Ray and I try to take a walk most days but haven't walked more than 3 miles for some time.  We find it good for both the physical and mental health and lovely scenery together with good company would make it even more enjoyable. Unfortunately Ray has always been reluctant to join a walking group and close friends aren't the walking 'type' so it is uaually just the two of us.

If the walking and fresh air gave you a good nights sleep, maybe as you said you should do it more often but I'm sure cycling and swimming are just as good.