With 60 per cent of us not getting enough physical activity, the last thing we need is more reasons not to exercise. Yet wrong-headed beliefs that imply exercise is too hard or harmful just create more barriers to getting fitter or put limits on what we do.
1. Running will age you faster
This one surfaced in 2011 with some cosmetic surgeons in the US and UK claiming that the pounding effect of running damages facial elasticity – and that this, together with fat loss, caused a gaunt, "runners' face". You can argue that running (or anything done outdoors) accelerates wrinkling if you don't use sun protection – but there's no evidence for facial laxity from "pounding", says Dr Adrian Lim, a spokesman for the Australasian College of Dermatologists.
"On the contrary, there are many benefits of exercise including increased length of telomeres (caps at the end of strands of DNA that protect chromosomes) that is correlated with healthy ageing and longevity," he says. "Running controls weight which is a good thing but excess weight loss from any cause such as starvation, illness or excessive exercise will lead to loss of facial fat pads resulting in a gaunt "older" appearance. But it's not exercise that's the problem – it's being abnormally underweight."
Then there's the study that compared a group of older runners aged around 69 with a group of regular walkers of the same age which found that when it came to walking, the runners walked more efficiently than the walkers, expending the same amount of energy as 20-year-olds. "The bottom line is that running keeps you younger, at least in terms of energy efficiency," said Associate Professor Rodger Kram, a co-author of the study.
2. You need at least 20 minutes of continuous cardio exercise to benefit your heart and improve endurance
"Just 10 minutes of cardio exercise (running, jogging, cycling or walking at a pace that raises your heart rate) will provide a cardiovascular benefit – although it's best to accumulate at least three of these ten minute sessions each day", says Ballarat-based accredited exercise physiologist Abby Byrne. "You'll also get a cardiovascular benefit from High Intensity Interval Training where you alternate brief bursts of exercising at an intense pace with intervals of working out at a slower pace or rest. You can apply this kind of training to walking, swimming, jogging, cycling and group exercise classes."
3. Exercise doesn't help with weight loss
It's true that exercise alone isn't the most effective way to lose weight – but the combination of exercise with the right food and sufficient sleep is what helps keep weight off, says Byrne.
"We need to recognise that keeping weight off long term depends on a number of lifestyle changes working together – not just one thing," she says.
Regular exercise helps with weight management by helping preserve and build muscle (which in turn improves metabolism – the rate at which you burn kilojoules). It also improves problems like high blood pressure and insulin resistance that can go hand in hand with surplus fat around the middle, according to Exercise is Medicine.
4. Deep squats are bad for knees
There's no one size fits all rule. For people with good mobility in hips, ankles and knees and no knee problems, a deep squat (where thighs sink lower than a position where they're parallel with the floor) should generally be fine, says Abby Byrne, although it's best to start out with the help of a qualified trainer. "There can be advantages to deeper squats in that they make some muscles work harder, but for the majority of people exercising, there's still a benefit to working muscles by squatting at a shallower depth with thighs parallel to the floor," she says.
5. It's best to exercise in the morning
If there's an advantage to working out first thing, it's that it's done before the day can derail your plan to exercise. "Beyond that, there's a benefit to exercise at any time of the day," says Byrne. "The most important thing is to fit it in."
6. Strength training at a young age stunts growth.
There's no evidence that strength training has adverse effects on growth and development in children who strength train under qualified supervision – in fact there are likely to be benefits, according to the American College of Sports Medicine. Strength training can enhance bone density in girls, decreasing the risk of osteoporosis later on and can spark an interest in physical activity in overweight children who tend to dislike prolonged periods of exercise, says the ACSM. .
"There have been concerns about potential injury risk with children and young adolescents because we know that strength training at a high level can carry a risk of injury," adds Carly Ryan, an accredited exercise physiologist and spokeswoman for Exercise and Sports Science Australia. "But the important things is that it's done with supervision. Strength training doesn't have to mean lifting heavy weights either – it can be bodyweight exercises such as push ups or squats."
7. 'I'm older, I should slow down'
"That's old school thinking," says Byrne. "We encourage people to continue doing cardio exercise and strength training as they get older because there are so many advantages – it helps maintain mobility and independence, improves circulation, reduces the risk of chronic disease and helps you live better."