Increase in fasting blood glucose after exercise

This initial rise in BSL happens to me Ttoo, But I do not usually have drop until about 6 hours after.
I was told by my doctor that the release of adrenaline during exercise can raise the BSL because adrenaline causes the liver to release some stored glucose as part of an emergency response.
Why the drop later for me.? The explanation this time is that muscles have their own glucose supply, like an engine has a fuel tank. Exercise of muscles uses that glucose from the muscle (fuel tank) and later ? 2 hours but not sure but, 6 hours +/- the muscle demands refilling of its glucose storage ('tanks') from the supply line, the bloodstream. Of course that refilling can lower the BSL and cause the late hypos.
So management of exercise with those on insulin or other blood-sugar lowering medication needs to allow for these possible changes in BSL with exercise.
Two final things: I was told that when BSLs reach > 14 mmol/l, the liver actually releases glucose with exercise (some counter-intuitive body chemistry to do with such a BSL triggering a starvation response). So I do not exercise at that or higher BSls, only when the level has settled to nearer 11 mmol/.
Also of course exercising with a starting a low BSL may sound OK if the adrenaline is going to push the BSL up but can you balance and ride safely on a pushbike, run on roads or uneven surfaces with traffic etc, swim or handle weights safely AND be fit to drive to a gym when hypo etc? Please think again !!
Similarly adrenaline release I think is why I can experience high BSLS whilst and after watching a scary or exciting movie.
Finally when I experience a hypo, not only is glucagon released to cause release of stored glucose from the liver but the more general emergency signal (my brain gets tetchy if my blood glucose, its fuel, is in low quantity as during a hypo) is mediated by adrenaline which also influences the liver to release stored glucose.
I hope all this helps. I have not discussed how I might manage exercise, diet and medication-wise as I am unsure what your diabetes treatment is as a comparison. Best Wishes.

immasin said:

Hi, I usually have an increase in my blood glucose level after an exercise but about 2 hours later I will see significant drop. Any explanation please.

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What kind of exercise? It is said that exercise may raise or lower bg in some people according to whether it is aerobic or resistance training, gentle or intense. So far I have not caught my bg being affected by exercise, but perhaps when I experiment with a Libre I will learn more. You don't say either whether you are T1 or T2.

Hi immasin,

Do you have type 1 or type 2 diabetes? And are you on insulin? Pump or injections? All these things matter, it's complicated

I have T1D, on a basal bolus regime. I find that exercise normally lowers my blood glucose. If I eat appropriate carbs while exercising then I can keep bg levels steady unless I really push it and get my heart racing.

If I do that then I generate stress hormones, which prompt my liver to break down glycogen reserves at a greater rate than normal and dump glucose into the bloodstream. Without a matching insulin response this will raise bg levels, which is what you're seeing. If this is happening then you don't need to eat as much during this type of activity. As you get fitter this should happen less often.

But also, exercise uses up glycogen reserves in everyone, not just diabetics, and your body will try to rebuild those after the exercise ends, continuing to use up available glucose and lowering bg levels for some time afterwards. Getting a dip 2 hours afterwards sounds like this effect.

This makes it important to eat some medium to low GI carbs after exercise to prevent a dip. How much depends on the amount and type of exercise and the individual.

So... always eat carbs after strenuous activity. Nothing too sugary, and how much you'll need to figure out by trying different amounts and testing.

Good luck!

I see you're new, so tagging @daisy1 to provide the new members information which is very informative.

I'm not sure if I get a big rise immediately after exercise as I haven't ever tested before/after exercise. I only know that on exercise days my BG levels are a lot lower by the time I decide to eat. And I just take that as a good sign

This is normal, especially when we cross or get close to what's called the anaerobic or lactate threshold (approx 85% of HRMax). Our muscles start demanding instant energy in the form of glucose. When the BGL go low(ish). liver responds by dumping glucose reserves, but usually at much higher rate than the demand is (at the ratio of approx. 3:10). For a normal healthy person this is usually not a problem as the excess glucose will be dealt with a higher secretion of insulin. But diabetics usually have not enough insulin or are insulin resistant and the BGL go up temporarily for couple of hours.

Apparently, when in full ketosis, body switches from carbs based metabolism to fat/protein one. It never worked for me though. First of all, gluconeogenesis is a slow process, it takes much longer to metabolise protein and fat than carbs, and second, I was never truly in a full ketosis. The only thing that works for me is to eat small amount of carbs just before and immediately after hard exercise, just enough to fool the liver and stop it from dumping excessively. These days I mainly exercise in the evenings, approx 2 hours after the dinner so on the exercise days I also eat some carbs for a dinner, some potatoes, pasta etc. with a small fruit after the exercise. This seems to work well for me. My FBG levels are in low 5s. If I do not eat carbs, then I get 6+ in the following morning and the trend continues throughout the day...

@immasin

Hello Immasin and welcome to the Forum Here is the Basic Information we give to new members and I hope you will find it useful. Ask as many questions as you like and someone will be able to help.


