Ollie Jay is an Australian-Welsh academic based at the University of Sydney who is a researcher into exercise and working in hot conditions.

[1][2] Jay was the co-lead of a Lancet special series on exercise in the Heat, along with Kristie Ebi,[3] which also provides annual updates,[4] in conjunction with the Medical Journal of Australia.

[8] Jay has consulted with multiple national and international sporting organizations to assist with their policies and procedures on heat stress in athletes.

He is a consultant to the Korey Stringer Institute[9] and member of the Management Committee of the Global Heat Health Information Network (a venture of multiple bodies including the World Health Organization and World Meteorological Organization).

The Australian Open, through Professor Jay’s unit at the University of Sydney,[11][12][13] has developed a metric to measure heat stress (based on temperature, humidity and sunlight amongst other factors) which now guides the closing of the roof, suspension of play and additional breaks in play.