That common bedroom excuse - a headache - needs to be turned upside down, sexologist Shelley Hiestand says, because headaches can be cured by sex.
It is just one of the many health benefits derived from frequent sexual activity, says Dr Hiestand, formerly from Dunedin.
The 46-year-old Las Vegas resident has made a career out of giving doctor's orders more agreeable than most.
"I definitely encourage people to have more sex."
Dr Hiestand said those aged under 25 should aim for more than once a day and those between 25 and 30 at least once daily.
Accordingly, those between 30 and 40 should have sex at least four times a week, and anyone over 40 at least thrice weekly.
"The anti-ageing benefits are amazing. It basically doubles your life span once you get to your 60s and 70s.
"I'm 46 and my husband is almost 64. We've been married almost 20 years and make sure we have sex at least once a day." Dr Hiestand said research - including her own - showed frequent sexual activity reduced the risk of breast and prostate cancer, helped cardiovascular health and eliminated stress.
"The more sex people have, the more energetic, less depressed and more able to cope with life they are. It is the best stress relief. It helps women go through menopause easier because it balances hormone levels, and it increases libido."
She encouraged women especially to change their attitude to sex, from thinking of it as a chore to focusing on its benefits.
She studied law at the University of Otago but decided sexology was "much more interesting" and did a PhD at the Institute for Advanced Study of Human Sexuality in San Francisco.
This weekend she will be involved in the fifth Australasian Consciousness and Sexuality Conference in Auckland. Otago Daily Times