There Is a Range You Can Swing In

A checkup report prints a single number, the one measured that day. Gather several years of them and you get an average.

But suppose two people have the same average. One got a similar number every year. The other's numbers went up one year and down the next, swinging back and forth, until the average landed at that same figure.

On the report, the two look the same.

Fluctuating Itself Is Not the Problem

There are two things to ask. How much did it swing, and did it come back to where it started afterward.

The first one first. The body does not hold on to a single fixed number. It keeps adjusting within a certain range, and while that adjustment is happening the number rises and falls. A number that goes up and down means adjustment is taking place. Even in healthy people, the width of that swing differs from one measure to another.

So the fact that the number is a little different at every checkup is not, by itself, something to worry about.

But There Is a Limit to How Far It Can Return

Now the second question.

There is also a limit to how far the body can return after swinging. Move within that range and the body comes back to where it was. But swing too often, or too widely, and the force that pulls it back cannot handle all of it.

Then, even after one bout of swinging has passed, a trace remains in the body. Sometimes it remains in the nerves, sometimes in the tissue.

It is a bit like a rubber band: stretch it and let go, and it snaps back — but pull it hard and often enough, and it stays stretched.

There Are Long-Term Records

This is not just a guess.

There is a study that gathered long-term records from several countries. More than 500,000 people. All of them already had diabetes. What it looked at was not whether the number was high, but how much it differed from one measurement to the next. The one thing measured was HbA1c. And it then looked at whether heart and blood vessel problems developed years later.

People whose numbers differed a lot from one reading to the next had higher risk than those whose numbers did not.

And this held even when the average was the same. Even after matching for average, a difference remained.

But It Must Be Read Carefully

These records observed people over time; they did not deliberately swing their numbers and watch what happened. So it cannot be stated flatly that swinging widely caused the disease. People whose numbers swung a lot may also have had other circumstances involved.

And what was measured here is the difference between values measured over months and years. This differs, in both method and timespan, from ups and downs within a single day. The two should not be read as the same story.

What Still Remains

A normal average does not mean the past several years were smooth.

A single report shows the number from that day. Line up several years of them, and something else becomes visible: how widely, and how often, the numbers rose and fell.

So when I look at a report, I do not look only at this one number. I lay it alongside the past numbers. Two people arriving at the same figure are not the same if one got there on a steady line and the other got there through a wide swing.

What Narrows the Range

This connects to the discussion of a time coming when things are not like before.

When there is ample capacity to absorb, what comes in passes through gently. When muscle declines, digestion is not what it used to be, and meal intervals become irregular, the same input produces a wider swing.

If the range within which the body can return has itself narrowed, even a swing that would once have passed without notice can now exceed it.

When Testing Comes First

If a number suddenly changed by a large amount, if your weight has dropped noticeably, or if the swings have grown larger while you are on medication, this discussion does not come first for you. The measurement itself needs to be checked again first.

And if you are taking blood sugar or blood pressure medication, what is being discussed here is the size of the swing, not a suggestion to adjust your medication. Medication is something to discuss with the doctor who prescribed it.

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Fluctuating by itself does not decide whether something is good or bad. Swinging within the range the body can return from means the body is at work.

What decides it comes after that. Swing too often, or too widely, and the force that pulls it back cannot handle all of it, and a trace remains where it passed.

So what to look at on the report is not only which box a single number falls into. What shape the past several years took is part of it too. And that is where something you can act on now is found.

Written by Dr. Heo Ji-young (PhD in Korean Medicine Pathology, Kyung Hee University · former Research Professor of Herbology, Kyung Hee University)