Hello. I'm recently diagnosed with type 2 and everything I read tells me that exercise is good for me and will help lower my BG levels. However, my experience since being diagnosed is that whenever I go for a run (I don't run that far - yet 🙂) and test my levels afterwards, it seems to have gone up rather than down. Why is that?
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Post-Exercise Spike
- Thread starter melbs
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The impact of exercise on BG has to be viewed in shorter and longer time scales.
It is usual for BG to lower over the 24 hours after exercise but the impact during and immediately after can vary depending upon the type of exercise, the length of exercise and your "comfort" during the exercise.
Typically, cardio lowers BG but resistance training raises it.
However, you need to exercise for at least 20 minutes to see this impact.
And then it comes down to your fitness and comfort. If you are very fit, you will need to do more intensive exercise for an impact. If you find the exercise stressful, it will raise your BG. This could be down to pushing yourself too hard, wearing uncomfortable shoes or even the weather.
I can illustrate this through my experience. I exercise most days so consider myself reasonably fit. Although the types of exercise I do vary from climbing to running to weights, I think the impact of my BG when doing different types of cycling is clearest:
- if I pootle along a flat canal tow path whilst chatting to my friends, my BG is unaffected.
- if I do a full on Spin class for 45 minutes, my BG plummets
- if I cycle up a steep hill in the rain against the wind whilst wearing non-waterproof clothing, my BG rockets
But, whichever I do, my insulin sensitivity improves over the next 24 hours.
It is usual for BG to lower over the 24 hours after exercise but the impact during and immediately after can vary depending upon the type of exercise, the length of exercise and your "comfort" during the exercise.
Typically, cardio lowers BG but resistance training raises it.
However, you need to exercise for at least 20 minutes to see this impact.
And then it comes down to your fitness and comfort. If you are very fit, you will need to do more intensive exercise for an impact. If you find the exercise stressful, it will raise your BG. This could be down to pushing yourself too hard, wearing uncomfortable shoes or even the weather.
I can illustrate this through my experience. I exercise most days so consider myself reasonably fit. Although the types of exercise I do vary from climbing to running to weights, I think the impact of my BG when doing different types of cycling is clearest:
- if I pootle along a flat canal tow path whilst chatting to my friends, my BG is unaffected.
- if I do a full on Spin class for 45 minutes, my BG plummets
- if I cycle up a steep hill in the rain against the wind whilst wearing non-waterproof clothing, my BG rockets
But, whichever I do, my insulin sensitivity improves over the next 24 hours.
PerSpinasAdAstra
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As far as I can make out it's due to hormones released in response to the exercise - primarily cortisol and adrenaline. If the exercise is 'stressful' to the body the hormones will cause BG to increase, if not the hormone release is minimal and BG will go down.
In my case if I go for a brisk walk starting around 30 to 45 minutes after eating the exercise reduces my BG at a time when it would otherwise spike due to the carbs in the meal. If I lift weights it goes up for a while. I'm not fit enough to run (yet 😉 ).
As @helli points out though there is a lasting effect due to improved insulin sensitivity in muscle tissue whatever kind of exercise you do. I have not observed that directly myself though science and the long experience of others says it's there.
If your exercise level reaches a point of stress you will release counter-regulatory hormones such as cortisol. It's temporary and you'll still see eventual BG lowering over time for two reasons: Exercise isn't free; you used glucose, and secondly, over time the exercise will make you more insulin sensitive. That can last roughly 24 hours. If you simply walk, and do so at a slower rate, you may be able to get underneath your stress level and lower glucose without a short term reaction, but I wouldn't sweat it either way. One more thing: I believe you're more likely to see this BG spike in the morning because that is when counter-regulatory hormones are at their peak, and as a TB2 your pancreas may well not be producing an optimal level of insulin in the first place. In short the cortisol and others are shouting down your insulin and your liver isn't getting the message to stop. I find that exercise late in the afternoon and early evening offers me the greatest BG lowering. That said, I now walk 3 hours a day (20000) steps, and I've found that my BG levels can't ignore that much exercise no matter when it is done.
