Exercise and Blood Sugar: What They Didn’t Tell You at Diagnosis
You were told about carbs and insulin. Maybe even ratios. But exercise? Probably not.
Episode 755 of The Juicebox Podcast digs into what every person with type 1 diabetes discovers too late — that moving your body doesn’t follow one rule, and that the right kind of movement can send your blood sugar up or down depending on the type.
The Lesson No One Gives You
When you’re newly diagnosed, the list of “don’ts” is long. Exercise barely makes the list.
Doctors say, “Be careful.” But careful doesn’t mean informed.
Certified Diabetes Care and Education Specialist Jennifer Smith joins Scott Benner to explain why understanding exercise is as important as understanding insulin.
“It’s a neglected topic,” Jenny says. “You’re so busy learning everything else that movement ends up at the bottom of the list.”
And yet, it affects everything — timing, insulin needs, and safety.
Two Kinds of Exercise, Two Very Different Results
Scott jokes about “aerobic” versus “anaerobic” — running versus lifting — and Jenny laughs, but the truth behind it matters.
Aerobic (cardio) — running, biking, swimming, jumping on a trampoline — uses oxygen and tends to lower blood sugar.
Anaerobic (resistance) — weight training, sprints, heavy effort — triggers adrenaline and can raise blood sugar.
“The heavier the load,” Jenny explains, “the more adrenaline. That’s often what pushes numbers up.”Bold Beginnings 755
And real life rarely fits neatly into one category.
Your kid runs up and down the stairs 40 times after dinner — that’s aerobic.
But what if they also lift a heavy backpack? Now it’s both.
The Surprising Everyday Triggers
Exercise isn’t just the gym. It’s mowing the lawn, cleaning the house, chasing your dog, or walking through Target. Anything that raises your activity above baseline changes how your body uses insulin.
Scott sums it up:
“Your insulin settings are made for sitting at work or school — not for chasing kids or cleaning the garage.”Bold Beginnings 755
That means a “normal” day can suddenly become an exercise day — and if there’s active insulin on board, lows can hit fast.
Why Some Activities Make You Drop
Aerobic activity speeds up insulin use. If there’s a lot of active insulin, your body pulls glucose out of your blood faster — what Scott calls a “pull,” not a “drop.”Bold Beginnings 755
Fifteen to twenty minutes into cardio is the danger window. You might be fine at first, then suddenly sliding.
Jenny puts it simply:
“If you haven’t planned for it — no carb, no insulin adjustment — around 15 minutes is when it starts to nudge down.”Bold Beginnings 755
The Role of Adrenaline and Emotion
Here’s the twist: not all activity lowers blood sugar.
Competition and intensity can raise it.
A baseball game might spike you, while practice keeps you steady.
Why? Adrenaline.
“Games trigger excitement,” Jenny says. “That rush pushes glucose up.”Bold Beginnings 755
It’s not unpredictable — it’s physiology.
What Happens When Nobody Explains It
One listener wrote:
“My son was in baseball and swimming when he was diagnosed. The doctor told us he’d have to rethink his sports. I thought he couldn’t live a normal life.”Bold Beginnings 755
That kind of advice sticks — and it’s wrong.
People with type 1 diabetes run marathons, play in the NFL, and lift competitively.
Exercise isn’t off-limits. It just requires awareness.
Five Things That Make Exercise Work With Diabetes
Avoid aerobic exercise with active insulin on board.
If you just ate, wait. Active insulin + movement = rapid lows.Carry carbs — always.
Even quick, unplanned activity (like chasing kids) burns glucose fast.Plan for planned movement.
Lower basal before workouts or reduce meal boluses ahead of time.Expect adrenaline spikes.
Sports, lifting, or competition may raise glucose — you might even need a small bolus.Know your pattern, not just your number.
CGMs reveal whether you’re falling or steady; your response should match your trend.
What It Really Means
Exercise shouldn’t feel dangerous.
When you understand what’s happening — that movement changes how insulin behaves — you can stop guessing and start planning.
The goal isn’t avoiding activity; it’s owning it.
Listen to Bold Beginnings: Exercise (Episode 755) wherever you get podcasts, and learn how to make movement part of your diabetes toolkit — not something to fear.
References
Riddell MC et al. Exercise Management in Type 1 Diabetes: A Consensus Statement. Lancet Diabetes Endocrinol, 2017.
American Diabetes Association. Standards of Care in Diabetes 2025: Physical Activity.
Yardley JE et al. Managing Exercise in Type 1 Diabetes: Practical Strategies for the Real World. Diabetes Spectrum, 2020.
Misdiagnosed: Why So Many Adults Start Type 1 Diabetes With the Wrong Map
When adults are diagnosed with type 1 diabetes, the story too often starts in the wrong chapter.
They walk into a doctor’s office tired, thirsty, and scared, and walk out with a metformin prescription and a “Welcome to type 2” packet. Months—sometimes years—later, they discover they never had type 2 at all. They had type 1 the whole time.
I’ve heard this story more times than I can count on the Juicebox Podcast. Smart, responsible people, doing everything right, following the plan—and still running numbers so high you could fry an egg on them. They’re told they’re “non-compliant,” when in reality, they were never given the right tools for the job.
