Overnight low BGLs. A type 1 challenge.

Sometimes you think your invincible until you’re not.

This is how I felt with being able to feel a low blood sugar level before it got below 3.5 mmol/L (63 mg/dL) for the past 17 years.

I have had type 1 diabetes for 17 years and a lot of diabetics lose their ability to feel or get any symptoms of their blood glucose levels dropping the longer they are living with the disease.

I have been fortunate enough to still be able to get sign and symptoms to allow me to prevent my sugar levels dropping too low*.

To the contrary, earlier in June I had a strong two-week period of severe overnight lows. I would wake up drenched in sweat, feeling clammy and cold. I would drag myself to the kitchen like a zombie on auto pilot and generally shove as many bananas, honey, dates and peanut butter into my mouth as possible. By the time I would check my BGL it would be somewhere around the 2.0-2.5 mmol/L (36-63 mg/dL) mark, and this was when it was on its way back up and my cognitive function was returning.















Even with an additional dose of insulin after these lows to cover the ridiculous amount of carbs I had consumed, I would still wake up with a high BGL reading. Anywhere between 10-15 mmol/L (180-270 mg/dL) consistently across those two weeks. I was having overnight lows every night.


Upon waking, I would eat my usual breakfast after a correction dose and my usual bolus. Seeing my bgls trending down, I would finally eat my bowl of oatmeal and in a matter of an hour my bgl readings where shooting up again.

It would take a lot of insulin, 4 times of my usual daily dose, plus some of this given via an insulin pen injection, to get me back into range. My bgl readings looked like a ride at a theme park. Up and down then back up again, repeatedly.

I was blown away by the insulin resistance I was experiencing after having these overnight lows.

In my efforts to figure out how to prevent these highs that occupied most of my days, I realised that during my severe overnight lows, my body was releasing large amounts of glycogen to bring me back up while I was still in the state of sleep.

Not being able to measure or know how much glycogen my body was pushing out made it even harder to know how to treat the hypo when I was semi-conscious.

What I knew I had to do was prevent the lows.

With my marathon training ramping up and evening runs becoming more frequent, I knew this was impacting my overnight readings so needed to dramatically reduce my night time basals and be comfortable with going to bed with a higher BGL reading than I previously would.


I dropped my basals between 8pm – 3am by almost 50%. The night that I changed my basals my BGLs ran at 8.0 (144 mg/dL). Not the best but a lot better than a severe low.

My day post-breakfast and for the rest of the day, my bgls were a lot more stable, in range for most of the day and a lot easier corrected if they jumped up.

To get back to where I needed to be with my diabetes management and control, it took a good two weeks of stress, rollercoaster bgls and family and friends telling me to be patient to realise the cause of my fluctuating readings. I needed to look at my diabetes management objectively to see what could be the cause to find the solution.

A week after I fixed my overnight lows, my bgls were still not as stable as I would like them to be, but I am continuing to get them back into a tighter range.


And thankfully my overnight lows weren’t worse than they were.

*Severe low BGLs, if not treated, can result in loss of consciousness and seizure which requires an injection of glucagon directly into the muscle. They can also in extreme cases result in death.

Signs of low blood glucose levels:

  • Sweating
  • Shaking hands
  • Loss of concentration
  • Loss of cognitive function
  • Inability to speak properly
  • Hunger
  • Vision impairment

Foods to treat a low blood glucose level:

  • Medjool dates
  • Banana
  • Fruit juice
  • Glucose tablets or glucose gel
  • Dried fruit such as sultanas, figs, cranberries, apricots