• Guest - w'd love to know what you think about the forum! Take the 2025 Survey »

Exercise doing more harm than good?

F

finzi1966

Well-Known Member
Messages
182

I need encouragement that exercising is the right thing to do!

I normally have a morning peak between about 8am -10am (up to 9-10mmol) and then by 11am it’s back to around 6-7mmol, and stays there for the rest of the day (I don’t really have peaks with food, cos I eat <5g carbs per meal)

Today I went to the gym (quite intense) at 10:30am and then did housework and a long walk and the only result seems to be that my blood has stayed at >9mmol all morning. That can’t be good, can it? That would never have happened if I’d just been sitting down, I can guarantee. I thought the damage was done by being “high” for long periods of time?

Reassure me that I’m not doing more harm than good!

(Type 2, metformin, forxiga and Ozempic)
 
Exercise does much the same to me.
This is from a quite strenuous cycle ride after just coffee+cream+butter.
As far as I know this is a liver dump which isn't used for immediate energy as I'm eating low carbohydrate and so running mainly on ketones.

 
There have been many threads about exercise and the two things that come out are that overall exercise is good (and not just for diabetes) but the immediate effect of exercise differs depending on the type of exercise, how fit you are and what your levels are when you start.
In general, prolonged cardio reduces levels and short stop-start exercise such as hit and weights cause levels to go up. But, if your body is stressed by the exercise, it will go up. For example, if I go for a long fast cycle ride along a flat road on a fair day, my levels will go down but if I cycle for as long up a steep hill against the wind during a rain storm, m levels will go up.
I also find that if my levels are higher than 8 (we all vary), cardio exercise will stress my body and cause my levels to go up.

The other thing to consider is that the reason our levels go up is that our liver is releasing glucose. The liver glucose stores need to be refilled and, as a result, even a big weight session will lead to a reduction in levels over the next 24 to 48 hours.

Finally, when damage is done by being high for long periods, a fe hours is not a long period. The damage is done over days, weeks, months, ...

In summary, unless you have injured yourself, exercise does not do harm but it is better to start with a lower level and you will see an immediate effect if you do prolonged cardio but intermittent and weights is also good longer term.
 
Thank you so much, that was really helpful. I thought by being really *intense* in the gym (well, intense for me - I’m not very fit!) I would “burn off” my morning glucose peak but it’s interesting that you say that if you start out the workout with higher levels, it makes them go up. I would describe what I did as cardio (elliptical machine and stationary bike, both done to max effort).

(It’s FINALLY dropped! 10.5 to 7.7 in a span of 20 minutes. Finished exercising about an hour ago.)
 
While in general I agree with @In Response , personally I don't want levels over 8.0 for any reason - even if they are depleting long term stores, which I doubt because from what I understand the liver can store only a small amount and it manufactures the rest from Protein and Fat (and fructose if it's available).

Thus when on a low carb, low fructose diet then higher BG levels due to strenuous rather than moderate exercise detracts for the benefit of that exercise so you may as well just exercise moderately in the first place. But the exception to that is if you are doing strenuous resistance exercise, in which case you are building muscle which will (in future) absorb an increasing amount of glucose from the bloodstream.
 
Interesting- I see what you mean. One conundrum (and I’m not expecting you to know the answer, just speculating) is that what is strenuous to me probably isn’t *truly* strenuous. I have congestive heart failure and multiple sclerosis, and I’ve lost a lot of muscle mass particularly in my legs since that diagnosis. So my “strenuous” is probably someone else’s “easy”.

(Eg in the gym I did 8 minutes on the elliptical machine and 5 minutes on the bike. I was very shaky afterwards).

I think maybe this “resistance” route is the way to go. I have ordered some dumbbells (1, 2 and 3kg). Is that what you would use for resistance? (I’m female btw)
 
"Strenuous" is a personal thing. If your heart is beating fast it is strenuous regardless whether it was a day climbing a Tour de France mountain or 5 minutes walking.
Unfortunately 8 and 5 minutes is long enough for your liver to notice the exercise and dump some glucose but not long enough for your muscles to become more efficient at using your insulin.
I am not a Personal Trainer or a doctor but wonder whether it would help if you tried a lower intensity workout. Maybe you can build it up over time.

Whatever you do, don't compare yourself with others - they have not been through your history or have your health conditions.
 
Mine does exactly the same, now 10 days post gliclazide mine seems to go up until I eat breakfast no matter what, when I go to the gym & lift heavy weights it rises then drops very quickly when I eat, if I go on the peleton after lunch though I don’t get any rise, just the drop
 

Sort of well documented exercise is good for everyone, diabetic or not.
Exercise can be of all sorts, for some people that is a fast walk or depending on need a slow walk for others that is hours on a treadmill.

What you might find is better on smoothing out BG spikes from intense exercise is longer but less intense.

Then over time as you get fitter you actually can do more at the same impact intensity as your fitness has improved.

It's the train to run slow to run fast. Spend 80% of your training at less than 80% max heart rate and your body will get fitter and you not creating the stress on your body.
 
Last edited:
Hi, I think that most of your questions have been answered by others, however I will just add a little:
1. Cardio exercise is good for all people (regardless of diabetes etc). But the NHS standard for that is a 30 min brisk walk 5 or more times per week. Now 'brisk' depends upon your level of fitness, so upon my discharge from hospital after my 3x Coronary Artery Bypass I could only manage a 5 min walk and although exhausting it wasn't what anybody would call brisk. When I was able to actually walk for 30min briskly, it was just a bit faster than a stroll - just enough to raise my heart rate and make me sufficiently short of breath that although I could talk, I couldn't sing while walking.
2. Any resistance exercise should be in addition to that 30 min five times per week brisk walk (or equivalent cycle, swim etc).

Certainly once I started to become fat adapted, I was able to halt my Dawn Phenomenon (high morning fasted BG ) in its tracks by having an approximately zero carb breakfast (boiled eggs). 2 hrs after that breakfast my BG was lower than before breakfast regardless of whether I'd had my daily walk or not.

Note that since I'm fully fat adapted I no longer feel hungry in the morning so now my first meal is a late lunch.
 

Did you eat anything pre gym?
 
I've tried not having the bullet resistant coffee before the ride.
I've also tried eating something low carbohydrate.
It doesn't seem to make much difference to my liver dump.

Cake at the coffee break to see if it gave me a boost is an experiment I will not repeat.
I hoped the steep drop which suggests plenty of insulin being released might cope with the sugary goodness.
Nope.
 
This is exactly what my endocrinologist told me.
 
My thought has always been that exercise, if it can be managed and is desired of course, is a good thing. It may cause short term spikes but I do feel that those spikes are very different to those caused by an overload of carbs and generally speaking, they do come down after a few hours. The long term effects are good for overall health and I exercise for all sorts of reasons, not just to manage or improve my diabetes. Bone health, heart health, mental health, strength, lung health, circulation and on and on, if improved by exercise must surely have a natural benefit when you have body that is 'flawed' in a way that can affect all those things and more. I know that it doesn't always have benefits dependent on individuals personal circumstances but I would say never be put off by rises in response to it, it's showing that your body is working hard! If you do it for long enough you will notice that as your body gets used to it, it stops responding in a panic. Then of course it becomes so easy to run 5 miles that you always start thinking you should shake it up a bit to get any further benefits!
 
You must log in or register to reply here.
Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn More.…