BASIC INFORMATION FOR NEW MEMBERS

Diabetes is the general term to describe people who have blood that is sweeter than normal. A number of different types of diabetes exist.

A diagnosis of diabetes tends to be a big shock for most of us. It’s far from the end of the world though and on this forum you'll find well over 235,000 people who are demonstrating this.

On the forum we have found that with the number of new people being diagnosed with diabetes each day, sometimes the NHS is not being able to give all the advice it would perhaps like to deliver - particularly with regards to people with type 2 diabetes.

The role of carbohydrate

Carbohydrates are a factor in diabetes because they ultimately break down into sugar (glucose) within our blood. We then need enough insulin to either convert the blood sugar into energy for our body, or to store the blood sugar as body fat.

If the amount of carbohydrate we take in is more than our body’s own (or injected) insulin can cope with, then our blood sugar will rise.

The bad news

Research indicates that raised blood sugar levels over a period of years can lead to organ damage, commonly referred to as diabetic complications.

The good news

People on the forum here have shown that there is plenty of opportunity to keep blood sugar levels from going too high. It’s a daily task but it’s within our reach and it’s well worth the effort.

Controlling your carbs

The info below is primarily aimed at people with type 2 diabetes, however, it may also be of benefit for other types of diabetes as well.

There are two approaches to controlling your carbs:

• Reduce your carbohydrate intake
• Choose ‘better’ carbohydrates

Reduce your carbohydrates

A large number of people on this forum have chosen to reduce the amount of carbohydrates they eat as they have found this to be an effective way of improving (lowering) their blood sugar levels.

The carbohydrates which tend to have the most pronounced effect on blood sugar levels tend to be starchy carbohydrates such as rice, pasta, bread, potatoes and similar root vegetables, flour based products (pastry, cakes, biscuits, battered food etc) and certain fruits.

Choosing better carbohydrates

The low glycaemic index diet is often favoured by healthcare professionals but some people with diabetes find that low GI does not help their blood sugar enough and may wish to cut out these foods altogether.

Read more on carbohydrates and diabetes.

Over 145,000 people have taken part in the Low Carb Program - a 10 week structured education course that is helping people lose weight and reduce medication dependency by explaining the science behind carbs, insulin and GI.

Eating what works for you

Different people respond differently to different types of food. What works for one person may not work so well for another. The best way to see which foods are working for you is to test your blood sugar with a glucose meter.

To be able to see what effect a particular type of food or meal has on your blood sugar is to do a test before the meal and then test after the meal. A test 2 hours after the meal gives a good idea of how your body has reacted to the meal.

The blood sugar ranges recommended by NICE are as follows:

Blood glucose ranges for type 2 diabetes

• Before meals: 4 to 7 mmol/l
• 2 hours after meals: under 8.5 mmol/l

Blood glucose ranges for type 1 diabetes (adults)

• Before meals: 4 to 7 mmol/l
• 2 hours after meals: under 9 mmol/l

Blood glucose ranges for type 1 diabetes (children)

• Before meals: 4 to 8 mmol/l
• 2 hours after meals: under 10 mmol/l

However, those that are able to, may wish to keep blood sugar levels below the NICE after meal targets.

Access to blood glucose test strips

The NICE guidelines suggest that people newly diagnosed with type 2 diabetes should be offered:

• structured education to every person and/or their carer at and around the time of diagnosis, with annual reinforcement and review
• self-monitoring of plasma glucose to a person newly diagnosed with type 2 diabetes only as an integral part of his or her self-management education

Therefore both structured education and self-monitoring of blood glucose should be offered to people with type 2 diabetes. Read more on getting access to blood glucose testing supplies.

You may also be interested to read questions to ask at a diabetic clinic.

Note: This post has been edited from Sue/Ken's post to include up to date information.
Take part in Diabetes.co.uk digital education programs and improve your understanding. Most of these are free.

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MikeyU said:

This is normal, especially when we cross or get close to what's called the anaerobic or lactate threshold (approx 85% of HRMax). Our muscles start demanding instant energy in the form of glucose. When the BGL go low(ish). liver responds by dumping glucose reserves, but usually at much higher rate than the demand is (at the ratio of approx. 3:10). For a normal healthy person this is usually not a problem as the excess glucose will be dealt with a higher secretion of insulin. But diabetics usually have not enough insulin or are insulin resistant and the BGL go up temporarily for couple of hours.

Apparently, when in full ketosis, body switches from carbs based metabolism to fat/protein one. It never worked for me though. First of all, gluconeogenesis is a slow process, it takes much longer to metabolise protein and fat than carbs, and second, I was never truly in a full ketosis. The only thing that works for me is to eat small amount of carbs just before and immediately after hard exercise, just enough to fool the liver and stop it from dumping excessively. These days I mainly exercise in the evenings, approx 2 hours after the dinner so on the exercise days I also eat some carbs for a dinner, some potatoes, pasta etc. with a small fruit after the exercise. This seems to work well for me. My FBG levels are in low 5s. If I do not eat carbs, then I get 6+ in the following morning and the trend continues throughout the day...

Click to expand...

Really useful stuff Mikey thanks.