Type 1 Diabetes – Preventing Hypos After Aerobic Exercise

Diabetes & Aerobic Exercise – Paul Coker & Dr Rob Andrews discuss approaches to managing type 1 diabetes  after aerobic exercise.   In this short video Paul asks Dr Andrews what causes blood glucose levels to climb quickly after he crosses the finish line of a long run and asks what the research shows us about managing this.

Introducing Dr Rob Andrews

Dr Rob Andrews, is a consultant at Taunton Hospital where he takes care of people with type 1 diabetes. As part of that he runs specialist clinics for people who are either training for new events they’ve never done before, so marathons, or for people who are taking exercise to the next level, either semi-elite to elite or champions, and give them advice about how to manage their diabetes when they’re exercising.  Dr Andrews is already one of the leading experts on Type 1 Diabetes and exercise and to try and help, make sure he gives better and better advice every year, he leads of a team that do research to get that evidence to improve that is targeted to the specific needs of people with diabetes who want to participate in sports.

What is Aerobic Exercise?

Exercise that you can do for more than a minute or two is said to be aerobic.  Aerobic exercise includes sports like running for more than 400m, cycling, swimming.  Gardening, cleaning the car, or the house might be aerobic exercise and perhaps, like me, you have noticed that you have a low blood glucose level when you do some of these daily chores.  Dr Andrews says that during aerobic exercise it is common for blood glucose levels to drop quickly in people who have type 1 diabetes and in this video Dr Andrews shares some strategies on how to stop this from happening if you plan your exercise.

What will I learn?

Dr Andrews helps elite athletes and olympians who have type 1 diabetes to excel in sport, you may or may not be an elite athlete but you can be certain that you will get information that has helped people with diabetes to exercise safely at the highest levels on the planet.  With this video to learn some of the amazing secrets about diabetes and exercise that Dr Andrews shares with elite athletes.

Paul Coker was diagnosed with type 1 in 1977 and even with 40 years of experience of living with type 1 diabetes and he says that in this interview he learned new diabetes management tools.  If you or a loved one have type 1 diabetes that this video has lots of important tips and advice, even if you think that you do not exercise.

Be Part of the Research

Dr Andrews leads a team of researchers who define and explore exercise guidelines that other Doctors share with their patients around the world.  Dr Andrews is also a key member of the Exercise with Type One Diabetes (EXTOD) team.  EXTOD are looking for people, like you, who have type 1 diabetes who exercise or are thinking about exercising to take part in an important study.   Why not take part?  You can learn more about how you can take part in this study at the EXTOD website.

In this short video we’re going to be talking about how you manage your type 1 diabetes after aerobic exercise.  Dr. Andrews has already shared some of his incredible knowledge about managing type 1 diabetes before and during aerobic exercise in the previous two videos.  Dr Andrews will share the advice that he regularly gives to his patients but you should always consult with your own medical team before making changes to your diabetes care.


The Diabetes and Exercise Credit Card Analogy

Dr Andrews on a previous video you explained that exercising with diabetes is like spending money on a credit card, when you spend money on a credit card you must repay that debt later.  In the case of type 1 diabetes the fuel we spend when exercising is like money spent on a credit card, we must refuel later to prevent the consequences of an unpaid fuel debt, in this case a hypo during the recovery period.  Is that a good place for us to start exploring managing blood glucose levels in the recovery period?

There are two things that you have to think about when you’re finished your exercise. One of them is, how much energy you’ve burned and how you’re going to replenish that. The two reasons for replenishing is that one, I think people forget why you do the training. The reason why you’re doing the training is to increase your glycogen stores. You’ve got readily, easier glucose available. That means, because, glucose is the best thing to burn when you’re doing exercise, that you can run faster and longer. The more you have a build up of that then the faster and longer you can run. In order to build that up you need to eat because you’ve burnt it. What happens after you finish the exercises, the body signals and says, “I actually did lots of work, I want to store more.” You only get an hour afterwards in order to increase those stores. If you don’t eat within an hour after exercise, you don’t get the benefits of increasing your glycogen from training.

We quite often see that with the patients who say “I’ve had a ceiling effect since I’ve got diabetes. Actually, I’ve had a ceiling effect, my times don’t get better and everyone else I train with, they get better.” The main problem there is you’re not eating within the hour and eating the right things. That’s why dieticians are really important. If you said to me what’s the things to eat afterwards? What you need to be doing is eating in a ratio or four to one, four carbohydrates to one protein. The ideal kind of things are milkshakes, things like that afterwards. So it’s nutrition, thinking about how you’re going to get back.

