One in ten pensioners is being forced to stay in bed longer to keep warm as a result of rising fuel bills, according to a poll.
One in eight said they planned to stop using some parts of their homes in the cold weather to keep energy bills down.
More than 12,000 people over the age of 50, including almost 8,000 people who have retired, across Britain answered the survey for over-50s company Saga.
A third of people said they were heating fewer rooms in their homes and 64 per cent of people said they were having to wear extra layers of clothing as a result of rising energy costs.
One in five was planning to cut back on other spending so they could afford to heat their homes. Just over two-fifths who responded to the online poll said they would struggle more than in the past with energy bills this winter.
An overwhelming majority, 84 per cent, expressed concern about the rising cost of fuel.
Recently the so-called big six firms that dominate the energy supply market all announced above-inflation price hikes.
Paul Green, director of communications at Saga, said: “As we head into the cold winter months, spiralling fuel costs are striking fear in the hearts of some, but not all, pensioner households.
“For some, the fear could mean they won’t turn their heating on, and in so doing, risk their own health and welfare.
“Energy is essential so the government needs to do more to cut back on consumer green levies, put pressure on energy companies for fairer pricing and to develop new fuel sources linked to lowering consumer bills.”
Jane Vass, head of public policy at charity Age UK, said: “High energy prices along with poorly insulated homes are some of the factors that cause cold homes – a major cause of excess winter deaths.
“Those living in the coldest homes are three times more likely to die a preventable death than those living in warmer ones.
“Long term, we strongly believe that the only sustainable solution is investment to increase the energy efficiency of our housing stock so cold homes become a thing of the past.
“But there is action older people worried about rising prices can take now. Ofgem’s retail market review that has recently come into practice means that the energy market should be simpler to understand than before and allow people to find the right tariff for them.
“We would encourage anyone, whether they are struggling to pay their fuel bills or not, to shop around to ensure that they are receiving the best deal that they can.”
The rising cost of energy has featured high on the political agenda since Labour leader Ed Miliband’s pledge to freeze energy prices for 20 months if he wins the 2015 general election.
But Deputy Prime Minister Nick Clegg dismissed the Labour plan as a “con” which would result in price hikes before and after it was introduced.
Labour’s shadow minister for public health Luciana Berger said: “This survey shows the desperate lengths older people are going to in order to keep warm in David Cameron’s Britain.
“We have already seen a 40 per cent spike in the number of people suffering from hypothermia on this government’s watch. Ministers urgently need to act to help people struggling during the winter.
“Too many older and vulnerable people lose their lives every year due to living in homes that are too cold.”
A Department of Energy and Climate Change spokeswoman said: “The government is tackling fuel poverty and helping vulnerable households through schemes like the warm home discount which will help two million households this year, including more than one million low income pensioners who will receive £135 off their bill.”
A spokesman for Energy UK, which represents the big six suppliers, said: “No-one should have to resort to staying in bed longer or only using parts of their home to keep warm, your energy company wants to help, you just need to get in touch.”