Eli5 – Why does music come in bars of four instead of 5/10?

Question

Recently I’ve been attending a lot of gym classes and the counts are always 4, 8, 16 etc. It made me wonder why music is set out this way and not in 5’s and 10’s like I would expect. Or am I missing something obvious?

In: 23

Answer 1

I’ve been waiting for metricized music notation for many years. All that fractional stuff is obsolete. /s