The sedentary effect: can we ‘offset’ a day of sitting with some exercise?

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By The Gut Health Doctor Team

Dr Megan Rossi in a lab looking through a microscope

Are you finding yourself sitting more frequently? With home-working, home-schooling, nights in front of Netflix, online shopping and winter lockdown, it’s no surprise that many of us are spending more time seated than ever. But what effect is this having on our health?


It’s said that, on average, people spend around 9 hours a day sitting! 


A 2020 meta-analysis (that pooled together the results of individual studies) has found that time spent being sedentary can have a significant impact on our overall health and life expectancy.


The good news is that some ‘moderate-to-vigorous’ physical activity could reduce the risks. Here’s what you need to know…



In an ideal world, we’d all be moving every hour, but that’s not always realistic! Instead, evidence suggests the health risks related to being sedentary can be reduced by adding 30-40 minutes of moderate-to-vigorous exercise every day – so that’s a good place to start.

Morning HIIT workout before work, anyone?


The Study: What did they do?


The 2020 review combined the results from 9 studies with over 44,000 people. Their physical activity levels were tracked using accelerometers (a wearable activity monitor) for between 4 and 13.5 years. The researchers calculated how long each participant spent being sedentary (sitting, or generally inactive), and how long they exercised (at moderate to vigorous intensity) for each day.  


The Results: What did they find?


  • On average, participants spent a massive 8.5 to 10.5 hours a day being sedentary (this doesn’t count being asleep).
  • On average, participants spent between 8 and 35 minutes a day doing moderate-to-vigorous intensity physical activity.
  • When they grouped participants by their sedentary and active time, they found those who were most sedentary (>10.7 hours per day) had significantly greater health risks and reduced life expectancy. This risk was the highest for those who did the least exercise, which was maintained when researchers adjusted for other known risk factors (including smoking and pre-existing illness).
  • Those who were sedentary could significantly reduce this higher risk by doing 30-40 minutes of exercise per day.


Full disclosure

This was based on cohort studies, following people over time, and therefore there’s always a risk that some unknown variables weren’t accounted for (they did account for smoking and previous illness), which could have affected both activity levels and health risks. Also, some of the studies had relatively short follow up periods (4 years) – meaning the long-term effects and whether it can be generalised to young people are somewhat unclear.


That said, a strength of this study was the use of activity trackers, as many studies rely on participants self-reporting their own activity levels (which we all know may not be 100% true!). 


What about watching TV?


A large-scale 2016 systematic review (in the leading journal The Lancet), which included 16 studies with over 1 million people, followed up for a period of up to 18 years, suggested that those doing high levels of moderate intensity activity for 60-75 minutes a day seemed to remove the risk of high sitting time.


But when it comes to TV viewing, watching TV for 3 hours or more a day was linked with increased health risks, regardless of physical activity.


Now, it’s not all doom and gloom – but perhaps we just need to re-think those Netflix marathons and get outdoors moving our bodies a little more.


What about standing instead of sitting? 


Another systematic review and meta-analysis (again, that’s classed as one of the highest quality sources of evidence) also pulled together the results from 9 intervention studies, with 877 people in total. They looked at the effect of standing instead of sitting, on cardiovascular health (i.e. heart and blood vessel health).


In some of the studies, people were given standing desks for their office work, while in the others, participants had counselling to encourage them to stand more. With these interventions, participants spent 1.3 hours more on average standing up.


The results?

Overall, replacing sitting with more hours spent standing did result in a small reduction in blood sugar levels. But it didn’t seem to have any benefit on other cardiovascular health factors, including blood pressure, weight or blood fats.


This suggests that moving vs. just more standing time, is likely where you’ll get your biggest (health) bang for your (time) buck. So it is worth trying to fit in some activity, even if it’s low level, throughout the day – such as getting up and walking around every 30 to 60 minutes during the working day.


Being sedentary can impact your gut health too.


Exercise benefits our gut microbiota (GM, the trillions of microbes living in our gut) – and is linked to having a more diverse range of gut microbes, independent of diet. And it’s this diversity that’s linked to better overall health. This benefit relies on sustained exercise, so find something that works for you, verse one week of heavy exercise followed by 1 month off.


Feeling constipated? Inactivity can ‘slow things down’ in your gut too, thanks to the decreased stimulation of the gut muscles.


Aim to move your body regularly, getting your heart rate up for 30 minutes most days. Whether it’s a power walk or playing sports, increasing your physical activity can make a big difference. Gentle exercise (e.g. walk) after a meal too can help support digestion, particularly if you feel like you’ve overdone it on the eating front.


Top tips to stay moving


  • Aim for at least 30 minutes of exercise a day. Most government guidelines recommend at least 150-300 minutes of exercise a week, particularly for those who spend long periods of time sedentary for their work.
  • Up your NEAT (non-exercise activity thermogenesis). That’s the scientific term for the energy we burn while we’re not intentionally ‘exercising’ – think climbing stairs, walking to do errands, cleaning and gardening.
  • Take your breaks. While it can be tempting to work through breaks, especially when work and life get busy, it’s super important to take regular breaks throughout the day. Not just for your physical health, but your mental health too.
  • Have regular ‘movement snacks’. These involve short bursts of activity throughout the day, so try setting a timer and aim for every couple of hours.
  • Embrace online workouts. There are so many great (and free!) workout videos available that are accessible to everyone.
  • Mix it up. If you find yourself bored with exercise, try keeping things varied with everything from brisk walking, running, dynamic yoga, online workouts, dancing, playing sports – anything that gets you out of breath.

Do it for your happiness too. Remember, activity positively affects your mental just as much as your physical health.


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