Recreational complex has unusual line — rest cure to conserve energy! (7,6)
I believe the answer is:
leisure centre
'recreational complex' is the definition.
(I've seen this before)
'unusual line rest cure to conserve energy' is the wordplay.
'unusual' indicates an anagram.
'to conserve' is an insertion indicator.
'energy' becomes 'e' (physics symbol as in E=mc2).
'line'+'rest'+'cure'='linerestcure'
'linerestcure' anagrammed gives 'lisurecentre'.
'lisurecentre' placed around 'e' is 'LEISURE CENTRE'.
'has' acts as a link.
(Other definitions for leisure centre that I've seen before include "Recreational complex" , "Sports and recreation complex" , "where people can relax" , "Public building for sport and recreation" , "fitness club" .)