The other thing you’ve got to think about is, how have I affected the way my insulin works? We know that when you do an exercise that you become my sensitive to that insulin. There’s two ways of managing that increased sensitivity. One of them is that you reduce the amount of insulin you’re going to take over the period afterwards. Or, you say, I don’t want to reduce that because actually I want to build up my thing so you have to have more calories. You’re having more calories per amount of insulin so you have to eat more.

Speaking as a runner with type 1 diabetes my personal experience is that my blood glucose levels drop 8 to 10 hours after I go for a jog, is this common in people with type 1 diabetes?

Yes that’s really common. What happens is that your hormones that protect you and try to push up your glucose go up during the exercise. Then they stay up for six hours afterwards. To help the remodelling, to help you to get the glucose back into the right places and build up your glycogen stores. Then at six to eight hours, they fall away. At that point, you get all the effect of the exercise on your insulin sensitivity. From six hours onwards is the likely point when your glucose is likely to fall.

How can we manage this fall in blood glucose levels?

You’ve got two ways of managing that. One is that you have to eat quite frequently and to kind of snack to keep that up. Part of that is what we talked about with the credit card is, is the body asking for more calories back again. Or, the other way that you can do is reduce your insulin.

We know that there is a high risk of hypoglycaemia 8 to 12 hours after aerobic exercise, do you have any advice on how we might prevent night time hypos if we exercise in the evening?

We say to our patients that you have a choice, it’s a reduction in insulin or, it’s have some food. You’ve got a choice. Again, that depends on what’s happening with your body weight and whether you’re trying to build muscle or body mass or whether you’re trying to lose weight. If you don’t want to reduce the insulin then what you need to have is a carbohydrate with some protein. The protein makes the carbohydrate last much longer overnight and that’s what you’re wanting to do. If you said what trails have there been? The things that have been found in trial are Special K, so cereal, milk, or porridge, are the two things that tend to help.

It’s worth mentioning that unfortunately, the blood sugar that you have before you go to bed is not predictive as to whether you are going to have a low in the night. There is no correlation. If it’s 10, it doesn’t mean lower chances of a low.  If it’s something that is new to you, or something that’s been really quite intense, there’s no other way around, unless you’ve got continuous glucose monitoring (CGM) you’ve got to set the alarm clock and check it at 2:00 and check it at 5:00.

Following on from a late afternoon or early evening aerobic exercise session I test my blood glucose level before I go to bed and it is 10mmols/l (180mg/dl), should I think about correcting that?

We would suggest to our patients that they don’t correct at 10mmols/l. What we tend to say is add four to your correction starting point. If you normally would’ve correct at 10, don’t correct to your 14, give yourself a bit of space that the correction isn’t going to make your blood glucose fall overnight.


What would be your key message to people in terms of managing their diabetes after aerobic exercise?

Blood glucose testing is king. Make sure that you monitor the blood sugar afterward, particularly overnight especially if you’ve done events that you haven’t done before, or intense events.

Recording of those results and what was actually happening on that day, during that exercise session, what the weather was like, what you’d eaten and actually and how you felt on the event provide a useful reference for planning your next exercise session.

How you feel during an exercise session can be an important factor

There’s something called the Borg Scale, which tells you how hard it was. One of the prime thing that we get from people is that many runners always do the same run, they like the same run. They say, one time I do the run and my blood sugars go down. Another time I do the runs and they go up. I do exactly the same time of day, why is that? If you are a runner you’ll know that occasionally you have good days and occasionally you have bad days. You have a day when you’re flying and it’s very easy. If you’re flying and it’s very easy then you’re not stressed. You don’t produce the stress hormones. You have other days when it actually is tough. When it’s tough, you produce the stress hormones so you blood sugars tend to go up. If you keep a record of how hard it was then you get an idea of what where your blood glucose goes, depending on how hard it is. In the event, if you’re doing cycling or a long event, then you know what’s happening to your blood sugar at each of those time points.

Thank you, Dr. Andrews, you’ve shared some incredible insights in these three videos about aerobic exercise. In the next videos we’re going to be talking about anaerobic exercise and how that’s different from aerobic exercise and what changes and challenges that presents to managing diabetes. Thank you very much and we’ll see you on the next video.