Garbage, says Dr Mansberg. This myth started in the 1940s when penicillins were first used, mainly to treat venereal diseases (aka STIs). "Doctors thought that anyone who had contracted these diseases must have done so while drunk, so as a moral precaution advised patients to stay off the plonk until they'd finished treatment - that way they wouldn't spread the STI further," she explains.


If you break a bone, doesn't it heal stronger?

Nope, says Dr John Batten, president of the Australian Orthopaedic Association. After a bone is fully recovered - which takes between six weeks and three months - it resumes the strength it had before you busted it. No more, no less. And, get this, bones are what Dr Batten calls self-optimising tissue: they become stronger as you "work them". "To run a marathon, you need to train for months to make your bones strong and avoid injury. Weight-bearing exercise makes them particularly strong," he explains. "If you don't do a lot of activity, your bones optimise only to what you expect of them. And if you don't do any weight-bearing exercise, your bones may eventually become osteoporotic." Don't ignore cardio: University of Missouri, US, researchers found that high-impact activities, such as running, might have a greater positive effect on bone density than resistance training.

Is hanging upside down bad for me?

Hanging upside down is usually safe; it may even be good for you, says Goodwin. "Being upside down allows blood and lymph, which can often pool in the legs - especially for those prone to water retention - to recirculate through the body. The brain and its major glands (pituitary, pineal, hypothalamus) are flushed with blood, improving their function." Same goes for your organs: they're more flushed with fresh blood than Dracula. But, warns Goodwin, you shouldn't go 180 if you're pregnant or obese; have a hernia, ear infection, detached retina, heart condition, hypertension or recent broken bones.

Will wearing glasses or contacts make my eyes worse?

This is a myth - there's no scientific proof that glasses can physically change an adult's eyes. If you're long-sighted (you have trouble seeing things close-up), it's because your eyeballs are literally too small. In short-sighted people (long-distance vision is tough), your peepers are too big. It's genetic: if you can inherit a big nose, you can inherit big eyeballs, says Shirley Loh, optometrist and spokesperson for the Optometrists Association of Australia. "You can get used to the blur, and if you've never had glasses you've nothing to compare it to. As soon as you don glasses and compare it to something better, you know what you've been missing," she explains. Specs simply bend light rays into focus. But if they don't worsen eyesight, why would anyone ever need a new prescription? Computers strain your eyes, says Loh. According to surveys by the American Optometrist Association, 70 to 75 per cent of computer users have vision problems.

If I drop food, is it really OK if I pick it up within five seconds?

Like Spandau Ballet's come-back, this is something you really want to believe in. Well, you can. (Sort of. ) Lydia Buchtmann, spokesperson for Food Standards Australia New Zealand, explains: "Bacteria can grow on food pretty rapidly, but if you're in the middle of cooking and you pick up a dropped ingredient, rinse it and cook it straight away, you should kill the bacteria." If it's an ingredient that's not going to be cooked, Buchtmann adds, like for a salad or dessert, bin it. In a study at the University of Illinois, US - which won its author an Ig-Nobel Prize in public health from the Annals of Improbable Research - gummy bears and cookies were left on tiles contaminated with E.coli for five seconds. They tested positive for E.coli. So, follow the five-second rule at your own risk.

Is it true that it takes more kilojoules to digest celery than is in the celery itself?

We wish. Buntic explains that celery doesn't increase the rate at which kilojoules are burnt: it's simply a very low-energy food. "We burn close to 600kJ per hour doing minimal activity such as watching TV or eating. So if you ate 1 cup of celery over half an hour, you're taking in 60kJ and burning 300kJ, which you'd be burning if you were eating nothing anyway," says Buntic. So don't be skipping the gym in favour of celery any time soon.

Is it true I should buy two pairs of running shoes and alternate them?

WH put this to Olympic triathlete Emma Snowsill. "I will alternate between up to four pairs; even if I run twice in one day, I won't wear the same pair," says Snowsill, who runs 80km a week. "The cushioning in shoes needs time to bounce back." Snowsill swears by Asics GT-2140s ($199.90, asics.com.au), which she dates and marks as A, B, C and D.

And if you're not a three-time world champion? "It's best to buy two pairs and alternate them, rather than wear one pair to death and risk injury or soreness," explains Snowsill.

