Hypos: tighter control & its impact

David Kinshuck


Fitting tighter control into your lifestyle


Why do hypos happen?


Impact of Hypoglycaemia

Hypoglycaemia (low blood glucose) occurs whenever there is more insulin in the body than is needed. It is usually uncomfortable rather than dangerous, but occasionally blood glucose goes so low that the brain runs out of fuel and ceases to work properly. Confusion, irritability, even unconsciousness, can result.

A severe hypo leaves the person with diabetes unable to help themselves and needing help from someone else. This unpleasant, embarrassing and potentially dangerous complication of insulin treatment is not very common. However, those people on intensive insulin treatment are at greater risk. Why?


Hypo warning symptoms

Hypo warning symptoms
  • shaky, tremors
  • sweaty
  • hot
  • cold
  • very hungry
  • drowsy
  • convulsions
  • confusion
  • anger, irritation
  • running away
  • laughing, silliness
  • palpitations
  • high stress/emotions
  • an early morning headache like a hangover


Usually, your body recognises a small fall in blood glucose and tells you about it long before you have any confusion or inability to cope. Early warning symptoms of hypos include feeling sweaty, shaky, hot, cold, anxious, very hungry or drowsy. You may also lose your concentration, have difficulty speaking and become irritable.

When you feel these symptoms, you should (ideally!) check your blood glucose and if it is low, correct it by eating something rich in carbohydrate immediately. You are only at risk of greater confusion and perhaps loss of consciousness if your blood glucose continues to fall.


Losing your hypo warning signs... 'hypo-unawareness'

Some people lose their early warning symptoms of hypoglycaemia. About a quarter of all people who have had diabetes for a long duration (say more than 15 years), find their hypo symptoms have changed so much that they may miss them altogether. But loss of warning of a hypo does also seem to be more common in people using intensive insulin treatment and may contribute to the increased risk of severe hypos.

This is partly because there is less leeway with tight diabetes control; if your background blood glucose is nearly normal, a small drop in blood glucose, perhaps from unexpected exertion or a late snack, may take you really low. As a result, you may be too confused by the time the symptoms arrive to recognise them for what they are. See case

A common reason for having too many hypos that you are not aware of is that you are simply having too many, and your body cannot cope, wearing out (temporarily) the body's warning system. The repeated undetected periods of hypos (<3.5 mmol/l) often for extended periods, commonly at night.


Hypo-unawareness..possible causes

When hypos are serious are frequent, review possible contributory causes (NICE 2004):

Anyone with hypos needs the help of their diabetes nurse /doctor. If the cause is unclear, a glucose monitor may help. These can monitor glucose levels overnight, and l can tell your nurses when your hypos are coming.


Who is at risk?

Hypos are slightly more common at night. About half of the daytime episodes apparently occurred without proper warning symptoms. Severe hypos are more common with intensive insulin treatment....for every 1% lowering of glycated haemoglobin (HbA1c), there is a 36% increase in risk DCCT).

A hypo can occur at high glucose levels. If a person normally has a glucose level of 15mmol/l, then even a drop to 10 can cause a hypo. Commonly, if the glucose is normally 9, then a level of 5 may cause a hypo. However, the most serious hypos occur at much lower glucose levels. So if a person is very well controlled, with normal glucose levels of 5-6mmol/l, the such a patients will occur is levels drop to 2 or less (and at this level the hypos may be severe with unconsciousness) .


So should I improve my diabetes control?

Generally the risk of hypos should not stop you trying to improve your control. We have learnt a lot about hypos and what contributes to the risk of having severe ones. In the DCCT itself, the frequency of severe hypos declined as time went on and people started to understand the causes of severe hypos.


When is tight control not advisable?

People on tight control in the DCCT who experienced more hypos said that hypos did not affect their quality of life. But there are some groups of people who should be wary of keeping their blood glucose levels too tightly controlled because of potential hazards should severe hypos occur. They include:

There is no proven advantage either for people who already have advanced complications such as severe visual loss or kidney failure (though there were no such people in the DCCT).


Defining your 'lower limit'

Including a lower limit in definitions of 'good' diabetes control is very important. The DCCT researchers decided that very low blood glucose levels (around 3-4 mmol/l) were something to be avoided and that blood glucose should be kept above 3.6 mmol/l in the middle of the night. Research studies have shown that eliminating hypoglycaemia from daily life may even restore warning symptoms of the occasional hypo that may creep in!


