The human body is built to stand, walk and run, not sit. But many of us work in jobs that require us to sit for many hours a day and then we’ll often spend our leisure time sitting too. Unfortunately our sedentary lifestyle is contributing to health problems and even shortened lifespans.
Being sedentary means sitting or lying (excluding while sleeping) for long periods. Even a person who meets the recommended physical activity guidelines can still be sedentary because they spend large periods off their feet. Only 45% of Australian adults met the physical activity guidelines in 2017-18. A staggering 70% of adults are sedentary or engage in low levels of physical activity.
Research shows there are many health risks to being sedentary, many of them chronic.
Being overweight or obese is often the first side effect people think about with sedentary behaviour. Researchers have found excessive screen time to be a contributing factor in being overweight. The excess weight of sedentary people increases their risk of chronic health problems, including cardiovascular disease, diabetes and cancer.
A 6.6 year study of 8,800 Australian adults revealed those who watched television for over four hours per day had an 80% higher risk of Cardiovascular disease mortality than those who watched less than two hours per day.
Two meta analyses in 2014 made links between sedentary behaviour and an increased risk of developing lung, uterine and colon cancer in. In the same report, there showed some inconsistencies with results for breast cancer. Another study found premenopausal women who had worked in sedentary occupations for 18 or more years had an increased risk of developing breast cancer.
It’s estimated that 7% of Type 2 diabetes cases are caused by a sedentary lifestyle. An analysis of 10 studies suggests there is a 112% greater risk of Type 2 diabetes associated with a large duration of sedentary behaviour.
Too much sitting can lead to metabolic syndrome which can include obesity, high blood pressure, high triglycerides, insulin resistance and low HDL cholesterol levels.
Researchers have concentrated on the link between sedentary behaviour and physical health more than mental health. But limited research is showing people with sedentary lifestyles have higher incidences of poor mental health. The World Health Organization’s Study on Global Ageing and Adult Health showed people with depression spent 25 minutes more per day in sedentary behaviour than non-depressed people.
So what are the physical effects of too much sitting on the body? Sitting and lying for too many hours a day takes its toll on most parts of the human body.
The largest muscle in the human body is the gluteus maximus, located behind the hip. We need the gluteus and leg muscles for walking, running and balance. Spending too much time off our feet causes the leg and gluteal muscles to weaken, which can lead to injuries and falls later in life.
Sitting causes blood to pool in the legs and can lead to varicose veins and spider veins. Most adults are aware of the link between long aeroplane flights and the risk of Deep Vein Thrombosis (DVT), but not everyone realises that sitting in a chair or lying on the lounge for hours can also cause blood clots to form in the leg veins.
Long periods of sitting causes the hip flexor muscle to shorten, which can cause pain in the hip joints. Sitting with poor posture causes compression and early degeneration of the discs in the back.
Sitting can cause irritation to some people's digestive problems. Sitting after a meal means your muscles aren’t helping as much with digestion, so your body is more likely to retain fats and sugars which cause increased weight gain.
According to doctors, sitting six to eight hours per day is likely to be bad for your health. Some people sit for that length of time at work and then spend additional hours every day sitting while driving or taking public transport, watching TV, reading their phone and socialising.
It’s no wonder more of us are leading sedentary lifestyles compared to our forebears. Changes in the type of work are largely to blame. Sedentary lifestyle jobs have increased 83% since 1950 and physically active jobs now account for 25% of the workforce, a drop of 50% since 1950.
An analysis of 13 studies found that people who sat for over eight hours per day with no physical activity had a risk of dying that is similar to the risk of dying through smoking or obesity.
There are plenty of ways to reduce the time you spend sitting each day – remember every bit counts.