UsualSpeedUSA 4+

This is the only app that measures your daily preferred walking speed, which is important for maintaining health and youth after the age of 45.

All the people have their own "preferred walking speed", and they often walk at that speed unconsciously. You may know your own “preferred walking speed” from experience, and your body determines this speed very precisely. Therefore, if you keep walking a little faster, you will get tired quickly.
This is the only one app that measures your "preferred walking speed", and allows early detection of changes and numerical confirmation of recovery trends.
This "preferred walking speed" gradually slows down year by year. We tend to think it's because of strength in the legs, but it's also closely related to brain function. Aging weakens your sense of balance and slows down your walking speed. However, although it is an indicator of youth, simply measuring speed does not tell you what is the "preferred walking speed".
It starts to slow down actually around the age of 50. You can hardly notice the change. Recovery is easy if you notice it early and deal with it, but if you don't notice it late, recovery will be more difficult. As we age, our resilience declines.
In order to continue enjoying the era of 100-year lifespans, it is very important to stay young, that is, maintain the “preferred walking speed”.