How do I avoid too many hypos?

Think about (and check) your blood glucose readings when you think you might be most at risk.



Alcohol increases susceptibility to hypos as it affects glucose metabolism and reduces the warning signs. Binge drinking is dangerous in diabetes, but if you 'have to' binge drink, maintain higher than usual glucose levels, and test your glucose levels more often, especially in the night after the binge.



Discussed in more detail here. If you play a round of golf for instance, to prevent a hypo you should reduce the dose of the previous insulin injection, both short and long acting types. If you forgot to do this, or did not have chance to plan ahead, expect a hypo: test your glucose before and half way round if you get the chance, but if not have something extra to eat before you start, and half way round. Test when you finish, as you may need something to eat then as well.

If you have a lot of vigorous exercise during the day, you need a lot less insulin (a 30-50% reduction may be needed). If you do not have chance to reduce your insulin both in advance and after the exercise, you may get a hypo in the evening or even in the night. So reduce your insulin, and eat more, and test often. (Even in the evening after the vigorous exercise.)

Eventually you will learn how to make the adjustments and have very few hypos, but it takes a lot of practice and testing, and advice from you diabetic nurse. Try and increase your exercise gradually to avoid this. If you exercise at weekends only, and have a desk job during the week,remember you will need vastly different insulin doses at the weekends. With planning, testing, and adjusting doses, good control is still achievable.



When you have an infection your glucose goes up and you need more insulin. When the infection goes you will have to reduce your insulin, so be prepared, test, adjust, and look out for a hypo.


Prepare for hypos

If you are driving, always have a few cartons of orange juice with you. A salad sandwich or fruit would be useful as well, reserving sweets as a last resort. If you are changing your insulin regime, have taken more exercise than usual, or feel sick, a hypos may be more likely. Generally insulin users should test their glucose level before starting to drive and every 90 minutes.


What to do if you get a hypo

Hypo treatment.... lucozade, carton orange juice, dextrose tablet, followed by complex carbohydrate such a a bandana or sandwich. Naturally this depends on the hypo, and it is better to try and predict one and take preventative action. In practice many people with diabetes do notice occasional hypos, even if they try really hard to avoid them.

If you think you are getting hypos regularly YOU MUST TEST YOUR GLUCOSE/SUGAR to confirm they are hypos if you are to have any chance of controlling your diabetes properly.



A glucagon injection can be injected by someone else if you have a severe hypo, although you need a glucosey drink afterwards. Intramuscular glucagon (0.5-1mg...the higher dose may produce vomiting particularly in children).

It is not effective in alcoholics. After recovery, have some oral carbohydrate, such as a glucosey drink or orange juice, followed by a sandwich or some other carbohydrate. There should be a response in 10 minutes (otherwise intravenous glucose is needed.) This website cannot advise relatives when to call a paramedic, but if you are not sure what is going on, it is best to call for urgent paramedic help.

After recovery from the glucagon you need to contact your nurse/doctor for advice.


Treatment of hypo-unawareness/frequent hypos

Treatment of hypos at night

Hypos at night may be noticed by patients or detected by implantable monitors (available for a few days from hospital diabetic clinics) should be managed by:

Achieving success

What if you have had bad hypos recently and are afraid of trying to lower your average blood glucose level? Suppose you've dealt with the problem by relaxing your diabetes control until your blood glucose are always high (say over 9 mmol/l) and you've stopped the hypos but now have a high HbA1c with its increased risk of long term diabetes complications.

Remember that the risk of diabetes complications is almost directly related to the value of the glycated haemoglobin (HbA1c) and almost any reduction In average blood glucose and HbA1c will now be useful.

Don't give up just because you despair of perfection - it is worth lowering your HbA1c as much as you can without starting to hypo again. And look very carefully at the spread of your home blood glucose readings -getting rid of those under 4 mmol/l readings may be all you have to do!

We now know that the better your blood glucose control over the years, the better your chances of avoiding diabetic complications. And we also know that really good control means avoiding hypos too --both the severe and mild ones. Visit the AIDA computer model of insulin/glucose levels.