Isn't S&M degrading? I can't respect myself if I let him spank me.

While it looks like the dominant person is calling the shots, it's actually the other way round, says Hellyer. "In fact, it's the submissive partner who controls the action, because they can stop it at any time. So unlike a real-life situation where the victim is at the mercy of the attacker, in sexual play the submissive player controls the situation," she explains. "Just don't forget to use a safe word in case you want to stop - something non-sexual - as 'No, no, stop' doesn't work. It could be interpreted as part of the play," adds Hellyer.

How does putting a spoon in a bottle of sparkling wine keep it good?

Um, it doesn't. There's as much truth to this one as an issue of the National Enquirer, says Gus Lander, spokesperson for the Wine Society: "I'm not sure why people do it, because it doesn't work." Sparkling wines, Lander explains, release a carbon dioxide gas when opened; this gas sits on top of the wine and helps prevent oxygen getting into the wine (oxidisation). "The more wine you take out of any wine bottle, the less time you have to drink it. Wine stoppers will keep vino good for three to four days, but no more. You can also buy half-bottles i

Can menstrual blood attract sharks?

This is right up there with "You can't get pregnant the first time you have sex". The internet rumour: sharks can detect a single, 1ml drop of blood in an Olympic-sized swimming pool containing about one megalitre (or 1000 million drops) of water.Righto. Andrew Fox, director of the Fox Shark Research Foundation, says he hears this question constantly on shark-diving expeditions. But sharks aren't especially excited by human blood. "Plus, the scent doesn't get carried very far at all; if the tide is going at one kilometre per hour, then a shark a kay away might smell the blood in an hour - and even then, the current would have to be unbroken," Fox says. "When we do expeditions, we throw a lot of burley or "chum" (bloody, minced-up tuna) into the water. That's what attracts sharks."

If you step on a cockroach, does it lay eggs?

We thought this rumour was the weirdest since "Marilyn Manson was Paul from The Wonder Years". But it's partly true, the same way a pregnant dog could go into premature labour if hit by a car. Cockroaches carry fertilised eggs in a case on their back until they can find somewhere to hide it, so the pressure of a shoe could literally squeeze them out, explains Martin Robinson, naturalist at Sydney's Australian Museum. But there's little chance the baby roaches would survive. Shame.

Should I remove my amalgam fillings before having a baby?

Mercury - a key ingredient in amalgam fillings - is about as popular as bushfire arsonists right now, having been linked to behavioural problems and Alzheimer's disease. But it may be more dangerous to rip your old fillings out than leave them in, says dentist Dr Anthony Goswell. "Some studies have shown that the mercury can leak but the amount is negligible, and to my knowledge, there's been no scientific study on the effect of amalgam fillings on an unborn baby," he says. The Australian Dental Association agrees. According to their website: "There is no evidence to suggest you or your baby will be harmed because of [amalgam fillings]", however they recommend you avoid any new dental work while pregnant or breastfeeding.

Is it true that killed-off brain cells don't regenerate?

Yes and no. The old school of thought: you are born with a full complement of brain cells that die off as you age, explains Professor Robert Vink, Chair of Neurosurgical Research at the University of Adelaide. The new: "There are pockets of the brain - such as the hippocampus, which controls memory - that can turn over nerve (brain) cells," he says. But not all areas of the noggin can regenerate cells - including the control centre - and any toxin (plonk, pills, pot) can kill off brain cells with bikie-gang-like ease. So you still have to protect against degeneration, through watching your intake of toxins, doing brain-training (eg, crosswords, sudoku) and physical exercise. "If you don't use it, you lose it," adds Professor Vink.

Is it true that switching a light on and off uses up more electricity than just leaving it on?

This was true when fluorescent lamps were first invented, according to Sustainability Victoria. Today, there is still a small surge in power when modern lights are flicked on, but it's nothing compared to energy racked up by leaving them on. "We can reduce carbon emissions (and power bills) by switching off lights and appliances when not in use," says Senator Hanson-Young. "Buy eco-friendly compact fluorescent globes (CFLs)." While CFLs may cost more, they're cheaper in the long run: they last between 6000 and 15,000 hours, compared with 1000 to 2500 hours for an incandescent bulb, reports Choice magazine.