Former hospital north of state capital tackling oxygen fatigue (10)
I believe the answer is:
exhaustion
'fatigue' is the definition.
(I know that exhaustion is a type of fatigue)
'former hospital north of state capital tackling oxygen' is the wordplay.
'former' becomes 'ex' (prefix meaning former or onetime).
'hospital' becomes 'H' (abbreviation for hospital).
'north of state capital' becomes 'austin' (I can't justify this - if you can you should give a lot more credence to this answer).
'tackling' means one lot of letters goes inside another (to tackle is to take possession of).
'oxygen' becomes 'O' (atomic symbol for oxygen).
'austin' placed around 'o' is 'austion'.
'ex'+'h'+'austion'='EXHAUSTION'
Can you help me to learn more?
(Another definition for exhaustion that I've seen is " fatigue".)