Many people with cancer are forced to wear coats indoors and go to bed early in order to keep warm, a charity has said.
Macmillan Cancer Support said that people undergoing cancer treatment can often feel colder due to side effects such as weight and hair loss, reduced energy levels and circulation problems.
As a result they are forced to choose between soaring energy bills or taking other steps to keep warm while in treatment or recovery.
A new poll conducted by Macmillan and npower found that one in five people diagnosed with cancer in the last two years have stayed in bed or gone to bed early to keep warm as a way to keep their energy bills down.
And 17% of those surveyed said they had worn a coat indoors to keep warm as a way to keep their heating bills as low as possible.
One in six of the 500 people polled who had cancer in the last two years said they have turned the heating off, even when they needed it on.
The poll comes as an energy provider pledged an extra £3 million to the npower Macmillan Fund which helps cancer patients with their energy bills.
"People going through cancer treatment are often at home more and also need to turn their heating up to deal with side effects such as weight and hair loss and circulation problems, all of which can make people feel colder," said Fran Woodard, executive director of policy and impact at Macmillan Cancer Support.
"In addition, chemotherapy itself can have a side effect of making people feel cold.
"This all means that their energy use goes up whilst their income may be reduced. npower's Macmillan Fund provides vital support to people undergoing cancer treatment, allowing them to focus on their health instead of their energy consumption."
:: For more information call Macmillan Cancer Support on 0808 808 0000 or visit macmillan.org.uk/keepwarm.