Age Concern is publishing a book to break the taboo about elderly sex

Regular sex can make them feel younger, reduces stress, boosts self-esteem and leads to better nights' sleep, it says.

And sex makes the brain release chemicals called endorphins, which act as painkillers and reduce anxiety.

Age Concern says many elderly people are reluctant to discuss sex. It is publishing a book, written by GP Dr Sarah Brewer, to help break the taboo.

When you enjoy a rewarding and regular sex life, all aspects of life, including the enormous range of benefits to your health, tend to take on a rosier hue Dr Sarah Brewer

Intimate Relations: Living and Loving in Later Life says exercise burns fat and helps prevent heart disease - but sex is the key to real health benefits and greater contentment.

Dr Brewer said: "Physical intimacy doesn't fizzle out and disappear as you get older.

"When you enjoy a rewarding and regular sex life, all aspects of life, including the enormous range of benefits to your health, tend to take on a rosier hue," she added.

Research also suggests sex prompts the release of substances that bolster the immune system.

The book offers advice on conditions such as prostate cancer and impotence, and encourages elderly people to discuss their problems with their GPs.