Healthy activity (8)
I believe the answer is:
exercise
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">healthy activity</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for exercise that I've seen before include "written school task" , "worry" , "Practice piece of work" , "Use" , "Exertion to develop endurance or skill" .)