I am a type1 diabetic, wearing a G7 CGM. I do cycling, rowing, weights regularly accumulating to up to 10h/week. My normal gmi is around 5,8.
in June i caught pneumonia, which bothered me the whole summer. I could not do any sports until early September.
In these three months my average glucose went up by more than 2mmol or even more. My need for insuline went up by 2x/3x. Whereas usually my sugar would move around 5-6mmol, I would now be at 8-9mmol and had to inject lots of insuline to counter this. My overnight sugar level rose dramatically compared to normal times. Yes, parts of this is due to the pneumonia raging in my body. But mostly it was the lack of sports. My gmi rose to almost 7. My 1x Basal and 6-8 Bolus injections amounted to almost 50 units per day - a lot for me.
Since October I am back on my usual sports schedule mentioned above. My blood sugar dropped enormously by 2-3mmol in average and my gmi is moving back below 6. My need for insuline dropped again back to 1x Basal, 2-3x Bolus, amounting to roughly 15-20units per day.
Maybe not a scientific study but for me a strong indicator that sports, especially aerobic/ebdurance efforts, do very good things to your body.
As they say, everyone’s diabetes is unique, but my experience mirrors yours. I hate even ordinary rest weeks because they drive my numbers crazy. I need much higher basal doses and bolus ratio, and even then my averages are 20-50 mg/dl higher than normal. If I wind up with a reduced load for longer I can wrestle things back in control, but it’s work.
The reverse is true when returning to normal work levels. Glucose numbers plummet, and bolus in particular is difficult to get right. After a few days, things get back to normal. Maddening.
I think it’s most likely the boost in insulin sensitivity induced by exercise, and corresponding drop when exercise is reduced, particularly (for me anyway) reduced intensity.
I have found (thanks to the G7) I feel and perform best with elevated levels while on the bike. 150-170mg/dl is the sweet spot. When managed correctly, it drops to normal post prandial levels within 30-45 min of ending the ride.
T2 but nearly the same (G7). I’ll have an S-shaped pattern when I start, and it’ll settle around 140-150mg/dL, but depending on the effort, it might go higher. By the time I’m off the bike and showered, I’m < 130mg/dL.
Medical student here slaving over GI, Endocrine, and Nutrition which are required medical school concepts and are tested on comps, board exams, and on annual recertifications for any doctor who deals with metabolic health. While it’s true that docs are not dietitians able to personalize a regimen for you, we learn about the physiology of metabolism, blood sugar regulatory mechanisms including insulin, and nutrient uptake/balance/utilization in pretty exhaustive detail. As someone else has said, a given PCP will have treated thousands of patients with elevated blood sugar. Most importantly, the right doctor can identify any signs of a disease process, and the person qualified to rule those out for you is the person qualified to give you peace of mind. It’s likely that diet can bring down blood sugar for someone with your profile, @genefish, and should be considered first line alongside exercise. However, it is not always a relatively easy solution, contrary to what someone here has asserted. If your concerns remain after making diet changes, please see someone qualified to evaluate you.
There’s some good thinking and evidence in this thread, and I’ve learned some things, but there’s also a lot of anecdotal reasoning, speculation, and a handful of outright nonsense. Something that doesn’t seem to have come up here is that genetics are highly predisposing to T2 diabetes–different people don’t always respond uniformly to the same diet and exercise inputs. It’s very likely that your exercise has benefited your blood sugar profile, and that’s especially true if it turns out that you’re working against a genetic predisposition. Your numbers are cause to be prudent and preventive but not necessarily to worry.
Something like an oral glucose tolerance test would be a better indicator than your continuous monitor because conditions are better controlled and confounding variables are better excluded. Easy, painless, and gives much better information. You could approximate this by fasting overnight, consuming 75g glucose in water in the morning, and checking blood glucose after 2 hours, but lab grade equipment and expert guidance would be superior.
