Relaxed in desert conditions (6)
I believe the answer is:
rested
'relaxed' is the definition.
(I've seen this before)
'desert conditions' is the wordplay.
'conditions' is an anagram indicator (condition can mean to influence or treat).
'desert' with letters rearranged gives 'RESTED'.
'in' acts as a link.
(Other definitions for rested that I've seen before include "Reposed or took a breather" , "Took a break from activities" , "Took one's ease" , "Relaxed, took a break" , "Took break in desert" .)