If you live with diabetes, you will almost certainly have been told to look after your feet. But the advice often stops there — without a real explanation of why blood sugar control is so directly connected to what happens below your ankles.
Having spent over a decade working with diabetic patients in the NHS, I want to give you a clearer picture of what is actually going on, so that the foot checks and blood sugar monitoring you are doing feel less like box-ticking and more like something that genuinely matters.
What high blood sugar does to the nerves in your feet
Over time, persistently raised blood glucose damages the small nerve fibres that carry sensation to your feet and lower legs. This is called peripheral neuropathy, and it affects roughly half of all people with diabetes at some point.
The practical effect is that your feet become less able to detect pain, heat, and pressure. That might not sound serious, but consider what pain actually does for you — it tells you when something is wrong. A blister from a new shoe. A small cut on the sole. A piece of grit inside a sock. Without that warning system, injuries can go unnoticed and untreated for days or even weeks.
By the time the problem becomes visible, it may already be infected or difficult to heal. In the most severe cases, untreated wounds can lead to ulceration and, in a small proportion of patients, amputation. The vast majority of diabetes-related amputations are preceded by a wound that could have been caught and treated early.
Worth knowing: Peripheral neuropathy is not inevitable. Good glycaemic control — keeping your HbA1c within the range your GP or diabetes team has set — is the single most effective thing you can do to slow or prevent nerve damage from progressing.
What high blood sugar does to circulation
Alongside nerve damage, diabetes also affects the blood vessels that supply your feet and legs. This is called peripheral arterial disease (PAD), and it means that blood flow to the extremities is reduced.
Good circulation does a lot of quiet, important work. It delivers oxygen and nutrients to the skin and tissues, fights infection, and — crucially — allows wounds to heal. When circulation is compromised, even a small cut can take far longer to close, and the risk of infection increases significantly.
Reduced circulation can present in a few ways. You might notice that your feet feel cold, look pale or have a bluish tinge, or that hair on your lower legs has thinned. Sometimes there is no obvious sign at all, which is why a proper vascular assessment — not just a visual check — is so important for diabetic patients.
The relationship between HbA1c and foot complications
HbA1c is a blood test that gives a picture of your average blood sugar level over the past two to three months. It is the main measure your diabetes team uses to assess how well your condition is being managed.
The research on this is very clear. For every 1% reduction in HbA1c, the risk of microvascular complications — including nerve damage and the small blood vessel disease that affects the feet — reduces meaningfully. This is not about achieving perfection. Even modest, sustained improvements in blood sugar control can make a real difference to your risk over time.
This does not mean that foot complications only happen to people with poorly managed diabetes. Some patients develop neuropathy despite good control, and some with higher HbA1c readings have no foot problems for many years. But on a population level, glycaemic control is the most powerful lever we have.
What this means in practice
There are several practical things that follow from understanding this:
Check your feet daily
Because neuropathy may mean you cannot feel a problem developing, a visual check of your feet — including the soles and between the toes, which are hard to see without a mirror — should become part of your daily routine. You are looking for cuts, blisters, redness, swelling, or any change in the skin or nails.
Footwear matters more than most people realise
Poorly fitting footwear is responsible for a very large proportion of the foot injuries that lead to serious complications in diabetic patients. Shoes that are too tight, too loose, or have rough internal seams can create pressure points and abrasions that you may not feel. Well-fitting shoes with good depth and a soft interior are an important part of protecting your feet.
Never ignore a wound, however small
Any break in the skin on a diabetic foot should be taken seriously. Clean it gently, cover it with a clean dressing, and if it does not begin to improve within a day or two, see a healthcare professional promptly. Do not be tempted to manage foot wounds at home for extended periods if they are not healing.
Keep your regular diabetes appointments
Your annual diabetic foot check with your GP or practice nurse is an important opportunity to assess your risk level. If you have been missing these, it is worth getting back in the habit.
Seek urgent help if you notice: a wound that is not healing, increasing redness or warmth around a wound, swelling or pus, or any part of the foot that looks dark or feels different. These can be signs of infection and should not be left to resolve on their own.
A note on blood sugar management
Managing blood sugar is genuinely not easy. It involves medication, diet, exercise, stress, sleep, and a host of other factors that interact in complex ways. If you are finding it difficult to keep your levels within range, that is not a failing on your part — it is worth raising with your diabetes team, who may be able to adjust your medication, refer you to a dietitian, or explore other options.
The connection between glycaemic control and foot health is one of the strongest arguments for taking blood sugar management seriously, even when your feet currently feel fine. The damage accumulates quietly, over years, before it becomes visible. Prevention is far easier than treatment.
Summary: High blood sugar damages the nerves and blood vessels in your feet over time. Good glycaemic control is the most effective way to slow this process. Daily foot checks, well-fitting footwear, and prompt attention to any wound are the practical steps that follow from understanding this.
This article is written for general information only and does not replace personalised medical advice. If you have concerns about your feet or your diabetes management, please speak to your GP, diabetes nurse, or podiatrist.