Supermodel Cindy Crawford once revealed that she and husband Rande Gerber would often sneak off to their beachside guesthouse for some, shall we say, alone time. "Sometimes you just have to do it!" she said. She's 51, he's 53.
Many 50-somethings enjoy a healthy love life. A recent Trinity College Dublin study of 8000 adults over 50 found that 59 per cent were having regular sex, with a third of those active once or twice a week – if not more.
"I often find clients' sex lives improve vastly in their 40s and 50s," says therapist Barbara Bloomfield, author of Couples Therapy: Dramas of Love and Sex.
"Firstly, ask any 30-something parent and they'll tell you that having young children is the biggest passion-killer of all. In midlife, however, your children may well be teenagers or older, so they need you less and go out more. A lot of people report an improvement in their sex lives when their children leave home; it's a time when marriages get the va-va-voom back.
Also, divorce rates among the over- 50s are rising, says Bloomfield. "One reason older women are having a lot of good sex is because they're in a new relationship, especially if they've been unhappy in their previous one," she adds. "Women often come into their own at this age. They are confident and have fewer hang-ups. They are much more aware of their bodies and what they like and don't like – and they're not afraid to tell their partner."
Clinical psychologist Janice Hiller agrees, saying she is seeing at her practice more empowered women in midlife than ever before – in other words, women who are questioning whether they're getting everything they want out of life. "They are less willing to allow themselves to feel disregarded, undermined, neglected or ignored by their partners," she says.
Now for the bad news: sex over 50 can involve problems. Hormonal changes that take place during the perimenopause (typically from the mid-40s) can impact on libido.
Declining oestrogen levels can cause vaginal dryness and a thinning of the vaginal wall, which can make sex uncomfortable. "This is called vaginal atrophy and it can be dreadful," says Bloomfield. "I tell my clients to ask their GP for a vitamin-E cream."
Testosterone levels (important for a woman's arousal) also begin to decline, which can cause tiredness and irritability. Men can be affected by their own manopause, too. Their testosterone levels start to drop by about 1 per cent every year from 30 to 40, which can cause reduced libido, erectile problems, tiredness and poor sleep.
But much can be done to boost the libido – and the benefits of a regular sex life are numerous. According to the Trinity study, couples who continued to have sex were more positive about ageing, enjoyed better health with fewer long-term conditions and were less prone to depression. Midlife sex can also improve heart health, lower blood pressure and release the feel-good endorphin hormone, which acts as a natural painkiller.
And a study by Dr David Weeks, former head of old-age psychology at Royal Edinburgh Hospital, found that middle-aged people who had sex three times a week could look up to seven years younger than those who had sex on a less-regular basis.
"There are countless reasons to maintain your sex life," says Bloomfield. "Yet often, one half of a couple decides to give up sex, which is when resentment or boredom can creep in."
So what can you do? Part of the problem is that as women age they increasingly have what's called "reactive arousal", whereas men have "primary arousal".
"That means a man will just have to look at something he finds attractive and he'll feel aroused," explains Bloomfield. "Reactive arousal means women get aroused by being cuddled and kissed. Long kisses – around 15 seconds – are effective. I've tried this technique with quite a few of my couples [I counsel]. It's very simple but it works.
"When I see unhappy couples, I often find the thing they adored about their partner when they met has gradually become the thing they can't stand.
"The ambitious, driven partner who looked terribly attractive when you were 23 becomes the partner who is accused of being a workaholic. The life and soul of the party is fun at first, but becomes tiresome when you have responsibilities. "I tell clients that people only change a little over time and how their partner was when they met them is how they shall remain."
Janice Hiller, the psychologist, notes that she only sees unhappy couples: "The happy ones don't come to me, but I know many who are content and having great sex with their long-term partners. These couples know how to arouse each other and they know that intimacy and good communication are vitally linked. And, crucially, the stresses of childrearing have passed, so they're less tired." Sleep, it seems, is a prerequisite for good sex.
A US report recently published in the journal Menopause studied more than 93,000 women aged 50 to 79 and found that short sleep duration (fewer than five hours a night) was associated with less-satisfying sex lives.
"When you're tired, sex drive is usually the first thing to go," says nutritionist Marilyn Glenville, author of The Natural Health Bible for Women. She recommends topping up magnesium levels, known as "nature's tranquilliser" thanks to its muscle- and nerve-calming properties, which promotes better sleep.
Foods rich in magnesium include fish, green leafy vegetables and pumpkin and sunflower seeds.
Glenville also suggests improving overall health. "If you don't feel healthy, it's harder to feel energetic and sexy," she explains. She advises following a balanced diet full of "good" fats such as oily fish, eggs, nuts and seeds.
"Good fats are important for overcoming a low libido because sex hormones like testosterone are manufactured from the cholesterol contained within those foods."
Foods rich in zinc – like spinach, beef and kidney beans – are also important for the production of sex hormones. Glenville also says that getting regular exercise and managing stress can boost libido and mean you're in the mood for sex more regularly.
Which brings us on to our final, and perhaps most intriguing, question: how much sex should we be having? "There's no such thing as a normal amount," says Bloomfield. "I've had 70-year-old clients who have said to me, 'Our sex life has gone off the boil a bit lately.' And when I ask them how often they're having it, they'll say, 'Only three times a week these days.'
"I also see young, attractive 20-something couples without children who are having sex every six months or not at all.
"But, on average, I'd say once you're in your 40s and 50s, once a week to once a month is within the 'normal' range." The key to good sex in later life, according to Bloomfield, is this: "When it comes to sex, don't get old before your time. Push yourself a little bit. That's not to say you should do things you don't want to do, but keep trying new things and don't fall into the trap of just not making the effort.
"Sex in later life is like the gym – you know the benefits but often you just can't be bothered to go and there's something good on TV you'd rather watch. But when you do it, you remember how much you enjoy it and how good you feel afterwards." After all, she adds, "Sex is like a muscle – use it or lose it."