It is 4 a.m. and your father, who has had diabetes for fifteen years, is sweating through his kurta, talking in confused half-sentences and refusing to wake up properly. The night before, he skipped dinner after a heavy evening snack at a wedding but still took his usual glimepiride tablet. What looks like a "weakness" episode is actually hypoglycaemia, or low blood sugar, and it is one of the most common and most preventable emergencies in Indian homes.
With an estimated 10.1 crore Indians living with diabetes (ICMR-INDIAB study, 2023) and many of them on sulfonylureas or insulin, low blood sugar is something every diabetic family should know how to spot and treat. Indian studies suggest it is far more frequent than most people think: a survey from Madurai found that around 40% of patients on sulphonylureas reported mild symptomatic hypoglycaemia, and many episodes go unrecognised, especially at night and in the elderly. This guide explains what counts as low blood sugar, the warning signs, how to treat it with foods already in your kitchen, who is most at risk, and how to stop it from happening again.
What Is Hypoglycaemia (Low Blood Sugar)?
Your brain runs almost entirely on glucose. When blood glucose falls too low, the body first raises an alarm through adrenaline (shaking, sweating, racing heart), and if the level keeps falling, the brain itself starts to malfunction (confusion, odd behaviour, seizures, unconsciousness).
Hypoglycaemia is defined as a blood glucose level below 70 mg/dL. International diabetes organisations, including the American Diabetes Association (ADA), classify it into three levels:
| Level | Blood glucose | What it means | What to do |
|---|---|---|---|
| Level 1 (alert) | 54-69 mg/dL | Low; may or may not have symptoms | Treat with 15 g fast sugar, recheck |
| Level 2 (clinically significant) | Below 54 mg/dL | Seriously low; brain starts to be affected | Treat immediately; inform your doctor |
| Level 3 (severe) | Any value, with confusion or unconsciousness | Needs another person's help to recover | Emergency: glucagon or hospital |
For comparison, a normal fasting blood sugar is 70-99 mg/dL, as explained in our fasting, PP and random blood sugar guide.
Can people without diabetes get low sugar?
True hypoglycaemia in people without diabetes is uncommon. Many people describe feeling "low" when they are hungry, but their actual sugar is normal. Genuine causes in non-diabetics include:
- Heavy alcohol intake on an empty stomach (alcohol blocks the liver from releasing glucose)
- Reactive hypoglycaemia, a drop 2-4 hours after a high-carbohydrate meal, sometimes seen after bariatric or stomach surgery
- Severe illness: liver failure, kidney failure, sepsis, severe malaria (and quinine treatment)
- Hormone problems: low cortisol (adrenal insufficiency), as covered in our cortisol test guide
- Rare tumours such as insulinoma, which make too much insulin
- Prolonged fasting or severe malnutrition
If someone without diabetes has a documented sugar below 55 mg/dL with symptoms that improve after eating, they need medical evaluation.
Symptoms of Low Blood Sugar: Know the Warning Signs
Symptoms come in two waves. Recognising the first wave early gives you time to act before the second wave arrives.
Early warning signs (adrenaline response)
- Shaking or trembling hands
- Sudden sweating, often cold and clammy
- Pounding or racing heartbeat
- Intense hunger
- Anxiety, irritability or a sense of panic
- Tingling around the lips or fingers
- Pale skin
Later signs (brain running short of glucose)
- Confusion, difficulty concentrating or answering simple questions
- Slurred speech, behaving as if drunk
- Blurred or double vision
- Weakness, unsteady walking, falls
- Unusual stubbornness or aggression (common in elderly parents)
- Seizures or fits
- Loss of consciousness
Night-time hypoglycaemia
Low sugar during sleep is easily missed. Clues include nightmares, night sweats that soak the bedsheet, waking with a headache, or feeling unusually tired and "hungover" in the morning. A morning fasting sugar that is unexpectedly high can sometimes follow a night-time low as the body overcorrects.
Hypoglycaemia unawareness
People who have had diabetes for many years, who have frequent lows, or who take beta blockers (such as metoprolol or atenolol for blood pressure) may lose the early warning signs. They go straight from feeling fine to confusion. This is called hypoglycaemia unawareness and it is dangerous, particularly for those who drive, live alone or are elderly. Discuss it with your doctor; relaxing sugar targets for a few weeks can often restore the warning signs.
A useful rule for families: if a person with diabetes is behaving strangely, check the sugar first. Low sugar is frequently mistaken for a stroke, a "BP problem", drunkenness or simple tiredness.
