The Williams racer missed the Italian Grand Prix three weeks ago after falling ill ahead of Saturday's final practice and qualifying.
He then spent a night in intensive care after suffering respiratory failure due to post-operative anaesthetic complications.
"In terms of actually the surgery side, I’m not worried about that at all," Albon told reporters at Singapore's Marina Bay street track.
"I know that’s fully recovered. It’s more just the after-effects of being in intensive care basically and the toll that has on your body."
He added that the humidity in Singapore caused difficulties for drivers and that it was "the hardest race of the year".
"I feel that these cars are quite different, maybe not quicker, but they are physical in their own ways," he said.
"They are so stiff, it’s a different toll on your body."
The Singapore race is a night event but drivers have to cope with heat, humidity and relentless corners for up to two hours in Sunday's race.
Many of them train in saunas or with multiple layers of clothing to simulate the race's demands.
Albon said he had to build his training routine back up steadily, starting Monday last week.
"It’s quite a tricky one because you’re basically waiting for your lungs to recover," he said.
"At the same time your body can’t move as well as it normally can so you can’t just jump back into normal training, you have to slowly build into it."
Albon, who was replaced by Nyck de Vries in Monza, added he felt ready to race on Sunday but would assess his fitness following Friday practice.
"Like I said, I’m not planning to not race," said Albon.
"Truthfully I feel pretty confident in my body but of course nothing quite compares it to the actual toll of driving these cars."