A maths problem, a health problem (6)
I believe the answer is:
asthma
'health problem' is the definition.
(asthma is a kind of health problem)
'a maths problem a' is the wordplay.
'problem' indicates anagramming the letters.
'maths' is an anagram of 'asthm'.
'asthm'+'a'='ASTHMA'
(Other definitions for asthma that I've seen before include "Mat has a respiratory disorder" , "Breathing problem" , "Breathing illness" , "Breathing complaint" , "Bronchial allergy" .)