But he's counting on his mind "overriding the physical pain".
"I'm just lucky to have good biomechanics or something. I guess a lot of guys go fishing, but I go running. It's probably because I sit in a lab all day. I need to get out!" he says, adding that his partner supports this passion.
Botha first got the Guinness record for the fastest 100km barefoot in 11hrs, 14min 03 sec in September 2012, breaking the previous record by close to 4 mins.
The following year he bettered that record with a time of 8hrs 49mins and 42 seconds.
He now wants to shave more time off - and TV cameras will be recording this.
Meanwhile, Botha first got the "greatest distance run barefoot in 24 hours" record in October 2013. It has since been broken twice by Australian and American runners. The record now stands at 220.448km - the distance he has to beat.
Botha has been training 12-16 hours weekly, covering 120-160km. He does most of his training in shoes, but runs barefoot for the final 5km roughly of sessions "which toughens up the feet nicely".
"My feet tend to get numb and a bit more elastic with the barefoot running. But a lot of the guys who run just in shoes tend to be worse off," he reckons.
When asked why take on this weekend's mission? Botha says he wants to raise the profile of ultra-running and to inspire others to try it.
Botha says many Kiwis may not know that New Zealand has a 24 Hour Ultra-distance team of a manager, four male athletes and three female athletes which competes in World Championships and Commonwealth Championships. In 2011, they got a bronze medal in the Commonwealth 24-hour Championships in Wales. The team is preparing for the World Championships in Italy, April 2015.
