Thought Archive

Diabetes

Type 1 Diabetes — Managing Hypoglycaemia

30 Aug 2025

Type 1 Diabetes — Managing Hypoglycaemia

Intro

Hypoglycaemia (low blood sugar) is a common risk in T1D. Fast recognition and treatment prevent harm, and smart prevention reduces how often lows happen.

Key Points

  • Treat immediately if < 3.9 mmol/L (70 mg/dL) or if symptomatic.
  • Use the Rule of 15 (15–20 g fast carbs → recheck in 15 min).
  • Identify triggers (insulin timing/amount, exercise, alcohol, missed meals).
  • Recurrent or severe lows → adjust regimen with your diabetes team.

Recognizing a Low

  • Adrenergic: shakiness, sweating, palpitations, anxiety, hunger.
  • Neuroglycopenic: headache, blurred vision, confusion, irritability, drowsiness.
  • Severe: seizures, unconsciousness (needs help from others).

CGM trend arrows help anticipate drops; confirm with finger-stick if readings don’t match how you feel.

Immediate Treatment — Rule of 15

  1. Take 15–20 g fast-acting carbs
    • e.g., 4 glucose tabs (≈16 g), 150–200 ml juice, glucose gel.
  2. Recheck in 15 minutes.
  3. If still < 3.9 mmol/L (70 mg/dL), repeat step 1.
  4. If the next meal is >1 hour away, add a slow carb (toast, crackers).

Avoid chocolate or high-fat foods for the initial correction—they act too slowly.

Severe Hypoglycaemia

  • If unconscious or unable to swallow: a trained person should give glucagon
    • Nasal (spray) or injectable per device instructions.
  • Call emergency services.
  • Place on side (recovery position) once breathing is safe.

Common Triggers & Fixes

  • Too much bolus / wrong timing: review insulin-to-carb ratio and pre-meal timing.
  • Basal set too high: look for patterns at the same time daily → discuss basal reduction.
  • Exercise (during/after): reduce bolus/basal around activity; carry fast carbs.
  • Alcohol: eat with drinks; check before bed and overnight.
  • Missed/low-carb meals: match bolus to actual carbs; consider smaller correction doses.

Prevention Strategies

  • Set CGM low alerts (and predictive alerts) appropriately; consider higher overnight thresholds if prone to nocturnal lows.
  • Use temp basal reductions on pumps for planned activity; with MDI, reduce bolus or add carbs.
  • Rotate injection/infusion sites to avoid unpredictable absorption.
  • Keep hypo kit (glucose + glucagon) accessible at home, work, school, and during exercise.

After a Low

  • Note the time, activity, insulin, and food leading up to it.
  • If two or more lows occur in a week—or any severe episode—contact your team to reassess doses.
  • Consider brief target adjustments (slightly higher) after clusters of lows.

FAQ

Do I need to eat after I’m back above 3.9 mmol/L?
If your next meal is far away, add a slow carb to prevent another dip.

My CGM says I’m low but I feel fine.
Confirm with a finger-stick; treat if confirmed or if trend arrows show a fast drop.

Why do I get lows overnight?
Common reasons: too much basal, evening exercise, or alcohol. Adjust plan and consider higher overnight alerts.

Further Reading