The 48-year-old — pictured officiating in Nottingham, England, last month — also reffed the touch world cups in Australia in 2015 and Malaysia in 2019.
"I think the speed and level you’ve got to continually be at, I think in four years’ time it’ll be pretty difficult."
Over seven days, Heap reffed three open-grade games a day — highlights were eventual winner Australia’s game against Lebanon, who were effectively Australia B, and beaten finalist New Zealand’s game against a fast-improving Japan — and the over-35 men’s age-group final.
He says his fitness was "really good", however the tournament was quite tiring.
"We breakfast at 6am, down to the ground and then the first game starts at 8pm and the day finishes at 6pm.
"Then you’re back at home for dinner and recovery, then rinse and repeat."
Heap says players’ skill level and pace is just increasing.
"A lot of the teams that weren’t really in contention have lifted their performance."
