Fasting with a chronic condition

What is it?

Fasting in Ramadan is from dawn to sunset, and the British Heart Foundation (BHF) states that many people with heart and circulatory disease can fast safely during the month.

The IDF-DAR guide states that changes in eating habits in Ramadan may affect blood sugar level, so it is important to measure it often.

Kidney Care UK states that fasting may require adjusting medicines even for kidney patients in the low or moderate risk category.

Why it matters

The World Health Organization (Regional Office for the Eastern Mediterranean) warns that misinformation about fasting and diabetes spreads as Ramadan approaches and may put lives at risk, and calls for correcting it to help people with diabetes make healthy and safe decisions.

The IDF-DAR guide states that the risks of fasting for a person with diabetes include hypoglycaemia, high blood sugar, dehydration and diabetic ketoacidosis.

The NHS Scotland page mentions the risk of dehydration, especially with long fasting hours and hot climates, and the risk of sudden kidney failure in those prone to dehydration such as older people and those with impaired kidney function.

The BHF states that someone who has recently had a heart attack, stroke, stent or bypass surgery is more prone to additional heart problems if they do not eat and drink as usual.

Key points

Risk categories for people with diabetes according to the IDF-DAR guide: Category 1 "very high risk", whose members must not fast, and includes for example severe and repeated hypoglycaemia in the three months before Ramadan, diabetic ketoacidosis, uncontrolled type 1 diabetes, acute illness, kidney problems, pregnancy, heart problems, and advanced age with ill health.

Category 2 "high risk", whose members are advised not to fast, and includes according to the guide: uncontrolled type 2 diabetes, type 1 or type 2 diabetes treated with insulin injections, pregnancy, kidney problems or other diabetes complications, strenuous physical work, and treatment with medicines that may affect mental function. Pregnancy and kidney problems appear in both categories, and the doctor is the one who determines the category.

Category 3 "moderate/low risk": well-controlled type 2 diabetes treated with lifestyle change or tablets or injectable medicines, and the decision to fast in it is according to the doctor's opinion and the person's ability to tolerate fasting. The guide stresses: consult your doctor before deciding to fast whichever your category.

When is the fast broken? According to the IDF-DAR guide: if blood sugar is below 70 mg/dL (3.9 mmol/L) or above 300 mg/dL (16.6 mmol/L), with re-measuring it after one to two hours.

The NHS Scotland page mentions breaking the fast immediately if blood sugar is below 4 mmol/L with treating the low, or above 16 mmol/L. Diabetes UK states to break the fast if sugar falls below 4 mmol/L, and as for the upper limit it asks you to ask the health team what number suits you.

Diabetes UK says that if diabetes is not controlled before Ramadan, fasting will not be a safe option that year.

Kidney patients according to Kidney Care UK: those with stable kidney disease and stable kidney function are in the low or moderate risk category; those with unstable kidney function or stage 4 and 5 chronic kidney disease are in the high risk category (advised not to fast) or very high risk (must not fast), and dialysis patients of all types are in the very high risk category.

How to put it into practice

Before Ramadan: the World Health Organization recommends that people with diabetes consult their doctor to make a safe fasting plan or suitable alternatives. Kidney Care UK advises kidney patients to meet the primary care doctor or kidney team four to six weeks before Ramadan.

What to discuss with the doctor according to Diabetes UK: blood test results, the diabetes medicines you take, and the complications you have or your risk of developing them.

Medicines: a regional NHS page advises continuing prescribed medicines in Ramadan, while asking the doctor or pharmacist whether doses or timing need adjusting. The IDF-DAR guide states that the treatment plan may require adjusting the timing, dose or type of medicine. Do not change or stop your medicine on your own; the adjustment is decided by the doctor.

Measuring sugar: the World Health Organization recommends that people with diabetes measure sugar regularly even while fasting and act immediately on any low or high. The IDF-DAR guide suggests times for measuring: at suhoor, in the morning, at midday, after the afternoon prayer, before iftar, two hours after iftar, and any time symptoms of a low or high appear or you feel unwell.

Meals: the IDF-DAR guide suggests dividing daily calories between suhoor and iftar with one or two light snacks, eating foods rich in fibre and plenty of fruit, vegetables and salads, and not overdoing caffeinated or sweetened drinks and sugary sweets. Diabetes UK advises not skipping the suhoor meal.

At iftar: Diabetes UK suggests that people with diabetes break the fast with a single date or a glass of water. The World Health Organization advises choosing healthy foods at iftar and limiting sugar, fat and salt and avoiding sweetened drinks.

