The health of about half of carers is affected by the stress of their responsibilities, a report has suggested.
A quarter either have interrupted sleep or find it difficult to get to sleep, while nearly one-third suffer with stress.
Just over one in five admit they are irritable or short-tempered as a result of the demands of caring for a loved one or friend, while one in three are left feeling tired.
About one in four believe their relationships, social life and leisure time have been damaged by caring, while almost a third do not have the energy to go out and a quarter can not manage to go on holiday.
Some 60% of people think the amount of time they spend caring will rise over the next five years, according to the study from the NHS Information Centre.
More than 2,400 carers in England were questioned for the study, from an estimated five million.
While four out of five people surveyed say their quality of life is good, this fell among those spending 20 hours or more caring and those who looked after someone at home.
Just over a quarter of carers of working age say their role negatively affects their employment chances and less than 20% are aware they can request flexible working hours.
Just 11% get the carer's allowance, a maximum of £53.90 per week which is only for people caring for 35 or more hours per week. Of these, the percentage receiving the allowance rises to just under a quarter.
Around one in four have cared for the same person for at least a decade, while just under 10% had been caring for more than 20 years.