CARDIO is a playable word

cardio Scrabble® Dictionary

noun
pl. cardios
an exercise involving the heart and blood vessels
56 Playable Words can be made from "CARDIO"
   2-Letter Words (9 found)
   3-Letter Words (22 found)
   4-Letter Words (18 found)
   5-Letter Words (6 found)
   6-Letter Words (1 found)