Sedentary lifestyle: health risks of sitting too much and how to move more

Sedentary behaviour means sitting or lying down for long periods. The NHS lists common examples as watching TV, using a computer, using the car for short journeys, and sitting down to read, talk or listen to music. It is different from being physically inactive, which means not doing enough activity, though the two often go together.

The NHS describes this as a modern problem. Technology has made life easier: we drive or take public transport, machines wash our clothes, we entertain ourselves in front of a screen, and many jobs involve little physical effort. People move around less and burn less energy than previous generations.

The NHS says that exercise can reduce the risk of major illnesses such as coronary heart disease, stroke, type 2 diabetes and cancer, and lower the risk of early death by up to 30%. By implication, not being active leaves people without that protection.

It also states that evidence is emerging that sedentary behaviour is bad for health, and that this kind of behaviour is thought to increase the risk of developing many long-term conditions such as heart disease, stroke and type 2 diabetes, as well as weight gain and obesity. The Department of Health and Social Care is quoted by the NHS as describing inactivity as a silent killer.

• Coronary heart disease and stroke.

• Type 2 diabetes.

• Bowel cancer, and breast cancer in women.

• Early death.

• Osteoarthritis, hip fracture and falls in older adults.

• Depression and dementia, including Alzheimer's disease.

One of the more useful points in the NHS guidance is that the two things are not the same. It says you can hit your weekly activity target and still be at risk of ill health if you spend the rest of the time sitting or lying down. A morning run does not fully offset a day at a desk followed by an evening on the sofa.

That is why the UK guidelines for adults include a separate recommendation to reduce time spent sitting or lying down and to break up long periods of not moving with some activity. The NHS does not give a specific number of hours or a break schedule in the pages used here, so the principle is simply to interrupt long spells of sitting.

For adults aged 19 to 64 the NHS says to do some type of physical activity every day. The weekly aims are at least 150 minutes of moderate intensity activity, or 75 minutes of vigorous intensity activity, spread evenly over 4 to 5 days a week or every day, along with strengthening activities that work all the major muscle groups on at least 2 days a week.

Moderate activity raises your heart rate and makes you breathe faster and feel warmer. The NHS offers a talk test: if you can still talk but not sing, you are probably working at moderate intensity. Examples include brisk walking, cycling and dancing. Vigorous activity makes you breathe hard and fast, so you cannot say more than a few words without pausing, and examples include running and swimming.

The NHS also says that if you have not exercised for some time, or have medical conditions or concerns, you should speak to your GP first and make sure your activity and its intensity are appropriate for your fitness.

The NHS says that for most people the easiest way to get moving is to make activity part of everyday life, such as walking for health or cycling instead of using the car. Any activity that raises the heart rate counts, and the more you do the better. It notes strengthening activities can include carrying heavy shopping, heavy gardening, yoga or lifting weights.

Beyond physical health, the NHS says regular activity can boost self-esteem, mood, sleep quality and energy, and reduce the risk of stress.

See your GP before starting vigorous activity if you have a medical condition, have been inactive for a long time or have concerns. Seek urgent medical help for symptoms such as chest pain or severe breathlessness during exercise. The NHS physical activity guidance is designed for most adults, including disabled adults, and also applies to pregnant women and new mothers, with some adjustments.