21 May 2015

Don't Just Sit There - Do Something

From Our Changing World, 9:20 pm on 21 May 2015

By Alison Ballance

I find it quite amazing that with just this little tiny bit of exercise that you do throughout the day, you get such significant results on your blood glucose.
Meredith Peddie, Department of Human Nutrition, University of Otago

Getting off your butt is better for your health – and doing it regularly and frequently is the key.

Just getting out of your chair and walking along the corridor, or up and down a flight of stairs.”

'Get up out of your chair and regularly walk along the corridor or up and down the stairs' - that's the advice from researchers who say spending too much time sitting is bad for our health. Photo of person walking down the stairs.

'Get up out of your chair and regularly walk along the corridor or up and down the stairs' - that's the advice from researchers who say spending too much time sitting is bad for our health. Photo: RNZ / Alison Ballance

That, in a nutshell, is what the latest evidence is showing, says post-doctoral researcher Meredith Peddie, who has already shown in her PhD research that ‘if you sit for a long time you’re less able to clear sugar out of your bloodstream effectively, but if you get up and move around you’re more effective at clearing glucose.”

Now, she’s investigating in more detail what happens to our metabolism after meals when we interrupt sedentary behaviour with different amounts of exercise. In particular she’s interested in measuring “how quickly and efficiently you clear [both] fat and sugar out of your blood stream after you’ve eaten a meal. Getting up is good for clearing sugars and we’re just trying to see if it affects lipids as well.”

“Even in people who don’t have diabetes, if you have higher levels of blood glucose your risk of developing health-related complications is higher long-term.”

Meredith says that preliminary research in this area using rats had showed that sitting resulted in a decrease in the production of an enzyme called lipoprotein lipase, which is responsible for clearing triglycerides from our blood stream. While her previous work didn’t show this she suspects that it was to do with study design, and with the speed at which humans produce lipoprotein lipase after exercise compared to the rodent model.

Meredith is currently running a study at the University of Otago in which 36 participants each come into the clinic for eight days, and take part in four different exercise strategies. The four strategies are: sitting all day with no exercise; sitting all day followed by half an hour of steady exercise; sitting interspersed with brisk walking up an incline for two minutes on a treadmill every half an hour; and walking for two minutes on a treadmill every half an hour plus 30 minutes of continuous exercise at the end of the day. Participants receive the same meals each day, have their blood parameters and oxygen regularly measured, fill out appetite questionnaires and wear accelerometers so their exercise outside the clinic can be measured as well.

One of the benefits of this cross-over study design is that each person does each of the exercise interventions so their results can be compared against themselves as well as against other people.

One of the interesting spinoffs of this research is that the researchers themselves, including Meredith as well as Master’s student Stephen Fenemor, have made themselves make-shift standing desks to work at.

After spending most of your time reading about how bad sitting down is for your health, it’s hard to stay sitting."

Study participant Kelly Brown (left) walks on the treadmill for two minutes every half hour as part of a study looking at breaking sitting time, while Meredith Peddie processes blood samples that will be analysed for sugar and fat levels.

Study participant Kelly Brown (left) walks on the treadmill for two minutes every half hour as part of a study looking at breaking sitting time, while Meredith Peddie processes blood samples that will be analysed for sugar and fat levels. Photo: RNZ / Alison Ballance

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