Low Blood Sugar in Older Adults: Recognising and Treating It

What counts as low

Doctors commonly define hypoglycaemia as a blood glucose below 70 mg/dL (about 3.9 mmol/L). Below about 54 mg/dL it is considered serious. Some older adults feel symptoms at higher numbers, particularly if their sugar usually runs high and falls quickly, and others feel nothing even at low numbers. Always treat symptoms and low readings, and check with a meter whenever possible. See fasting and post-meal sugar readings for context on ranges.

Who is at risk

Low sugar mostly happens in people taking insulin or certain diabetes tablets such as sulfonylureas. It can also happen in people who:

• Skip or delay meals, or eat less than usual because of illness, poor appetite or dental problems.
• Are more active than usual, for example a long walk or a day of cleaning before a festival.
• Drink alcohol, especially on an empty stomach.
• Have kidney disease, which slows clearance of some medicines and insulin.
• Have liver disease, heart failure or frailty.
• Are underweight or have lost weight.
• Have had recent changes in medicines, as advised by a doctor.
• Live alone and have memory problems, and may take a dose twice by mistake.

If your parent has had even one episode, tell the doctor. Asking the doctor to review the medicines is appropriate; changing them yourself is not.

Why it is easy to miss in older adults

• Different symptoms. Confusion, behaviour change, slurred speech, dizziness, falls, weakness and sleepiness may appear without sweating or shaking.
• Reduced warning signs. Some people develop "hypoglycaemia unawareness" and do not feel the early warnings.
• Medicines that mask signs. Beta-blockers, used for blood pressure and heart conditions, can hide a racing heartbeat and tremor, though sweating may remain.
• Dementia and stroke. A person may not be able to say what they feel.
• Night-time lows. They may cause restless sleep, nightmares, night sweats or morning headache. See diabetes and low-sugar emergencies for a family plan.

Because confusion can be mistaken for a dementia flare, stroke or ordinary tiredness, check blood sugar whenever your parent with diabetes is suddenly odd. See also delirium in older adults.

Signs to look for

Early or mild:

• Hunger, sweating, shakiness, pale skin.
• Fast heartbeat, anxiety, tingling around the mouth.
• Headache, blurred vision, dizziness.
• Weakness, irritability, unusual mood.

Moderate:

• Confusion, difficulty concentrating, slurred speech.
• Clumsiness, unsteady walking, falls.
• Drowsiness, strange behaviour.

Severe:

• Unable to swallow safely, not responding properly.
• Seizure, fainting, unconsciousness.

What to do for a mild or moderate episode

If your parent is awake and able to swallow safely:

1. Test blood sugar with a meter if one is at hand, but do not delay treatment if testing will take long or your parent is very unwell. 2. Give about 15 grams of fast-acting sugar. Options include three or four glucose tablets, half a glass (about 120 ml) of fruit juice or a sugary soft drink, or three teaspoons of sugar dissolved in water, or honey. Avoid chocolate, biscuits or fatty foods as the first treatment, because they raise sugar slowly. 3. Wait 15 minutes and recheck. If still below 70 mg/dL or symptoms continue, repeat the 15 grams. 4. Once sugar is back up, give a small snack or meal, such as a slice of bread, a banana or the next planned meal, to prevent sugar dropping again, especially if the next meal is more than an hour away. 5. Rest for a while and do not leave your parent alone for the next hour or so. Avoid walking, bathing or stairs until fully recovered. 6. Tell the doctor about every episode, even if mild, the same day if possible. Write down the time, reading, what was eaten and medicines taken.

This "rule of 15" is widely taught, but your doctor may recommend variations, particularly for those on certain tablets or with kidney disease. Follow the plan your doctor has written.

What not to do

• Do not put food or drink into the mouth of someone who is unconscious, convulsing or cannot swallow. It can cause choking. Place them on their side and call 112.
• Do not give insulin or extra tablets "to balance things out".
• Do not wait and see if symptoms worsen.
• Do not drive or let your parent drive after a low until the doctor says it is safe.
• Do not use sugary food as a routine fix to run sugar high on purpose; that can cause other problems. Ask the doctor about the right balance.

Severe episodes

For a person who is unresponsive, having a seizure or unable to swallow:

• Call 112 at once.
• Place the person on their side in the recovery position, loosen tight clothing, protect from injury and do not put anything in their mouth.
• If the doctor has prescribed glucagon and you have been trained to use it, give it as instructed. Many families in India do not have it, so ask your doctor whether it is suitable and how to obtain and store it.
• Stay with the person until help arrives and tell the paramedics what medicines were taken and when.

After any severe low, your parent needs a medical review.

Preventing lows

• Regular meals and snacks. Do not skip meals after taking diabetes medicine. Ask the doctor what to do when appetite is poor or when fasting for religious reasons or tests. Do not self-adjust.
• Careful medicine routine. Use a pill organiser and a written chart so doses are not doubled. See dementia and medicines: managing safely.
• Know the risky times. Check sugar before driving, exercise, bedtime and when unwell.
• Carry fast sugar. Keep glucose tablets or sugar sachets in a pocket, handbag, bedside table and near the meter.
• Limit alcohol.
• Plan exercise with the doctor.
• Regular review of medicines by the doctor, especially if weight, kidney function or appetite has changed. See polypharmacy and deprescribing.
• Wear identification that states diabetes and medicines.
• Teach family and neighbours the signs and the 15 gram rule, and where the sugar is kept.

Using the meter

A working meter and in-date strips are important so that you can confirm a low and track recovery. Keep the kit in an easy-to-reach box. See how to test blood sugar at home step by step and glucose strips and lancets guide. For some people, continuous sensors with alarms can warn of falling sugar; see continuous glucose monitors for older adults.

Indian household tips

• Keep a sealed packet of glucose powder or tablets in several rooms, and check expiry, since sugar can get damp in the monsoon.
• Remember that tea with milk and a little sugar works slowly. A plain sweet drink or glucose water works faster.
• During fasts and festivals, talk to the doctor in advance about a plan.
• If your parent lives alone, ask a neighbour or relative to phone daily, especially in the morning.
• Keep the doctor's number and 112 on the fridge door.

After an episode

Write down what happened. Look for a trigger, such as a missed meal, extra walk, new medicine, illness or alcohol. Share it with the doctor, who may adjust treatment or targets, which may be relaxed for older adults to reduce the risk of lows. Never make those changes yourself.

When to ask a professional

Call the doctor the same day after any low reading or episode, and ask for a review of medicines, targets and meal plans. Ask a dietician about meal timing. Seek urgent help if lows are frequent, happen at night, or if your parent does not feel them coming. Call 112 for unconsciousness, seizure, inability to swallow, or no improvement after two treatments.