Old wives have a lot to answer for. These elderly so-called experts have been handing out advice for centuries – yet when it comes to our health, they’re very often wide of the mark.
Here are 15 ways you’ve been led astray.
Myth 1: Chewing gum sits undigested in your stomach for seven years
Gum passes unimpeded through your digestive tract in a couple of days. Chewing gum is made from gum base, sweeteners, colouring and flavouring.
Gum base is pretty indigestible: it’s a mixture of elastomers, resins, fats, emulsifiers and waxes, some of which resist your stomach’s digestive juices.
However, your gut just keeps them moving through your system until they come out the other end.
Myth 2: Cold weather causes colds
You can go out without a coat, or sprint naked directly from your shower into the Siberian winter air if you fancy – it won’t make it any more likely that you’ll catch a cold. Colds are caused by germs, not low temperatures.
One study put the virus that causes colds into subjects’ noses and then chilled some of these people. They were no more likely to be infected with a cold than those that weren’t chilly.
In another study, people who had their feet chilled reported experiencing cold symptoms, despite not having the virus.
Myth 3: Excessive hat-wearing leads to baldness
Hipsters rejoice – your trilbies won’t leave those follicles in tatters. This strange little myth can be safely ignored, unless you wear either painfully tight hats that rip the hair away, and/or hats filled with glue.
Myth 4: You lose most body heat from your head
This myth probably originates from a military study 50 years ago when subjects were put in arctic survival suits minus hats and measured for heat loss.
Since their heads were the only parts of them exposed, that’s where they lost the most heat. More recent studies in the US have proved that any part of the body exposed to the elements will lose heat.
Study that debunks this myth: https://www.theguardian.com/science/2008/dec/17/medicalresearch-humanbehaviour
Myth 5: Swimming after eating is asking for trouble
Most of us have been given similar warnings over the years but what happens if you decide to jump in the deep end right after lunch? Perhaps not the deadly cramping some people would have us believe.
Accredited practising dietitian with the Victorian Institute of Sport, Clare Wood, says after a meal the digestive system draws on the blood from around the body to help with the digestive process.
As the blood moves away from the muscles, there is less oxygen and nutrients being delivered.
This increases the chances of the muscles not functioning as efficiently as usual – which could possibly lead to the theory that swimming after eating is dangerous.
Also doing strenuous exercise with a full stomach can be uncomfortable and has been known to make people vomit.
But there’s no research to confirm the old wives tale that swimming after eating causes cramps.
So a relaxed dip in the pool or a splash in the waves after eating should be fine.
But you might want to wait a while before swimming those laps or heading in rough surf. And remember to always keep an eye out kids near the water – food or no food.
Myth 6: You can target fat loss
It’s intuitive to think that sit-ups will kick your belly fat into touch, but it’s wrong. The fat broken down during exercise comes from all over the body – you can’t just work on those love handles.
Myth 7: “Feed a cold, starve a fever”
As a human, it’s generally wise to eat, especially when your body requires the energy to fight illness of any stripe.
Myth 8: Cracking your knuckles will give you arthritis
Knuckle “cracking” has not been shown to be harmful or beneficial. More specifically, knuckle cracking does not cause arthritis. Joint “cracking” can result from a negative pressure pulling nitrogen gas temporarily into the joint, such as when knuckles are “cracked.” This is not harmful.
Myth 9: You must never start a workout without stretching
Warm up, by all means, but there’s no evidence that static stretching prevents injuries. If you’re a runner or a cyclist, it might even slow you down. (Dynamic stretching, on the other hand…)
Myth 10: Unwashed hair is unhealthy hair
Steady on with the shampoo. It’s actually squeaky-clean hair that’s crying out for help, as you’ve stripped away its natural oils to leave a dry thatch.
Myth 11: You only use 10% of your brain
People have believed for the last 100 years that humans only use a small fraction of their brains’ capacity – but they were wrong.
Brain imaging technology shows that no area of the brain is completely silent or inactive – and because each region has its own special job, you can’t afford it to be.
Myth 12: Your urine should be almost clear
Common wisdom has it that pee should be clear to pale yellow: any darker and you’re dehydrated.
It’s true that urine gets darker as you dry out, but at its typical concentration urine is moderately yellow, which is “dark” compared to the guidelines we’re used to, but it’s actually five times below what is classified as dehydration.
So normal urine from a healthy, well hydrated person may be very yellow.
Myth 13: You should drink eight glasses of water per day
The idea that we need 2.5 litres of water a day dates from 1945 and comes from the US Food and Nutrition Board.
However, it added that most of this liquid requirement could come from food, which more recent studies have backed up.
It’s also a myth that if you feel thirsty you’re already dehydrated – this can occur when the concentration of the body’s fluids rises by as little as 2%, well below the 5% level that defines dehydration.
Myth 14: Reading in the dark ruins your eyesight
The worst this will do is cause temporary eye strain. In people with disorders that cause dry eyes, reading in poor light led to decreased blinking, which resulted in reduced vision.
However, eyesight improved when they stopped, suggesting that eyes return to normal when the strain ends.