Learning your own diabetes

Readings are information not grades

A number tells you where your glucose is and roughly what to do next. It is not a verdict on you.

Written by Updated 15 July 2025 5 min read
The 60-second answer

A number on your meter or your sensor is not a verdict on you. It tells you where your glucose is right now, and roughly what to do next, and that’s all it’s for.

  • A high or a low reading is data, not a mark out of ten: it points you towards a decision, it doesn’t say you passed or failed.
  • Glucose moves for dozens of reasons, so any single number is a snapshot of that moment, not a judgement on your whole day.
  • Time in range (how much of the day you spend roughly between 3.9 and 10 mmol/L) is a pattern over days, and patterns are what actually tell you something.
  • You can’t get “better” or “worse” at diabetes by looking at one reading harder. What helps is looking at what happened around it.
  • If checking has started to feel like being marked, that’s worth naming, because the fear of the number is its own problem.
The point of it

What a reading is actually for

A glucose reading answers one question: where am I now, and does that need action? If you’re 3.5 mmol/L, you treat a low. If you’re 14 mmol/L, you might correct or check for ketones. If you’re sitting comfortably in range, you carry on. That’s the whole job of the number.

It doesn’t answer “am I doing this right?” It can’t. It doesn’t know you skipped breakfast, walked to the station, sat in a stressful meeting, or that your insulin was a day old in the heat. It only knows the glucose at that second. Treating it as a report card asks it to carry meaning it doesn’t hold, and that’s where the dread comes from.

Snapshot vs pattern

Why one number on its own tells you very little

Glucose is never still. It rises and falls with food, insulin timing, movement, stress, hormones, illness, sleep and the weather, and most of those overlap at once. So two identical readings on two different days can mean completely different things: one on the way down after exercise (a low can come on during it or straight after, and hours later including overnight), one on the way up after a meal.

This is why a single figure can’t be graded. A 12 mmol/L that you already know about and are correcting is a different situation from a 12 you didn’t expect. The number is the start of a question, not the answer. What was happening around it, and which way it was heading, is where the useful information sits.

What to look at instead

Patterns are the thing worth reading

If you want information you can act on, look across several days, not at one point. Do you tend to run high mid-morning? Drop overnight? Spike after the same lunch every time? Those repeats are patterns, and patterns are something you and your team can actually change, by adjusting timing or doses.

Time in range and HbA1c (a blood test giving an average over roughly three months) are both pattern measures, not single-moment ones, which is exactly why they’re more useful than any one reading and also why neither is a grade. They describe a stretch of time so you can spot what’s repeating. Even then, the number that matters is “what pattern is this showing”, not “what did I score”.

What varies

What changes the number that has nothing to do with you 'trying'

All of these move glucose, and several are usually happening together. A reading you didn’t expect is far more often one of these than anything you got “wrong”. That’s not an excuse, it’s just how the biology works: the number is a sum of everything acting on you at once, so it can’t be pinned on one choice.

a meal a couple of hours agoa walk or the stairsstress or a rough nightillness or infectionhormones and time of dayheat and dodgy insulina sensor warming up or pressed on
Real-life examples

The same number, different meanings

Examples, not instructions or doses.

A 9 mmol/L after breakfast

You’ve eaten and taken your insulin, and an hour or two later you’re at 9 mmol/L. That’s food working its way through while insulin catches up. Heading back down is the expected shape, not a mistake.

A 9 mmol/L after a hypo

You treated a low, and now you’re at 9 mmol/L. Same figure, completely different story: this one is glucose recovering. Grading it as 'too high' would be reading the number with no context.

A cluster of morning highs

Looking back over a week, you’re regularly high before lunch. One reading told you nothing. The repeat is the useful bit, and it’s a concrete thing to bring to your team.

A number you dread checking

You put off scanning because you’re braced for it to be 'bad'. That reaction is worth noticing on its own. The number can’t judge you, but the fear of it can quietly stop you looking at all.

What to notice

Worth paying attention to

If you find yourself avoiding checking because you dread the number, that avoidance matters more than any single reading, and it is worth telling your team.
A one-off unexpected number rarely needs a big response. A pattern of the same thing at the same time does.
Treating a low (glucose under about 4 mmol/L) is routine: fast sugar, wait, recheck. It is not a mark against you.
Coming back to checking after weeks or months away is normal. You are not starting from zero, and there is nothing to make up for.
What to ask your team

Questions that make an appointment useful

"Can we look at my patterns together rather than one-off readings, so I can see what actually repeats?"
"Which stretch of the day should I focus on first if I want to change something?"
"What time in range figure makes sense for me, given my life right now?"
"I’ve been avoiding checking because the numbers stress me out. Can we talk about that?"
"If a reading surprises me, when does it actually need action and when can I just note it?"
Sources