Pam123
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- Type 2
I have recently gone back to the gym and to begin with I notice using the machines and weights my BS would rise then after the session either legs or arms i would do cardio and it would drop really quickly, I have noticed now with doing this 5 days a week usually one hour sessions and up to now 15 minuites are keeping my BS levels really stable, I also go to the Gym in the afternoon
Pam123
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My PT is T1 and he told me the weight training and resistance work would make your BG go up, and cardio lowers it, I cannot walk very far due to my mobility problems, but something like the rowing machine and bike at the gym works a treat.
I've heard weight lifters on youtube claim that building muscle mass is an important thing for people with diabetes...1 or 2 since your skeletal muscle has more than 3x the capacity to absorb glucose than the liver.
I do not understand how this helps someone with Type 1 where our problem is not excess glucose but insufficient insulin which we overcome through injecting insulin.
Whilst there is a certain level of logic in this, it is not the full picture.
I tend to think of it as stop/start exercise and anything which stresses your body tends to increase BG whereas as constant exercise will reduce it.
However, there are still nuances in that based around fitness. As I am quite fit, a gentle stroll does not lower (or raise) my BG.
This is best illustrated with my experience of cycling
- if I pootle along the flat canal; tow path chatting to my mates, my BG is barely affected
- if I do a full throttle 45 minute Spin class (which I enjoy) my BG will plummet.
- if I churn my way slowly up a steep hill against the wind on a cold rainy day (which I hate), my BG will rocket.
Both the Spin class and the uphill are strenuous but I am not uncomfortably stressed during the Spin class.
Another type of exercise I do is climbing. This is short spurts of adrenaline inducing strenuous exercise. I enjoy it and the discomfort is very short lived. My BG will rocket.
As someone with Type 1, I am able to pre-empt the rises and falls through my insulin usage. So, if I get it right (which rarely happens) my BG is reasonably flat.
Doesn't the insufficiency of one lead to the excess of the other? The transport mechanism between bloodstream and skeletal muscle is not dependent on insulin. It uses it, but it has its own independent pathway. Therefore, an increase in muscle mass can assist in glucose control, and the skeletal muscle has a far greater capacity than the liver. An issue that I and many others with TB2 is sarcopenia, and resistance training can reverse it and lead to better glucose control.
That is good logic as far as it goes, and it's exactly the policy that I follow. However, I understand that there is another approach using short bursts of intense exercise, such as a series of sprints that can quickly deplete skeletal muscle reserves resulting in significant glucose control. It's strictly theoretical for me since I'm too old to sprint. However, I've been taking the approach that rust is a similar chemical process to fire, and so I walk 3 hours a day, which is roughly 20,000 steps. I don't know for sure if I'm tapping into my skeletal reserves, but I do know that after trying 10,000 steps a day, doubling it to 20,000 has allowed me much more control. I think it's the closest I can come to having a second pancreas.
No. Because we inject insulin, we do not have an excess of glucose. Therefore, we do not need to "store" glucose in our muscles.
Glucose control is through correct use of injected insulin.
In fact, exercise can make insulin dosing more complex.
I was referring to the natural state of a T1, not someone taking insulin. As for not needing to store glucose in your muscles, you're doing that every day of your life. The point of resistance training is to use the largest organ in your body to assist in glucose control, and while taking insulin is important for a T1 the notion that it obviates the need to be otherwise healthy doesn't make sense.
The "natural state of a T1, not someone taking insulin" is dead. Type 1 diabetes is an autoimmune condition which kills insulin producing beta cells. Insulin is necessary to live. So without "taking insulin" someone with Type 1 cannot survive.
I am not suggesting exercise of any sort is not a good idea. I am asking how resistance training helps glucose control for someone with Type 1 when it adds complexity to insulin dose calculations.
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I never suggested that T1's shouldn't take insulin, that is misdirection. My point is that resistance training helps with glucose control. Is the dose calculation more complex? Many T1 weight trainers on Youtube seem to think it's worth it. You don't. Fine.
I never said it is not worth it - I am a strong advocate of all exercise, regularly participating in cycling, hiking, running, climbing, resistance training and general gym workouts. I am questioning what you mean by "glucose control", especially with regards to Type 1 when we manage (with so much that can affect BG, I refuse to suggest we can "control" it) our blood glucose with insulin.
When we exercise, the amount of insulin we need (as you mention) changes which can make insulin doing more complex and lead to hypos when we get it wrong.
So, please explain, "what do you mean "helping glucose control" with regards to Type 1 diabetes (treated with injected insulin)?
