Over the last year, I have focussed on one particular Lifestyle Change, breathing properly. This is what happened in case it helps someone else:
I read from two sources (James Nestor & Patrick McKewan on YouTube) that I should breathe lightly through my nose only and when breathing in not puff out the chest but the stomach - how do you reach 67yo without breathing properly!
On my two daily walks I focus on keeping my mouth closed and breathing slowly - 5 secs in, 5 secs out and 5 secs before the next breath in. The rest of the time, I keep my mouth closed when I think of it.
At night, I use a nasal strip and a thumb nail piece of tape across the middle of my lips.
Conclusion: Increase in energy even when waking up twice for bathroom visits (normal for me for many years); previously if I woke up several times in the night I would be wiped out the next day. Haven't been retested to see if my mild sleep apnea has improved but have had no jerk awakenings in the night with rapid heartbeat and my gut feel is I should continue with this change.
I would be interested however to know anybody else's experience with similar action.