Battery life when hiking

I know there are a lot of discussions around battery life on a 5 Plus.  I've had mine for about 8 months now, and while I'm mostly happy with battery life day-to-day, I have a question around settings to conserve battery life.

I went on a 10 hour hike yesterday.  I started the Hiking activity and only paused it twice - accidentally.  When I started the watch was at 92%.  When I stopped the hike 10 hours later the watch was at 36%.  I have wrist-based heart rate on.  I have phone notifications off (My phone was in airplane mode anyway).  Backlight on gestures is turned off.  

What other settings can I look at to reduce battery usage?  I am planning on some upcoming multi-day 6-10 hour hikes without the ability to re-charge.  At this rate my watch won't last more than a day and half.

Thanks for any advice!