes and Kayaks into boxes which get delivered by race organisers to the secretive transition areas.
"When we arrive at the transition, our box is there with our gear ready to go. It may sound a little sexist but even in the world of adventure racing there are still boys jobs and girls jobs. I would have no idea how to put a bike together, but I am great at packing lunches."
Callaghan predicts her team will spend just under 50 per cent of the race walking, which still leaves around 250km of mountains, oceans and coastlines to be navigated in perpetual motion.
