I'm shrinking. I bet you are too.
As we get older, we tend to lose bone, cartilage, and muscle mass.
These losses in the spinal area cause us to shrink in height.
After age 40, an average person loses about one centimetre of height per decade.
This height shrinking does not matter much, but the loss of supporting mass that leads to it often causes problems with the back and neck.
Also, the loss of mass tends to make us weaker and more prone to injury.
I feel proud that I have maintained the same weight for decades, but I know that some of my weight has shifted from muscle and bone to fat. Sadly, our brain also shrinks as we grow older.
From age 30 to 80, a person loses on average 14-24 per cent of brain mass, depending on the area of the brain.
This shrinkage may contribute to various cognitive problems.
For instance, if you measure the balance of adults as they age, you will see a steady decline every decade, possibly a result of shrinkage in the cerebellum.
Most scary to me, out telomeres shrink as we age.
Telomeres are the caps of chromosomes.
Each time a cell divides, it loses a bit of its cap, which an enzyme builds back up - partially. Over many years, the caps get shorter and shorter until cells cannot divide any more.
At that point, death is nigh. I know about telomeres because I study what affects them.
I doubt that you want to shrink. I certainly do not.
Fortunately, there is at least one thing you can do about all the shrinking: exercise.
Exercising will strengthen your spinal column, delay cognitive losses and slow the shrinking of telomeres.
Understanding the value of exercise, I often walk to work.
I also hit the gym once a week and play a bit of basketball and tennis.
While I am in the gym lifting weights, I see lots of fit-looking young men and women.
I also see many ageing academics who know the value of exercise.
The toughest exercise I do involves high-intensity running on a playing field.
I run as fast as I can - I swear, I go as fast as the wind - for about 60 metres and then walk back.
Then I run again. Ten times I run. I look as if I am dying. But the truth is just the opposite.
John Malouff is an Associate Professor at the School of Behavioural, Cognitive and Social Sciences, University of New England.