I am impressed by your walking. I do about the same. I know one thing. Walking helps peristalsis. So you will never have bowel problems/cancer etc.
Very true. I stopped playing 5 rounds of golf every week after quitting private club membership at age 75 and move to Florida. But I do regular treadmill now and try to get in 10,000 steps every day.
Without walking, constipation would have killed me long ago LOL.