exercise type (7)
I believe the answer is:
aerobic
'exercise type' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for aerobic that I've seen before include "(Of exercises) related to increasing oxygen in blood" , "Involving or requiring oxygen" , "Of a process depending on oxygen" , "Exercise to improve cardiovascular health" , "Requiring free oxygen to breath" .)