Fluids: the World Health Organization (Regional Office for the Eastern Mediterranean) mentions drinking 8 to 10 glasses of water between iftar and suhoor, and a regional NHS page advises drinking plenty of water before and after fasting and avoiding caffeinated drinks. Anyone who has been told to restrict fluids because of heart or kidney disease should ask their medical team what to do in Ramadan (BHF).

Activity: the World Health Organization recommends that people with diabetes exercise in moderation, such as walking or light exercise after iftar.

Trial run and follow-up: the BHF suggests trying fasting for a few days before Ramadan to see how the body copes, and Kidney Care UK mentions a trial fast before Ramadan among the options discussed with the kidney team. The IDF-DAR guide advises seeing the doctor after Ramadan.

Special groups

Pregnancy and breastfeeding: according to the World Health Organization (Regional Office for the Eastern Mediterranean) the decision for a pregnant woman to fast is made individually in consultation with a healthcare provider, and healthy pregnant and breastfeeding women can usually fast without affecting their health or the child's, with balanced suhoor and iftar meals, delaying suhoor as late as possible, watching for dehydration and drinking enough water after meals, and keeping to regular follow-up.

A pregnant woman with diabetes: the IDF-DAR guide places pregnancy in both the very high risk and high risk categories, so the decision here is for the treating doctor.

Kidney patients: Kidney Care UK suggests spreading fluids over the period between iftar and suhoor rather than drinking a large amount at once, and notes that dates and apricots are rich in potassium so the kidney team or dietitian should be asked about them. It states that blood pressure medicines may need adjusting because going without water may change blood pressure, and the adjustment is decided by the doctor.

Kidney transplant: according to Kidney Care UK it is possible to fast safely one year after a transplant provided there is no kidney rejection and its function is stable, and the decision is for the transplant team.

Heart disease and high blood pressure: the BHF states that some medicines for conditions such as heart failure, diabetes and high blood pressure must be taken regularly, and missing them at their time may make symptoms worse, and advises checking with the pharmacist before changing the routine, and avoiding salt and salty foods because they increase thirst and do not suit blood pressure.

Older people: the IDF-DAR guide places advanced age with ill health in the very high risk category for people with diabetes, and the NHS Scotland page states that older people are prone to dehydration and the resulting risk to the kidneys.

Risks and cautions

Symptoms of low blood sugar that the NHS Scotland page mentions: sweating, trembling, palpitations, double vision, intense hunger, slurred speech, and strange behaviour. It advises that family and friends should also watch for these signs.

Treating a low according to Diabetes UK: break the fast and have a sugary food or drink, followed by something starchy, according to the plan your doctor sets for you.

Signs of dehydration according to the IDF-DAR guide: increased thirst, passing less urine, and a dry mouth, lips and skin. Signs of diabetic ketoacidosis: fruity-smelling breath, dry mouth, and intense thirst.

Diabetes UK states that high blood sugar may cause dehydration so a person feels dizzy and tired, and that untreated high blood sugar may lead to diabetic ketoacidosis, which needs hospital treatment.

Diabetes UK counts as higher-risk groups: people taking medicines that may cause hypoglycaemia, and those with complications such as impaired vision, nerve damage, or heart or kidney disease.

Limits of this information

Some of this page's sources mention that Islam permits the sick to break the fast; the IDF-DAR leaflet cites verse 185 of Surat al-Baqarah, and the NHS Scotland page states that the Quran permits people with an illness or medical condition. This page does not give religious rulings (fatwas), and religious questions (such as alternatives, making up days and matters concerning the validity of the fast) are referred to scholars, as the sources themselves advise asking an imam or scholar.

The numbers for breaking the fast differ slightly between sources (70 mg/dL or 3.9 mmol/L versus 4 mmol/L for a low, and 300 mg/dL or 16.6 mmol/L versus 16 mmol/L for a high), and Diabetes UK asks you to set the upper limit with the health team. The decision to fast, adjusting medicines and sugar targets are individual matters determined by your doctor according to your condition.

We did not find in this page's sources a recommendation for a timing of 6 to 8 weeks before Ramadan; the only timing mentioned is four to six weeks for kidney patients according to Kidney Care UK, and the other sources simply say "before Ramadan". This page relies on the patient-facing leaflet from IDF-DAR, not on the full professional guideline chapters.

Instructions specific to particular medicines or their doses have been deliberately left out; adjusting the type, timing and dose of a medicine is decided by the doctor. The fluid amounts mentioned are general advice that does not apply to someone who has been told to restrict fluids.

Most sources are British or international, and health services differ between countries; so ask your primary care doctor or the health authority in your country.

Common questions