Intensify revolutionary requirement to include exercises (6)
I believe the answer is:
deepen
'intensify' is the definition.
(I know that intensify can be written as deepen)
'revolutionary requirement to include exercises' is the wordplay.
'revolutionary' shows that the letters should be reversed in order (letters revolve around).
'requirement' becomes 'need' (synonyms).
'to include' means one lot of letters goes inside another.
'exercises' becomes 'pe' (Physical Education).
'need' enclosing 'pe' is 'nepeed'.
'nepeed' backwards is 'DEEPEN'.
(Other definitions for deepen that I've seen before include "Make or become more profound" , "make room for more water" , "Get stronger" , "Intensify" , "Dig out" .)