Oops, it doesn't look like 'exercise day' is a national day..

Other days

bow tie

Bow Tie Day
fiancee

Fiancee Day
nail polish

Nail Polish Day
gum

Gum Day
promposal

Promposal Day
boba

Boba Day
self care

Self Care Day
slime

Slime Day
tell a fairytale

Tell A Fairytale Day
believe

Believe Day