Alcohol and blood glucose levels
Alcohol can increase the blood glucose level in the short term if the drink contains carbohydrate, but increase the risk of hypoglycaemia (low glucose) in the medium to long term.
Frequently asked questions
Q. Why am I at risk of having a hypo if I drink alcohol?
A. You are at risk because the liver is processing the alcohol you have drunk and cannot release any supplies of stored glucose at the same time. The more alcohol you drink, the bigger the risk. This means you might need to reduce your insulin dose in the evening and again at breakfast time, or eat more carbs before bed and the next day at breakfast.
Q. Should I test my blood glucose when I’m out, especially if I start to feel drunk?
A. This is very important, even if it is a bit inconvenient to carry your blood glucose meter with you every time you go out. The trouble is that if you don’t test when you are out drinking, the alcohol might be having a huge effect on your blood glucose without you being aware of it, as the symptoms of high and low blood glucose can easily be mistaken for just being drunk.
“I wouldn’t dare go out without a meter. I’ve sometimes not realised that I’m going hypo and just thought I was really drunk. Once I ended up in A&E and was so embarrassed the next day when I woke and sobered up“
Q. Should I carry some glucose with me?
A. This is very important. It’s not really a major issue if your blood glucose levels drop when you’re in a bar and can buy a normal coke, which contains glucose. But if you’re on your way home and there aren’t any shops open, or if you stay overnight with a friend, it might be dangerous to be without any glucose tablets.
Q. Could I have a hypo the following morning after going out drinking?
A. This is common and usually depends on the amount of alcohol that has been drunk the night before. The liver can take a while to process alcohol and so the risk of having a hypo can last for a good while after your last drink. It’s important to set your alarm clock just to make sure you don’t sleep through a hypo which can be serious and might mean you need medical help. At breakfast, you may need to either eat extra carbs or reduce your dose of fast-acting insulin. Test your blood glucose regularly.
Q. Is it a good idea to carry ID?
A. You should definitely do this in case you have a hypo, or need medical help for a different reason and especially if you are with people who don’t know you have diabetes. In addition, many clubs and bars might not let you in if they see you are carrying insulin pens/syringes or blood glucose testing equipment.
Q. Should I tell my friends about hypos?
A. You may not realise you are experiencing a hypo, so it’s very important that at least one or two of your friends can recognise the symptoms and make sure you’re aware you’re having one. They should also be able to spot the symptoms of a more severe hypo and be able to help you by giving you the appropriate treatment.
You should warn your friends that if you start acting strangely or shaking/sweating, then they should insist that you check your blood glucose. This is especially important if you are staying with them overnight or going on holiday together. Make sure they know that you can have a hypo in your sleep.
“My best pal always knows if I’m going low when I’m drinking even before I realise. We’ve had a few arguments, mind, when she tells me to check my blood and I say I’m fine. I now know, though, to do as she says as she’s always been right! Sometimes it’s hard to pick up that you’re going low and you think you’re just drunk, and it’s nice having someone to go to the toilet with you to check”.
Q. Could my blood glucose rise if I drink alcohol?
A. It will if you’ve had any drinks containing sugar. Have a look at this Carb & Cals pdf that explains more about the carbohydrate content in alcohol. You should avoid high carb drinks where possible. However, if you are going out, being active and drinking over an extended period of time then alternating between low and higher carb drinks can be a safer way to keep blood glucose levels stable.
If you are starting out, do not count carbs in alcohol. Over time and with regular blood glucose monitoring, you will learn whether you need to take a small amount of insulin to cover high carbohydrate drinks (e.g. cider, lager) to correct high blood glucose levels, or whether you can manage them through alternating between higher and lower carb drinks.
To reduce the risk of blood glucose dropping overnight, have a carbohydrate supper uncovered by insulin before bed and/or reduce your evening basal insulin dose. Make sure you have your glucose monitor and hypo treatment at the side of your bed just in case you need it.
Q. Is there anything else I need to bear in mind about going out drinking?
A. There are other aspects to going on a night out that might affect your blood glucose levels:
- Playing sport before you go to the pub, dancing, walking home, sex: these are all forms of exercise and can put you at risk of a hypo.
- A takeaway on the way home, or eating something carb-laden before you go to bed could send your blood glucose much higher than it should be.
- If you are having a long lie-in the next day, your blood glucose could go either way: miss your breakfast insulin dose and lie around in bed and your level could be too high, but you may also be at risk of a delayed hypo after drinking alcohol and even more so if you skip breakfast too.