Mr Poffley said being able to stay fit meant he remained mobile and delayed ending up in a wheelchair.
"If it was busy I would be the first to say I'm in the road but it's not busy at that time," Mr Poffley said.
"I think I've seen as many as six there at one time but in all my time there I've never had to wait to use the machines.
"Most men and women that work are gone by 8am. If it was busy when I go, I wouldn't bother going."
Even though he received a discounted rate, he said he still had to pay $10 a week to use the facility.
A standard adult membership for both the gym and pool is $34.23 a fortnight.
Mr Poffley said he did not think there should be any time restrictions on Seniorfit members.
"I think I should have the freedom to work out whenever I like at my age."
Bay Leisure and Events chief executive Gary Dawson said the letter had been sent after complaints.
"We are getting complaints from other members who say they are paying normal rates and these people are getting a discount. Because of this, we've had to enforce the policy that we have."
Mr Dawson said he would ask his staff to monitor gym usage in the morning. There would be a review to see whether the off-peak time should be dropped back half an hour to 8.30am.
"The Seniorfit members get an off-peak reduced rate.
"I think that's fair because it is an off-peak rate, it's not discriminatory against them because of their age."