"By the time people are in their 50s, if you are a smoker and have a poor diet, particularly a high-cholesterol and high-fat diet, as well too much alcohol, it is going to impact on your sexual function.

"If your veins and arteries are blocked because of a poor diet, blood flow will not be as effective, which means men will find it more difficult to get an erection and women will find it more difficult to become aroused.

"If you are unfit, overweight or unwell, you are not going to be so interested in having sex. You just won't want to be bothered."

Body image is crucial to having a good roll in the hay, according to the Journal of Sex Research published in Dr Jackie Mills' book, Fighting Globesity. It found that the more a woman sees herself as unattractive, the more likely she is to report a decline in sexual desire.

The research found that women involved in weight-loss programmes experienced a boost in sexual desire and feelings of being attractive.

Sex is important, not only because we love it, but because it is good for us, according to Australian sexologist and author of Spicy Sex, Dr Gabrielle Morrissey.

"Physically, sex is good for your heart – literally. Lovemaking is good aerobic exercise, and the sexual response keeps your circulatory system toned and healthy.

"Sexually active people suffer fewer heart attacks. And it can also be good for your wasteline as foreplay and intercourse can burn anywhere between 150 to 550 calories."

Sex also has a positive effect on our emotional and mental states, she says.

"Sex provides a plethora of neurochemicals released at orgasm, which help make us feel good, and the sensation of touch can alleviate depression [mild, not clinical – if you suffer from depression, do not stop taking medication].

"Hormones released during the sexual arousal response act as disinhibitors, ease fears and anxieties, and increase a sense of calm and wellbeing."

Sex is a good antidote to stress, she says.

"Regular sexual expression... boosts immune cells, reduces physical and emotional stress, and helps us fight illness."

So look after yourself and aim for a lifetime of loving right into your eighth decade and beyond.