But anyone who knows Bradley's story knows he's a battler. And a bit of fatigue won't stop him.
"I've got to say, since I've been touring, going out of the country, going all over the country, what the people give me, wow, it makes me want to dig deeper. Find deeper soul to give," he says.
"A lot of people come up to me and say, 'Charles brother, I just want to thank you for opening up your heart to us, we felt it'. So it's always been like, wow."
Bradley recounts one night where he'd performed two sets and found himself backstage completely exhausted. "People wanted me to come back. But I was so drained. They started stomping on the floor, but I had no more energy to give."
He recalls one of the crew taking an ice-cold towel and wiping it on his head. "All of a sudden my energy came back. And I said 'I've got to get back out there'. I found the strength to do it.
"And the people, they just went crazy.
"If you reach that level when there's no more to give, but then you find it and you give it, the people are gonna feel it."
Bradley has become a symbol of hope and he's often approached for advice. His message is always the same. "It's never too late."
"One guy I met, he was 62, I think, and he told me, 'I thought my life was over but when I see you on that stage, you make me think there is hope for me'. I said, 'Yes there is. You got to get out there and do your thing. Let the world see who you are. Don't ever think it's too late'," Bradley says. "As long as you got the strength, you got love in your heart."
• Charles Bradley and his band Extraordinaires are at the Powerstation in Auckland on March 26.