Printable Blood Sugar Journal

Per ADA Standards of Care (2024, Diabetes Care, 47 Suppl 1): fasting 80–130 mg/dL (4.4–7.2 mmol/L); 1–2 hours postprandial <180 mg/dL (<10.0 mmol/L); HbA1c <7% for most adults. Targets vary by age, pregnancy, hypoglycemia risk, and comorbidities. Pregnancy targets are tighter per ACOG, and children's targets are set individually by their diabetes team. Always follow your endocrinologist's individualized goals — these journal entries are documentation, not diagnosis.

Common testing times are fasting (on waking), before meals, 1–2 hours after meals, bedtime, and whenever you have symptoms; testing at consistent times makes readings comparable. People on intensive insulin therapy usually test several times a day or use a CGM, while people on oral medications may test much less often. The period column (fasting/pre-meal/post-meal/bedtime) makes patterns clear. Discuss the right frequency with your endocrinologist or diabetes educator.

Pair the carbs (g) and blood sugar columns: compare pre-meal readings with readings 1–2 hours after the meal and note how much each meal raised your glucose. Over a couple of weeks this shows how you personally respond to different amounts and kinds of carbohydrate and, if you use insulin, whether your meal doses match. Bring this to your endocrinologist for dose adjustment rather than changing doses on your own.

ADA defines hypoglycemia as blood sugar <70 mg/dL (<3.9 mmol/L); below 54 mg/dL (3.0 mmol/L) is clinically significant, and any low that needs someone else's help to treat is severe. Symptoms include shakiness, sweating, confusion, hunger. Treat with 15 g fast-acting carbs (juice, glucose tabs), recheck in 15 minutes, repeat if still low. Severe hypoglycemia with altered consciousness requires glucagon or emergency care. Log all events — frequent lows indicate need for medication adjustment.

CGMs (Dexcom, Libre, Medtronic) take a reading every few minutes and show trend arrows, and studies show CGM use can lower HbA1c compared with fingersticks alone. But the journal captures context — meal composition, exercise, illness, stress — that CGMs miss. Use both: CGM for granular data, journal for the explanatory narrative. ADA increasingly recommends CGM for type 1 and intensively-managed type 2.

ADA categorizes: rapid-acting (lispro, aspart, glulisine) given before meals; long-acting (glargine, detemir, degludec) once or twice daily for basal coverage; premixed combinations. Write the insulin name in the medication column and the units in the insulin column; the time column records when you took it. Bring 2+ weeks of journal pages to your endocrinologist — basal/bolus adjustments depend on patterns invisible to single-point HbA1c.

Per ADA: aerobic exercise typically lowers glucose during and 24+ hours post-exercise; resistance training may raise it acutely. Illness, infection, and steroid use raise glucose substantially. Note these in the notes column — they explain readings that would otherwise look erratic. Sick-day protocols (test every 2–4 hours, maintain hydration, check ketones if type 1) should be reviewed with your diabetes team.

Very high readings with symptoms such as vomiting, abdominal pain, fruity breath, or rapid breathing can signal DKA — an emergency. If readings stay high, check ketones as your care team has advised (often from about 240 mg/dL, 13.3 mmol/L); moderate or high ketones need urgent medical advice. Severe hypoglycemia with confusion needs glucagon and emergency care. Document all events — frequent extremes signal the need for treatment intensification.