Our understanding of sitting and heart disease dates back to 1953 where a study was done on bus drivers and conductors. The bus drivers sat down all day, but the conductors were standing up and walking up and down the stairs checking the passengers’ tickets. The researchers found that the drivers were 30% more likely to have a heart attack and they had them much younger and with worse outcomes than the conductors.
Since then, other studies have started to explain why. We have started to discover that excesses of a type of fatty acid known as ‘triglycerides’ can cause heart disease.
Triglycerides float around our bloodstream, particularly if we over-eat high carb meals, but the body has a solution to this. When we use our muscles in exercise (including gentle exercise like walking), our muscle activity uses an enzyme called ‘lipoprotein lipase’. Scientists nickname this enzyme the ‘triglyceride vacuum cleaner’ because it scoops up the triglycerides in its chemical reactions and therefore takes them out the bloodstream.
So, despite all the long fancy words, it’s actually quite simple. If we eat too much, the levels of triglycerides build up in our blood, but if we exercise and move, chemical reactions mop up the excess and help prevent heart disease. Wonderful!
But here’s where it gets interesting. It’s not just about how much movement we do, it’s also related to how we rest.
Researchers followed a hunter-gatherer tribe called the Hadza tribe in Africa. They found that although they are active when they are searching for food, building their homes and being social, they also rest for ten hours a day, which is even more than us Westerners! The big difference though is that their resting position is mostly sitting in a deep squat, rather than sitting on chairs.
Although they find it perfectly comfortable to sit in the squat because they do it so often, it requires much more muscle activity in the legs and core than sitting in a chair where the muscles are completely passive.
This muscle activity activates the lipoprotein lipase and scoops up the triglycerides and is one of the reasons this tribe have almost non-existent levels of heart disease.
What can we learn from this in the developed world? I appreciate it’s unlikely you are going to adopt this deep squat as your preferred resting position!
Thankfully we don’t need to, we just need some muscle activation to do the work. The simplest strategy for this is to use a standing desk or get up from sitting every 20 minutes to do some light exercise.
If you are working from home and no one can see you, you can even do a few squats or lunges (although this might look a little odd in the office, admittedly).
I sound like a bit of a broken record when I chat with my patients because I am always telling them to get up often and move around. This has wonderful benefits for your joints, but now you can think that you are helping to prevent heart disease too.
All references are taken from https://www.newscientist.com/