By: William James

It’s generally accepted that cycling is good for your you, but there are now the facts to show it. A recent study in the USA found those who exercised lived longer and had less sick days. But have you ever stopped to think just how many different body systems are benefiting from your regular rides? Here’s a list that will leave you feeling like you’ve earned yourself a karmic elephant stamp.

Your heart: Just cycling at a moderate rate makes your heart pump five times faster than at rest. And just like any other muscle, your heart will get bigger and stronger if you make it work. A Danish study conducted over 14 years with 30,000 people aged 20 to 93 years found those who didn’t ride to work had a 39 per cent higher mortality (death) rate than those who rode.

Your blood: Regular aerobic activity has been shown to reduce your blood pressure: the major risk factor in developing cardiac disease. Regular
aerobic exercise also improves levels of “good” cholesterol (HDL) in your blood.

Your brain : People who take part in regular exercise tend to have lower body fat and better blood lipid profiles than non-exercisers. This means a
reduced chance of stroke.

Your muscles and bones : Although cycling is non-weight bearing and kind to the joints, it does place enough stress on the bones of the lower body to delay osteoporosis and reduce your chances of falls and injury when you get older. It’s also been demonstrated to maintain a sense of balance.

Your lungs : Research has shown there is up to three times less exposure to pollution if riding to work by bike rather than travelling by car.

Your gastrointestinal system :Research has shown that cycling and other routine physical activities of 30 minutes a day can reduce the chance of bowel cancer and may also decrease the need for gallstone
surgery.
Your spare tyre : Last but not least, all that puffing can help you lose weight. Forget trying to search for the diet that will drop half your body weight in two weeks. It comes down to one simple equation (and I was never one for maths): to lose weight, kilojoules consumed must be less than kilojoules expended. The average diet provides between 8000 and 10,000kJ per day, which is a little more than most adults require, depending on their age, weight, height and age. When you regularly eat more energy than your body needs, the excess energy is stored as fat. One kilogram of body fat contains 37,000kJ, so to lose 1kg of body fat in a week, you would need to burn an additional 37,000kJ, about 5000kJ a day! For every kilometre of moderate cycling, a 70kg cyclist will burn 1000kJ/h cycling at 10km/h or 1700kJ/h cycling at 20km/h. That means an 8km bike ride taking about 20 minutes will burn the energy contained in a chicken and salad sandwich. A 15km ride will burn off a good-sized serving of spaghetti
bolognese, while a longer 30km ride will take care of three slices of pizza. So riding to work is a great way of burning fat but it’s not just the energy you spend on the ride. Regular exercise also increases your basal metabolism rate (BMR). An increased BMR is associated with as little as 30 to 40
minutes of exercise three to four times a week, and not only is there an increase in your overall BMR, there is an additional 12 hour post-exercise boost in the BMR. As a rule of thumb, this adds a 15 per cent kilojoule bonus to your aerobic activity. So two rides a day will have an almost permanent effect on your BMR. And finally, for those who refuse to believe in shortcuts, researchers at the University of NSW and the Garvan Institute studied 45 overweight women over 15 weeks, putting them through a 20 minute cycling regime in which they sprinted on a stationary bike for eight seconds followed by 12 seconds of cycling lightly. “They lost three times more weight than other women who exercised at a continuous, regular pace for 40 minutes,” said UNSW associate professor Steve Boutcher. It is believed this specific brand of interval training prompts the body to click into a metabolic response that allows more fat to be burned. So add a little interval work to your commute and you’ll need to get a new wardrobe.

 What you burn                                                                                Time to burn it off
INTENSITY                      SPEED                   KJ/min                         2 Weet-Bix with                                  McDonald’s 
                                                                                                          125ml skim milk (719kJ) and             Bacon and Egg Muffin (1260kj) and 
                                                                                                          skim milk coffee (337kJ)                   full cream milk coffee (627kJ)

Medium Low                    20km                     40.32                                  27min                                                47min
Medium High                     24km                    50.40                                  21min                                                38min
High >                              32km                     80.64                                  14min                                               24min