What Does an A1C of 5.7 Actually Mean?

"I am a 55 yr old who weighs 120 and has a HgA1C of 5.7%. I eat a healthy diet."

5.7 is the first number in the prediabetes range. It's the bottom of that range, not the middle — you are one tenth of a point over the line.

The ranges

• Below 5.7 — normal
• 5.7 to 6.4 — prediabetes
• 6.5 and above — diabetes

Those cut-offs are clinical conventions, not cliff edges. 5.6 and 5.7 are barely different biologically; the line has to sit somewhere.

What the test actually measures

Sugar in your blood attaches to red blood cells. Those cells live about three months. A1C measures the percentage carrying attached sugar, which makes it an average of roughly your last 90 days.

That's its strength — it can't be gamed by one careful week — and its limitation. It tells you nothing about the shape of your days. Two people with identical A1Cs can have completely different glucose patterns, one steady and one spiking and crashing.

The part that surprises people at a healthy weight

You weigh 120 pounds and eat well, and your number still came back at 5.7. That combination is more common than the general conversation about blood sugar suggests.

Weight is one input. Genetics, age, sleep, stress, muscle mass, and — for women in their fifties — the drop in estrogen through menopause all affect insulin sensitivity independently. Estrogen falls, visceral fat increases even at a stable weight, and insulin resistance rises with it.

So a 5.7 at 120 pounds isn't a contradiction. It usually means the driver is something other than weight, which changes what's worth doing about it.

How much movement is realistic

The low glycemic trials found A1C improvements of a few tenths of a point. That sounds unimpressive until you're at 5.7, where two tenths is the whole distance back to normal range.

And in the UK Prospective Diabetes Study, which followed thousands of people already living with type 2 diabetes, every one-point drop in A1C was associated with 37% fewer of the small-blood-vessel complications people most fear. Modest movement compounds.

Try this week: write down your number and its date. In 90 days you'll have a second one to compare it against, and that comparison is the only one that means anything.

Education, not medical advice.