Cancer patients are being offered one-to-one exercise sessions before, during and after treatment as part of a two-year pilot scheme in North Yorkshire.
Active Against Cancer is being trialled in Harrogate and, if successful, could be rolled out across the UK.
The scheme, funded by Yorkshire Cancer Research, comes after research found physical activity is linked to better outcomes for several types of cancer.
It offers sessions with specialist trainers to everyone with a diagnosis.
Since it launched in July, more than 170 patients have been referred and that number is expected to reach 1,200 over the two-year period.
Rest and recuperation were traditionally seen as best, but now experts say exercise helps overcome the effects of the illness and its treatment.
A report by the Independent Cancer Taskforce in 2015 emphasised the importance of taking care of health through diet and exercise - both before and after diagnosis.
However, it said helping people improve their general health through exercise was not yet a standard part of cancer treatment.
Dr Kathryn Scott, Yorkshire Cancer Research chief executive, said: "Exercise plays an incredibly important role in improving cancer outcomes, from helping patients become as physically fit as possible before surgery to helping relieve side effects of chemotherapy and in some cases, helping to reduce the chance of a cancer returning.
"Through Active Against Cancer, we aim to showcase how exercise referral services can be introduced and ultimately give patients across Yorkshire the opportunity to access this vital part of cancer treatment and care."
'It couldn't be better'
Lyndsey Cooper was diagnosed with breast cancer in November and has been involved with Active Against Cancer since it launched.
She said the service had been "life-changing" and she was now "in a really good place".
"I knew I should be doing something when I was diagnosed, because I am quite a lazy person really," she said.
"I am not a gym person but this is totally different. The instructors are professional and funny, they push you but not too much, and my friends won't believe I am saying this but I love the circuits, it is actually really good fun.
"You totally forget about the diagnosis because you are having such a good time. You are getting up a sweat so you know it's doing you good.
"It is just so positive, the whole thing, and the fact that it's free and that anybody can be referred, is brilliant."