How to Treat Low Blood Sugar: The 15-15 Rule, Indian Style
If someone is conscious and able to swallow, follow the 15-15 rule:
- Check blood sugar with a glucometer if one is available. If not, and symptoms are present, treat anyway.
- Take 15 grams of fast-acting sugar (see the table below).
- Wait 15 minutes, then recheck.
- If still below 70 mg/dL, take another 15 g and recheck again after 15 minutes.
- Once above 70 mg/dL, eat a small snack with starch and protein if the next meal is more than an hour away, such as two biscuits with milk, a roti with dal, or a slice of bread with peanut butter.
What counts as 15 grams of fast sugar?
| Option | Approximate amount for 15 g |
|---|---|
| Glucose powder (Glucon-D, Glucose-D) | 3-4 teaspoons dissolved in water |
| Table sugar | 3 teaspoons in half a glass of water |
| Honey | 1 tablespoon |
| Regular soft drink (not diet or zero) | Half a glass (about 150 ml) |
| Fruit juice (packaged or fresh) | Half a glass (about 120-150 ml) |
| Glucose tablets | 3-4 tablets (check the label) |
| Hard toffees | 3-4 pieces, chewed |
Common mistakes Indian families make
- Using chocolate, mithai or biscuits as the first treatment. The fat in chocolate, ladoo, barfi and cream biscuits slows sugar absorption. Use pure glucose or sugar water first; the snack comes later.
- Overtreating. Eating half a box of sweets out of panic leads to a sugar of 300+ mg/dL a few hours later. Stick to 15 g and recheck.
- Using "sugar-free" products. Diet colas and sweeteners like sucralose or stevia do nothing for hypoglycaemia.
- Patients on acarbose (Glucobay) or voglibose (Volix, Voglibite): these medicines block table sugar from being broken down. If you take them, use glucose powder or tablets, not sugar or juice.
When the person cannot swallow or is unconscious
Never put food, water or sugar in the mouth of an unconscious person; they can choke. Instead:
- Turn them on their side (recovery position).
- If a glucagon injection (such as GlucaGen HypoKit) is available at home and a family member has been trained, inject it into the thigh or arm as instructed. Glucagon makes the liver release stored glucose and usually works within 10-15 minutes.
- Call 108 or 102 and take them to the nearest hospital. Doctors will give intravenous dextrose.
- Once awake and able to swallow, give fast sugar followed by a proper meal.
Glucagon is less useful in people who have been drinking heavily or are severely malnourished, because their liver glucose stores are low. Ask your diabetologist whether a glucagon kit is worth keeping at home, particularly for children with type 1 diabetes, as discussed in our type 1 diabetes in children guide.
After a sulfonylurea-related low
Lows caused by sulfonylureas can recur for 24-72 hours because the tablet keeps working long after the first episode is treated. An elderly patient who had a severe low on glibenclamide should be observed in hospital, not just given sugar and sent to sleep.
Who Is at Risk? Medicines and Situations That Cause Low Sugar
Diabetes medicines and their hypoglycaemia risk
Not all diabetes medicines cause low sugar. Knowing which ones do helps you understand your own risk.
| Medicine group | Common Indian brands | Risk of low sugar |
|---|---|---|
| Insulin (all types) | Actrapid, Insugen, Mixtard, Huminsulin, Lantus, Basalog, Tresiba, NovoRapid | High, especially with dose errors or skipped meals |
| Sulfonylureas | Glibenclamide (Daonil, Euglucon), glimepiride (Amaryl, Glimy), gliclazide (Diamicron, Reclide), glipizide (Glynase) | Moderate to high; glibenclamide highest |
| Meglitinides | Repaglinide (Eurepa), nateglinide | Moderate |
| Metformin | Glycomet, Glyciphage, Obimet | Low when used alone |
| DPP-4 inhibitors | Sitagliptin (Januvia, Istavel), vildagliptin (Galvus), teneligliptin (Ziten) | Low alone |
| SGLT2 inhibitors | Dapagliflozin (Forxiga), empagliflozin (Jardiance) | Low alone |
| GLP-1 agonists | Semaglutide (Rybelsus, Ozempic), tirzepatide (Mounjaro) | Low alone, but higher when combined with insulin or sulfonylureas |
Fixed-dose combinations such as glimepiride + metformin (very widely prescribed in India) carry the sulfonylurea's risk. Newer sulfonylureas like gliclazide MR and glimepiride have a lower risk than glibenclamide, which many doctors now avoid in elderly patients. If you are on an older medicine and having frequent lows, ask your doctor whether a switch makes sense. Our diabetes management guide and Mounjaro guide cover these medicines in more detail.
