You’ve probably heard that a sedentary lifestyle sat at a desk, behind a wheel or in front of the TV is seriously hazardous to your health. Maybe you googled it, heard it on the radio, or caught it on the 10 o’clock news. You possibly even know some specifics about percentage risk increases for heart disease, cancer, diabetes and even depression. But, as a runner, you’re probably sitting fairly comfortably – feeling immune from the modern-day health epidemic experts have gone as far as to christen ‘sitting disease’.
As runners, surely we needn’t stress about the dangers of sedentary living? Well, not so fast. Growing research shows that people who spend many hours of the day glued to their seats die earlier than those who sit less. Even if those sitters exercise.
‘Until very recently, if you exercised for 60 minutes or more a day, you were considered physically active, case closed,’says Travis Saunders, an exercise physiologist at the Healthy Active Living and Obesity Research Group at Children’s Hospital of Eastern Ontario, Canada. ‘Now a consistent body of emerging research suggests it is entirely possible to meet current physical activity guidelines while still being incredibly sedentary, and that sitting increases your risk of death and disease, even if you are getting plenty of physical activity. It’s a bit like smoking. Smoking is bad for you even if you get lots of exercise. So is sitting too much.’
Unfortunately, it seems that outside of regularly scheduled exercise sessions, active people sit just as much as their couch-potato peers do. In a 2012 study published in the International Journal of Behavioral Nutrition and Physical Activity, researchers reported that people spent an average of 64 hours a week sitting, whether or not they exercised the recommended 150 minutes a week. That’s more than nine hours a day of sitting, no matter how active they otherwise were.
‘We were very surprised that even the highest level of exercise did not lead to a reduced time spent sitting,’ says study author Professor Marc Hamilton. In fact, regular exercisers may actually make less effort to move outside their designated workout time. Research this year from Illinois State University, US, found that people are about 30 per cent less active overall on days when they exercise versus days they don’t hit the road or the gym. Maybe they think they’ve worked out enough for one day. But experts say most people simply aren’t running, walking or even just standing enough to counteract all the harm that results from sitting for eight or nine – or even 10 – hours aday.
Spuds on the Run
Unless you have a job that keeps you moving, most of your non-running time is probably spent sitting. And that makes you an ‘active couch potato’ – a term coined by Australian researcher Dr Genevieve Healy of the University of Queensland to describe exercisers who sit for most of their day. If they aren’t careful, she says, active couch potatoes face the same health risks as their completely inactive counterparts.
‘Your body is designed to move,’ says Hamilton.‘Sitting for an extended period causes your body to shut down at the metabolic level.’ When your muscles, especially certain leg muscles, are immobile, your circulation slows. So you use less blood sugar and burn less fat, which increases your risk of heart disease and diabetes.
One study of 3,757 women found that for every two hours they sat in a given work day, their risk for developing diabetes went up by seven per cent, meaning their risk is 56 per cent higher on days they sitfor eight hours. Another study, published in the American Journal of Epidemiology reports that someone who sits for more than six hours a dayhas an 18 per cent increased risk of dying from heart disease and a 7.8 percent increased chance of dying from diabetes compared with someone who sits for three hours or less a day.
Running will of course do you an awful lot of good, says Healy, but if you spend the rest of your waking hours sitting, those health benefits depreciate. In a 12-year study of over 17,000 Canadians, researchers found that the more time people spent sitting, the earlier they died – regardless of age, bodyweight, or how much they exercised.
Adding to the mounting evidence, Hamilton recently discovered that a key gene (called lipid phosphate phosphatase-1 or LPP1) that helps prevent blood clotting and inflammation to keep your cardiovascular system healthy is significantly suppressed when you sit for a few hours. ‘The shocker was that LPP1 was not impacted by exercise if the muscles were inactive most of the day,’ Hamilton says. ‘It’s pretty scary to say that LPP1 is sensitive to sitting, but resistant to exercise.’
Heart disease and diabetes aren’t the only health hazards active couch potatoes face. The American Institute for Cancer Research now links prolonged sitting with increased risk of both breast and coloncancers. ‘Sitting time is emerging as a strong candidate for being a cancer risk factor in its own right,’ says Dr Neville Owen, head of the Behavioral Epidemiology Laboratory at Australia’s Baker IDI Heart and Diabetes Institute. ‘Emerging evidence suggests that the longer you sit, the higher your risk. It also seems that exercising won’t compensate for too much sitting.’ According to the Alberta Health Services Cancer Care in Canada, inactivity is linked to 49,000 cases of breast cancer, 43,000 cases of colon cancer, 37,200 cases of lung cancer and 30,600 cases of prostate cancer a year.
As if that weren’t enough to get you down, a 2013 survey of nearly 30,000 women found that those who sat for nine or more hours a day were more likely to be depressed than those who sat for less than six, because prolonged sitting reduces circulation, causing fewer feel-good hormones to reach your brain.
Scared out of your chair? Good. Because the remedy is as simple as standing up and taking activity breaks. Dr Stuart McGill, director of the Spine Biomechanics Laboratory at the University of Waterloo, Canada, says that interrupting your sedentary time as often as possible and making frequent posture changes is important. ‘Even breaks as short as one minute can improve your health,’ he says. Developing healthier habits will also improve your running performance, says Nikki Reiter, biomechanist with The Run S.M.A.R.T. Project. The combination of going for a run and then parking your bum for the rest of the day (or vice versa) could be a recipe for injury. ‘The static sitting position can cause certain muscles to become tight or overstretched, neither of which is good for your running,’ she says. Even if you’ve been for a really intense or long run, regular activity throughout the day will help your recovery. So stand up now: it’s good for your body and mind.
