To reduce our risk of ill health from inactivity, we are advised to exercise regularly – at least 150 minutes a week – and reduce sitting time.
Studies have linked excessive sitting with being overweight and obese, type 2 diabetes, some types of cancer, and early death.
Sitting for long periods is thought to slow the metabolism, which affects the body’s ability to regulate blood sugar, blood pressure and break down body fat.
Many adults in the UK spend more than seven hours a day sitting or lying, and this typically increases with age to 10 hours or more.
This includes watching TV, using a computer, reading, doing homework, travelling by car, bus or train but does not include sleeping.
Move more, sit less
The Start Active, Stay Active report recommends breaking up long periods of sitting time with “shorter bouts of activity for just one to two minutes”.
A panel of leading experts, chaired by Professor Stuart Biddle, who reviewed the evidence on sitting for the report recommended taking “an active break from sitting every 30 minutes”.
However, there is currently not enough evidence to set a time limit on how much time people should sit each day.
Nevertheless, some countries – such as Australia, the US and Finland – have made recommendations that children limit screen time, such as TV and video games, to just one to two hours a day.
Recent research has suggested that exercising at least 60 minutes a day can offset the negative effects of sitting too much throughout the day.
London bus drivers and astronauts
The link between illness and sitting first emerged in the 1950s, when researchers found London bus drivers were twice as likely to have heart attacks as their bus conductor colleagues.
There has been an explosion of research on the ills of sitting in the past few years, prompted by our increasingly sedentary lifestyles.
It is thought excessive sitting slows the metabolism – which affects our ability to regulate blood sugar and blood pressure, and metabolise fat – and may cause weaker muscles and bones.
“Essentially, the body is ‘shutting down’ while sitting and there is little muscle activity,” says Professor Biddle.
Research on astronauts in the early 70s found life in zero gravity was linked with accelerated bone and muscle loss and ageing.
“Sitting for an extended period of time is thought to simulate, albeit to a lesser degree, the effects of weightlessness on astronauts,” says Professor Biddle.
Limitations with current research
Most of the evidence is based on observational studies, which have only shown an association between sitting and ill health but not a direct cause.
“With the current body of evidence, we don’t have a definitive answer to what’s happening,” says Professor David Dunstan of the Baker IDI Heart and Diabetes Institute, Melbourne, Australia. “We’re now expanding on what’s seen in observational research in the lab.”
The research on NASA astronauts suggests that on their return from space, even light walking was effective in overcoming the negative effects of weightlessness.
“Breaking up sitting time engages your muscles and bones, and gives all our bodily functions a boost – a bit like revving a car’s engine,” says Professor Dunstan.
Under-5s
In children under five, the advice is to limit the time they spend watching TV, travelling by car, bus or train, or being strapped into a buggy.
“There is emerging evidence that sedentary behaviour in the early years is associated with overweight and obesity, as well as lower cognitive development,” says the Start Active, Stay Active report.
While this may be a challenge for busy parents, the advice reflects growing awareness that early life experiences and habits impact upon our health as adults.
“There is a need to establish healthy patterns of behaviour during the early years in order to protect against possible health detriments in the future,” says the report.
Tips to reduce sitting time:
- reduce time spent in infant carriers, car seats or highchairs
- reduce time spent in walking aids or baby bouncers
- reduce time spent in front of the TV or other screens
Children and young people
Research suggests that children and young people in households with multiple TVs and computers tend to sit more.
For children aged 5 to 18 years, reducing sitting time includes anything that involves moving in and around the home, classroom or community.
Tips to reduce sitting time:
- consider ways for children to “earn” screen time
- agree a family limit to screen time per day
- make bedrooms a TV- and computer-free zone
- set “no screen time” rules to encourage kids to be active
- encourage participation in house chores such as setting the table or taking the bins out
- choose gifts such as a scooter, skateboard, ball or kite to encourage active play
Parents could lead by example by also reducing their TV time and other sitting-based tasks.
Adults
Tips to reduce sitting time:
- stand on the train or bus
- take the stairs and walk up escalators
- set a reminder to get up every 30 minutes
- place a laptop on a box or similar to work standing
- stand or walk around while on the phone
- take a walk break every time you take a coffee or tea break
- walk to a co-worker’s desk instead of emailing or calling
- swap some TV time for more active tasks or hobbies
Get more tips on getting active and staying healthy at work.
Older adults
Some older adults (aged 65 and over) are known to spend 10 hours or more each day sitting or lying down, making them the most sedentary population group.
“It could be partly due to reduced functionality or ill health, but there are also social norms expecting those in later years to ‘slow down’ and rest,” says Professor Biddle. “That’s not helpful.”
Older adults should aim to minimise the time they spend in extended periods of sitting each day.
“Sitting needs breaking up,” says Professor Biddle. “Long periods of TV should be avoided, and you should try to do activities that involve light movement and being ‘on your feet’ as much as possible.
“Do some tasks standing, like having coffee and chats, or even writing a letter – Ernest Hemingway wrote his novels standing.”
Tips to reduce sitting time:
- avoid long periods sat in front of a TV or computer
- stand up and move during TV advert breaks
- stand or walk while on the phone
- use the stairs as much as possible
- take up active hobbies such as gardening and DIY
- join in community-based activities, such as dance classes and walking groups
- take up active play with the grandchildren
- do most types of housework
Get more tips on getting active.
Source: NHS
