the recommendation to walk 10,000 steps daily is a truly arbitrary one? For the figure 10,000 is based on a marketing gimmick in Japan in the 1960s - and the fact that there is a kanji sign for the number 10,000 in the Japanese language.
The advertisement you see here admonishes people with the slogan “Let’s walk 10,000 steps a day!”
一日一万歩あるきましょ
Ichi-nichi ichi-man po arukimashou!
So the device was neatly called a Manpokei - 万歩計. From man (万/10,000) + po (歩/steps) + kei (計/meter/device), i.e. 10,000 steps meter. And ever since then that figure has remained the one to target.
It might be more beneficial to walk a few steps beyond that figure though. Perhaps 12345 could be a better figure and target for increasing health.