How low is too low?

lotuslight said:

Especially since DVLA won’t let you drive at 5 below.

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If you are on insulin or similar you cannot drive if you are less than 4, above 4 but below 5 then you must eat/drink carbs before driving

If you are not on insulin or similar you are fine at 4, 5 whatever

DVLA has no minimum BG unless you are taking something like insulin or glycazine.
If you are, the minimum to drive is 4.0 but if your levels are below 5 you should eat carbs.
7 is not low. It is the top end of the range someone without diabetes will experience.

The problem with running with low but acceptable glucose levels ie 4-5 mmol is that your body gets used to this low level and your hypo awareness although still there will likely be at a level where you are having a hypo before you realise how low you’ve become.

I’m on gliclazide and had a hypo in my sleep, luckily it woke me up but really scary.

Mike_T said:

The problem with running with low but acceptable glucose levels ie 4-5 mmol is that your body gets used to this low level and your hypo awareness although still there will likely be at a level where you are having a hypo before you realise how low you’ve become.

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I do not consider 4s and 5s as low. People without diabetes spend most of their time in this range. I prefer to do so to avoid complications but set my CGM alarm at 4.5 to correct.
After 20 years, 8 have problems with hypo awareness.

Many above have already answered the technical question, but just to add my personal experience where exercise is concerned. I'm type 2, managing my blood glucose with diet alone currently. 5 weeks in and "normal" readings for me are 6-7 mmol/L for first thing in the morning, 5.5 to 6.5 for pre-meal and post meal, on a low carb diet.

With intense exercise a couple of hours before, my next pre-meal reading has been 4.7 at it's lowest to date, so potentially be careful around exercise intensity if you're driving soon after until you get a measure of how your BG reacts to it.

Also worth adding, although I don't drink alcohol, that alcohol can lead to lower BG levels. Not a concern for driving (hopefully ), but just be aware if you do indulge and are concerned about hypos.

I wouldn’t class being in the 7s as low. If I went below 4 then I’d worry. I’m on metformin and Forxiga (dapagliflozin) which can cause hypos but so far my lowest ever has been 4.7mmol/l I’m usually in the 6s although constantly striving for 4s & 5s

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