@jennyth My horse does sweat quite a bit so we are okay there haha. But I will be hosing and scraping from now on before rides until it cools down. I did that today and my horse was much happier. After every ride I always hose up to 3 times until she feels cool. I also do as many walk breaks as possible which seems to help. Thanks so much!
Is your horse sweating? If so, I second the idea to hose and scrape especially neck, chest and legs before tack up, and take walking breaks in the shade. If not sweating, please address that with supplements or Equiwinner patches- a horse which doesn't sweat normally will have extreme trouble working in the heat.
In summer when the weather is particularly hot, for example in competition when I am waiting to enter the collecting ring, I usually put a wet towel on my horse neck to keep him cool and my coach keeps a bucket of water to let him drink and wet the towel when it's not longer fresh :) I also avoid doing sessions too intense
My personal favorite way to keep a horse cool while being ridden is: i brush the horse first make sure he or she is clean and then just before putting on the saddle I shower the horse on his entire body and then I tack up like normal. It helps keep them a little bit cool but doesn't keep them cool the whole day!