Battery drains and turning itself off during activity

Ever since recent updates my watch has done nothing but had problems with the battery draining like crazy and turning itself off during activities. I had to reset it the other week due to it turning itself off and was stuck on the triangle. I've had this watch 4 years. It shouldn't be a problem I'm not going to buy another. Got a big race coming up and quite sick of it now. Clearly a problem with the updates. As it was working fine.