Despite this, next month he'll be participating in his third Relay for Life, a 24-hour memorial and fundraising walk for the Cancer Society at Otaika Sports Park.
"To me personally, it is one of the most incredible experiences you can have, especially the night ceremony," he said.
"It's all celebrating the survivors and remembering those who have passed on.
"And, of course, it's raising money and awareness for the Cancer Society who do amazing work."
Relay For Life is on March 15 and 16, and involves teams walking or running around a track, with at least one team member on the track at all times during the 24 hours.
Mr Harwood is not fazed by walking long distances - in fact it's been a key part of his recovery.
"Even on the morning of my chemo I would still go for a walk afterwards.
"Eating well, taking care of fitness, going for walks has helped me cope."
He's urging people to register their teams and start their fundraising for the relay now.
"Definitely do it. Take part. Because it makes people on the outside understand what people go through, and also what the Cancer Society actually does."
To register for Relay for Life, contact 09 437 5593 or visit www.relay.org.nz