Thoroughbreds and tennis players
 

Are throughbreds like tennis players when the temperature exceeds 39 degrees ?
I know that I would not like to play any vigorous sport in this Melbourne heat so how can one possibly expect selections to run as reliably as they would if the temperature was only 32 deg ?
Has anyone stats on 39deg temp or higher related performances ? or should one simply keep their hands in their pockets.
Your thoughts would be most welcome

All bold font = shouting. Please avoid. Moderator.

Yes, most horses like humans don't like extremely hot temperatures. If you read stewards reports, they reveal which horses suffer generally from heat stress.

Humidity affects horses more than temp. as it inhibits a horse's ability to stabilize it's body temperature which is done mostly by sweating [75%]. Pre-race anxiety and perspiration (washing out) before a race will affect nervous horses far more than calm ones and often leads to electrolyte imbalances leading to all sorts of muscle and breathing problems during a race.

For me, I'll be ignoring 2 or 3yr. old races over the next few days!