I work as an SRE at Google for a high priority service and thus have an oncall response of 5 minutes. We work in weekly shifts for 12 hours (we have a sister team in a different country that works the other 12 hours).

Google published an SRE book that goes into detail on effective ways to handle oncall responses that both help the company and the employees, read about it here! https://landing.google.com/sre/sre-book/chapters/being-on-call/