Obesity And Lack Of Exercise Is Literally Killing Your Brain Cells

Photo by Derek Story on Unsplash

It's time to stand up and do something about it

Our brain is susceptible to damage as a result of poor blood-glucose control. The long-term effects of poor control are associated with the accelerated death of our neurons, and dementia - notably Alzheimer's disease. Poor glucose control is more prevalent than you think, and not just in diabetics.

Poor control of blood glucose levels is not just of concern to diabetics, like me (Type 2). It's right, of course, that being a "diabetic" by definition means that you have poor control of the glucose levels in your blood.

Diabetes - a disease in which the body's ability to produce or respond to the hormone insulin is impaired, resulting in abnormal metabolism of carbohydrates and elevated levels of glucose in the blood.

Indeed, older adults with T2D are some 50% more likely to develop dementia relative to those with normal glucose metabolism.

But this is no comfort if you do not have diabetes, yet. The massive global increase in levels of obesity is a precursor to massive increases in the number of people with diabetes. There is an inevitable direct relationship between the two.

If you are currently among the current "average" population weight in almost every developed country, but particularly the US and Australia, then you are almost sure to become diabetic if you do not change your lifestyle.

This has implications for your brain health. Here's why, and what you should do about it.

Let's examine some brain facts

Our brain is only about 3% of our body mass, yet it consumes between one-quarter and one-half of the oxygen and glucose in our bloodstream! That's astounding.

That's because the neurons in our brain run at about 100 cycles per second generating electricity which powers our nervous system, and this takes an enormous amount of energy. Neurons use glucose as their primary source of energy.

Should the glucose supply be interrupted, a neuron will exhaust 80% of its available energy stores within 2 minutes. This is what happens when there is a blockage of an artery in the brain - a blood clot.

Neurons then stop functioning, and consciousness is lost. If oxygen and glucose remain low for 5 to 6 minutes, then permanent damage to the nervous system will occur.

That's the basis of the saying that we can live for 3 minutes without air, 3 days without water, and 3 weeks without food.

You may have directly experienced the sensitivity of our brain to small variations in glucose and oxygen without realising it, especially of you are over 50. Have you ever felt light-headed after bending down to get something from a low shelf, or standing up quickly? That's a result of insufficient blood reaching your brain and therefore insufficient oxygen and glucose to power our neurons. They start to shut down very quickly. (Over 50, the blood pressure sensors in our neck become less responsive and they are slower to tell our heart to pump up the blood to our head.)

None of the above is good news, but it gets worse

For diabetics, with poor blood glucose control, the level of glucose in the brain can drop without a blockage. Any low level of glucose causes the neurons to stop functioning and brings on a diabetic coma.

This coma is a life-threatening medical emergency leading to death if you are not found and helped. My neighbour died in his sleep from a diabetic coma.

And now, for the even worse news. When there is too much glucose, the brain also shuts down and puts you into a coma. 

Our neurons do this because they are critically dependant on a tightly regulated concentration of glucose and oxygen in our blood. Think of the glucose level as if it were the electricity supply to a factory. If the voltage drops too low, or rises too high, then the factory's protection circuits will shut down the supply to prevent the machinery from being damaged.

But our brain behaves differently to a factory in one crucial aspect - it tries to learn how to save itself from further damaging events. 

Here's how the scientists explain it: The increased time spent in hyperglycemia results in adaptation to inhibit blood to brain glucose transport. This adaptation works to lower central glucose concentration relative to circulating concentration; therefore, under these circumstances, it is conceivable that at a normal peripheral concentration of glucose the brain can experience hypoglycemia.

My translation: The more times you hit your brain with high glucose levels, the more defences it puts in place throughout your neurovascular system to reduce the amount of glucose circulating on your blood.

That's only a good thing if you consistently have higher than normal blood-glucose levels. In this case, our brain's reaction is helping to reduce neuron death.

But most people do not have consistently higher levels once they hit the pre-diabetic stage, and beyond, OR, if they lead a sedentary lifestyle. That's almost everyone over 30 years old, and especially those over 60. For this group  - which has poor "glycemic control" - their blood sugar levels often go out of the target range - both up and down.

Few older adults do the amount of daily exercise recommended by public health authorities, with some estimates indicating that 55% to 70% do not achieve the minimum recommended level of "moderate to vigorous physical activity".

The fact is that older adults spend very little time doing moderate to vigorous exercise and spend the majority of time in sedentary behaviour. Sedentary behaviour has been linked to poor glycemic control and increased risk of all‐cause mortality and can increase the risk of developing diabetes 11. 

You want to do all you can to avoid getting diabetes, and also to keep your blood glucose level as stable as possible to prevent cognitive decline.

Finally, some good news ... exercise regularly, lightly

Researchers found that light-intensity exercise improved blood glucose control. That is, the level of blood glucose is more likely to stay within the acceptable range if you exercise lightly, regularly.

As you now know, improved blood glucose control will minimise brain damage caused by fluctuating blood glucose levels.

So what's needed?

I'm talking here about the minimum exercise, just to get you moving each day to keep your brain healthy. This is your SIT LESS Routine, derived from a study of Type 2 diabetics:

1. For every hour that you are awake, spend 10 minutes standing, and even better if you do it throughout the whole period. Stand up and move about regularly.
2. Walk at a light intensity for 2 hours across the day. If you have a pedometer, you are aiming for about 18000 steps each day.

If this does not suit your lifestyle, then modify it using these guidelines:

1. Avoid prolonged sitting - I have a timer set for 25 minutes, and I stand up from my work desk and move about when it sounds, and every 2 hours I walk outside for 5 minutes. You might prefer to do it every time an ad comes on the TV.
2. Adjust the duration and frequency of your light physical activity, aided by timing around meals, more so than worrying about intensity. (Walking after a meal is more beneficial than walking before a meal for glucose control.)

Keep moving, and your brain will thank you, and you will live longer better.

​Good luck.

PS you can achieve additional blood glucose control by attention to your diet, in particular by avoiding high-added-sugar foods, e.g. sugar-sweetened drinks, such as soft drinks, sports drinks, energy drinks, and juice drinks, candies, cakes and cookies.

Over 50? Exercise cannot undo the damage of added sugar, unless you plan to run 52km a week

I am diabetic. I eat fruit, you should too

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