A survey by a group of charities for Carers Week suggested 75% of those looking after a relative with health problems were unprepared for the responsibility - and four out of five felt they did not know where to seek support.
Andrew Barraclough, of the Carers Trust, said help is out there - if you know who to ask.
If you look after a parent, partner or child, you also need to look after yourself. Help is out there - but you need to know where to start.
As charities highlight a lack of support for carers, one woman who looks after her husband says help is there - but you have to ask for it.