Joining in here. I'm prediabetic which may help as my rise after exercise may be more limited. Many exercises like walking do lower it (thankfully, as a day hike would be interesting otherwise), but rock climbing really raises it. I started checking sugar because I was worried about climbing and my ability to belay safely after the dramatic diet I was put on combined with increase in exercise caused me to overdo my Calorie imbalance [medium-length story].
So maybe I'd learned again that the rope works (and the new belayer was good)? Maybe my insulin production had caught up and was balancing things?
Do I need to be concerned that exercise can have such a dramatic effect on sugar? (It seems so hard to talk to a doctor or specialist on this and my Oviva diabetes coach has been silent for about 6 weeks now - so I have no official channel to ask)
Thanks
- A high grade climb last night, top-rope, new belayer, fell a couple of times
shot up to 9.8mmol/l from my quiescent around 6 - Drank 500ml of water, rested a little
- Second high grade climb, familiar belayer, also took a couple of falls, but level dropping
- Level stayed more reasonable and recovered over the night (but climbing more in my comfort zone)
So maybe I'd learned again that the rope works (and the new belayer was good)? Maybe my insulin production had caught up and was balancing things?
Do I need to be concerned that exercise can have such a dramatic effect on sugar? (It seems so hard to talk to a doctor or specialist on this and my Oviva diabetes coach has been silent for about 6 weeks now - so I have no official channel to ask)
Thanks
Hi @RichardJC
Like you I am a climber. I to find that climbing raises my BG.
This is no surprise to me as there are a number of things associated with climbing which can push BG up
- when we start exercising, our liver will dump glucose to give us the extra energy we need. As we exercise for longer our bodies become more efficient in using that glucose. But as climbing is stop start, we do not reach the point of efficiency. The same is true for weights at the gym and HIIT.
- climbing, especially when we fall (or think we may fall) is stressful. Stress pushes our BG higher.
- climbing is an adrenaline fuelled sport. Adrenaline sends a message to our pancreas to halt insulin production. So, our BG rises.
Should you be concerned that your body's reaction to climbing is natural .. apart from the insulin resistance?
If it was me, I would be no more concerned than you are about having pre-diabetes.
Yes, your BG "shot up" to 9.8 (mine has been in double figures in the past until, as someone with Type 1, I learnt how to dose my insulin) but it came down.
It would be interesting to see the BG of someone with diabetes doing climbing. I suspect they too would have some spikes due to the stress and adrenaline.
The other thing to remember is, whilst some exercise like climbing will push our BG up, overall all exercise will lower BG in the longer term.
I certainly haven't give up climbing.
Like you I am a climber. I to find that climbing raises my BG.
This is no surprise to me as there are a number of things associated with climbing which can push BG up
- when we start exercising, our liver will dump glucose to give us the extra energy we need. As we exercise for longer our bodies become more efficient in using that glucose. But as climbing is stop start, we do not reach the point of efficiency. The same is true for weights at the gym and HIIT.
- climbing, especially when we fall (or think we may fall) is stressful. Stress pushes our BG higher.
- climbing is an adrenaline fuelled sport. Adrenaline sends a message to our pancreas to halt insulin production. So, our BG rises.
Should you be concerned that your body's reaction to climbing is natural .. apart from the insulin resistance?
If it was me, I would be no more concerned than you are about having pre-diabetes.
Yes, your BG "shot up" to 9.8 (mine has been in double figures in the past until, as someone with Type 1, I learnt how to dose my insulin) but it came down.
It would be interesting to see the BG of someone with diabetes doing climbing. I suspect they too would have some spikes due to the stress and adrenaline.
The other thing to remember is, whilst some exercise like climbing will push our BG up, overall all exercise will lower BG in the longer term.
I certainly haven't give up climbing.
Thanks. I certainly don't want to give up climbing 🙂
I know I also need to practice falling, especially lead falling, more.
Have you found you have to adapt to all the care that's asked about feet when you have diabetes? My climbing shoes are reasonably comfortable (though I'll have to try my old tighter ones again as I push my grade). But climbing is possibly hard on the feet. Of course I'm not affected by that at the moment and perhaps shouldn't worry too much about a future. (My doctor sees this as a progressive and inevitable disease, but I think I'm doing well at the moment).
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