Amazfit Watch faces

I did not find any notice ( in the manual) about influence using second hand ( on the watch display) on the power consumption. But the reality is very different. If I switch the second hand off, the life time ( without continue heart measuring ) will reach nearly 7,5 days !!!
( some notifications and alarms ). It is logical, because the watch will not changing display every second, but 60 times less - every minutes.