Will not get smaller. It's just that the atrophy of muscle fibers (that is, the loss of protein) makes the muscles lose elasticity and obviously relax.

For fitness people, 36 hours without exercise will start to shrink (of course not to a great extent)

For ordinary people, they will relax after a long time.

In addition, muscle will not turn into fat, but protein may turn into sugar and be consumed.

If you don't want your muscles to lose elasticity and relax and contract obviously, it is recommended to do 1 or twice a week and stick to a scientific diet.