"Exercises make me exhausted" - the answer, ultimately, is a step-counter (9)
I believe the answer is:
pedometer
'counter' is the definition.
(I have seen 'Counter of paces ' mean 'pedometer' so perhaps 'counter' could also mean 'pedometer')
'exercises make me exhausted the answer ultimately' is the wordplay.
'exercises' becomes 'pe' (Physical Education class).
'make me' becomes 'dome' (I can't explain this - if you can you should give a lot more credence to this answer).
'exhausted' suggests removing the centre (the word is emptied out or exhausted).
'ultimately' indicates one should take the final letters.
'the' with its middle removed is 'te'.
The final letter of 'answer' is 'r'.
'pe'+'dome'+'te'+'r'='PEDOMETER'
'is a step' acts as a link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for pedometer that I've seen before include "It records steps taken" , "Check on walker" , "Instrument for recording the number of steps" , "Counter of paces" , "Walkers' measuring device" .)