Situations that trigger lows in Indian households
- Skipped or delayed meals: late lunch at the office, travel, attending a long puja or function
- Religious fasting: Navratri, Karva Chauth, Ekadashi, Ramzan, Shravan Mondays. A multi-country study of sulfonylurea users during Ramzan found symptomatic hypos in about 1 in 5 participants (13% in the Indian group). See our Navratri fasting and diabetes guide for safe fasting.
- Unplanned exercise: an unusually long morning walk, gardening, playing with grandchildren
- Alcohol, especially without food; lows can appear many hours later, even the next morning
- Kidney disease: reduced kidney function keeps insulin and sulfonylureas in the body longer. If creatinine is rising (see our CKD guide), medicine doses often need lowering.
- Weight loss or improved diet: after losing weight, the old doses may become too strong
- Vomiting, diarrhoea or poor appetite during illness (fever, dengue, gastroenteritis) while continuing usual doses
- Insulin errors: injecting before a meal that is then delayed, mixing up pens, injecting into a muscle by mistake
- Old age: elderly people often eat less, have kidney decline and may forget whether they took their tablet
Preventing Low Blood Sugar: A Practical Plan
Everyday habits
- Never skip a meal after taking a sulfonylurea or mealtime insulin. If you know a meal will be delayed, ask your doctor in advance how to adjust.
- Carry a "hypo kit": glucose powder sachets or toffees in your bag, car and office drawer.
- Check sugar before driving, and do not drive if it is below 90 mg/dL.
- Eat before exercise if you are on insulin or sulfonylureas, and carry sugar on walks.
- Limit alcohol, never drink on an empty stomach, and have a carbohydrate snack before bed if you drank.
- Use a pill organiser for elderly parents so tablets are neither missed nor doubled.
Monitoring
- Glucometer checks: if you are on insulin or sulfonylureas, check at different times of the day, including occasionally at 2-3 a.m. if you suspect night-time lows.
- Continuous glucose monitors (CGM), now widely available in India, record readings every few minutes and are excellent at uncovering hidden lows. Read our CGM guide.
- HbA1c is not enough: a "good" HbA1c of 6.2% in an elderly person on sulfonylureas can hide frequent lows. Many doctors aim for a relaxed target of 7.5-8% in older adults to keep them safe. See our HbA1c guide.
Keep a hypo diary
Every time a low happens, note the date, time, reading, symptoms, what you ate, activity, medicines taken and how you treated it. Patterns become obvious within a few weeks: lows every Sunday after a long walk, or every night after a light dinner. Take this diary to every appointment.
This is where organised records make a real difference. Upload your glucometer logs, CGM reports, HbA1c and kidney function results to MedicalVault, and use trend analysis to see whether your HbA1c is dropping too fast or your creatinine is rising, both of which can signal a need to reduce medicine doses. With family sharing, adult children living in another city can see their parents' reports and spot warning patterns early.
Educate the whole family
Everyone in the house, including domestic helpers, should know:
- What low sugar looks like in your family member
- Where the glucose powder and glucometer are kept
- The 15-15 rule
- Never to give anything by mouth if the person is unconscious
- When to call 108
When to See a Doctor
Contact your doctor promptly if:
- You have more than one or two lows a week
- You have had any level 2 or level 3 episode
- Lows happen at night or without warning symptoms
- You have recently lost weight, changed diet, or been diagnosed with kidney problems
- You are planning to fast for a festival or religious reason
- An elderly family member has had an unexplained fall, confusion or a "fit"
Never stop or change your diabetes medicines on your own. Your doctor may reduce doses, switch from glibenclamide to a safer agent, or change your insulin regimen.
Key Takeaways
- Hypoglycaemia means blood sugar below 70 mg/dL; below 54 mg/dL is serious, and any episode needing someone else's help is severe.
- Insulin and sulfonylureas (glibenclamide, glimepiride, gliclazide) cause most lows; metformin, DPP-4 and SGLT2 medicines rarely do on their own.
- Treat with the 15-15 rule: 15 g of glucose powder, sugar water, honey or juice, recheck after 15 minutes, then eat a snack. Avoid chocolate or mithai as first treatment.
- Never feed an unconscious person; use glucagon if available and call 108.
- Skipped meals, festival fasting, alcohol, kidney disease and old age are the biggest triggers in Indian homes.
- A very low HbA1c in an elderly person can be a warning sign, not an achievement. Discuss safer targets with your doctor.
- Keep a hypo diary and organise your sugar records in MedicalVault so you and your doctor can see patterns over time. Explore our features page to learn how family sharing helps you look after parents from anywhere.