I’m in my late 60’s and was diagnosed with prediabetes last November. At my last blood test I had reduced my Hba1c out of the range by a combination of, using a CGM, walking for 20-30 mins after every meal and reducing considerably, what I called, my gratuitous carbs (cake, ice cream sweets etc) I’d fallen into the trap of thinking that because I rode my bike 15-20 hrs a week, I could eat what I wanted.
Looking at the graphs from my CGM it became evident that my night time and early morning glucose readings were low, my glucose spiked after every meal (shock, horror) and came down to baseline within a couple of hours and only remained elevated during the times I was doing long rides on my bike.
As I understand it measuring blood sugar to diagnose diabetes is a surrogate for measuring insulin, as insulin resistance is the real problem which causes the high glucose. Looking at the grapghs on the CGM and stripping out the periods in the day when I was riding and doing an eyeball calculation on the remaining time showed that my average glucose levels were fine outside of my riding. As I understand it my glucose is not be controlled by insulin during exercise, could this partly explain the diagnosis of pre diabetes and whilst i should be concerned there is perhaps no need to be paranoid about it.
As I’m in the UK its difficult to talk to my GP about it as a) He has no time for marginal things like this and b) Probably has no interest or real knowledge of the subject.
Jokes aside, whatever you do, don’t listen to someone diagnosing you on an internet forum or telling you to get medical advice from a podcast. They have no idea of the myriad health factors that could be at play here. A good primary care physician is well-trained to review literature on nutrition on top of the training they will have gotten in medical school.
Maybe in The States but I’d be surprised if the average GP here in the UK had more than a couple of hours of lectures on nutrition during his training. After that they just prescribe what NICE instructs them to. (National Institute for Health and Care Excellence) . The last word is a matter of opinion of course. Prediabetes - the advice I was given by the medical practice - Cut out the sugar and exercise more. If I had diabetes I’d just be put on drugs I suspect. The metabolic syndrome epidemic and the demands that are being made on the NHS appear to be overwhelming them.
Been doing my rides (2 hrs or less) fasted, we’ll see if that helps us blood sugar bros. Not saying it will improve my performance or any adaptations, but hopefully it does help my glucose.
I’m not going to dismiss a person who spent years in grad school studying every aspect of the human body, endocrinology, pharmacology, diseases, etc., and has years, possibly decades of clinical experience applying that knowledge with real flesh and blood humans. I’m certainly going to give my doc more credit than someone with a youtube video.
I do reserve the right to occasionally disagree or seek out a doc who has a better background in a specific problem, but to think they don’t know anything about nutrition is to dramatically misunderstand how learning occurs or how med school works.
Just remember that it doesn’t have to be all or nothing. There are slower sources of carbs that won’t spike your bg as much as other sources, and “when” you eat carbs will also affect your bg, also. I don’t have any issue doing a 2 hr zone 2 ride fasted, but if I weren’t trying to lose weight, I’d still need to fuel that 1200+ calorie effort and there are better ways to fill that calorie deficit (without detriment to A1c) than eating a piece of cake or chips and dip at 9pm.
Yeah, 600 cal/hr is z1 for me, but I didn’t want to be presumptuous about Shisheveudysgj.
Higher wattages do give some headroom for increased weight loss, particularly since it should be more fat (than carbs) burned in zone 1 and 2. Also means the carb fuel burns it faster in the higher zones. Unfortunately, I’ve been fueling like a TDR participant, while riding like a 2nd year cyclist for the last half-dozen years, so for me, my burn rate has finally caught up to my diet, lol.
I don’t know. A good friend of mine is a recently retired GP who used to regularly put people on 1000kCal diets to loose weight. It was rarely successful because " the patients showed no will power". He’s a good friend but I’m glad he wasn’t my GP.
Granted the newer cohort of GPs coming through probably have more knowledge of nutrition because we now realise how important it is . A lot of the older ones won’t have kept up with the modern thinking and had very little training on nutrition 40 years ago