The Quiet Epidemic No One Talks About
Here’s what the research says: nearly than half of all new type 1 diagnoses actually happen in adults.¹ In some studies, as many as 4 in 10 adults with type 1 are first told they have type 2.²
That means thousands of people spend months chasing an answer that insulin could’ve solved on day one. Blood sugars climb, energy disappears, and people blame themselves for “failing” a treatment plan that was never meant for them.
Jenny Smith, CDE—my partner in the Bold Beginnings series—put it perfectly: adults with new-onset type 1 don’t get the same structured education kids do. There’s no hospital crash-course in carb ratios and correction factors. Most adults get a pamphlet and a pat on the back.
So they start managing diabetes with the wrong diagnosis, the wrong meds, and zero guidance. It’s like being handed a map of Spain when you’re trying to drive through Nebraska.
Why It Keeps Happening
Age Bias If you’re over 25, many doctors assume type 2 by default. They look at your birth date, not your antibodies.
Testing Gaps Most adults never get the GAD or C-peptide tests that prove autoimmunity. Without them, the diagnosis is guesswork.
Treatment Inertia Providers “start with metformin” even when insulin is clearly needed. Every extra month on the wrong med is another month of damage.
Language Barrier People hear words like basal, bolus, glycemic load, and think they’ve fallen into medical Scrabble.
And then there’s the human side. Imagine watching your blood sugar skyrocket after eating an apple, calling your doctor, and hearing, “You just need more exercise.” It’s maddening. By the time someone finally runs the right tests, the patient is exhausted, frustrated, and convinced they’re bad at this.
What Misdiagnosis Costs
It’s not just numbers on a meter—it’s trust.
Physically, prolonged high glucose levels can fast-track complications. Emotionally, it’s like fighting a battle blindfolded. Many people describe a period of guilt, of feeling “broken.” They weren’t. They were just holding the wrong instructions.
Even after the correct diagnosis, there’s fallout. People become wary of their doctors. They hesitate to ask questions. They second-guess every bit of advice. Rebuilding confidence takes time—and that’s where education comes in.
Fixing the System (and Yourself)
You can’t change how the healthcare system works overnight, but you can arm yourself with the right expectations.
1. Ask for Antibody Testing Immediately
If you’re newly diagnosed and things aren’t adding up, request these tests:
GAD65, IA-2, and ZnT8 antibody panels
C-peptide to measure natural insulin production
If your provider balks, remind them the ADA encourages clinicians to consider islet-autoantibody testing — especially in adults whose presentation doesn’t fit the usual type 2 pattern..
2. Question Age-Based Assumptions
Type 1 doesn’t “age out.” The immune system can flip at 8, 38, or 68. If your treatment isn’t working, it might not be you—it might be your diagnosis.
3. Get the Education You Deserve
Kids with new-onset diabetes get hours of training, dietitians, and nurses who walk them through every beep of a pump. Adults get a handshake.
That gap is why we built Bold Beginnings—to give grown-ups the same foundation kids get, just without the hospital gown.
4. Find Your Language
Understanding terms like basal, bolus, correction factor, and time in range isn’t about memorizing jargon—it’s about speaking the language of your own care. Once you can name what’s happening, you can manage it. (And if those words still sound foreign, you’ll love our next piece: Foundations—Learning the Language of Diabetes.)
5. Don’t Be Afraid to Start Over
Getting re-diagnosed as type 1 can feel like failure. It’s not. It’s the moment the fog lifts.
The day insulin enters the story is usually the day the story starts making sense.
What It Really Means
Every week, more adults are diagnosed with autoimmune diabetes. Some will get the right answer quickly; many won’t.
But here’s the truth: you can’t manage what you don’t understand—and you can’t understand what you’ve never been taught.
That’s what Bold Beginnings is for. It’s the foundation class everyone should get on day one. It’s where Jenny and I break down the big words, the scary numbers, and the guilt that sneaks in between them.
If you’re newly diagnosed—or newly correctly diagnosed—start there.
Because once you have the right map, the road ahead may still twist and turn, but at least you’ll know where you’re going.
References
Thomas NJ et al. The Diabetologia Study on Adult-Onset Type 1 Diabetes Misclassification. 2020.
Davis AK et al. Clinical Features and Diagnosis of Latent Autoimmune Diabetes in Adults (LADA). Diabetes Care, 2019.
American Diabetes Association. Standards of Care in Diabetes – 2025.
Leftover Pasta Is Easier On Your Blood Sugar
Ever heard someone say leftover pasta is “better” for blood sugar than freshly made? It’s not just a myth—there’s real science behind it, though with some caveats.
Freshly Cooked Pasta: Fast Energy
Cooking gelatinizes the starch in pasta, making it easier for digestive enzymes to break it down into glucose. That can lead to a sharper post-meal blood sugar rise.
The Cool-Down Trick
When you refrigerate cooked pasta, some of the starch undergoes retrogradation: the molecules realign into a more crystalline structure that is harder for your body to digest. That portion is called resistant starch (RS3), which behaves more like fiber.
Glycemic Impact
Because part of the starch is “protected,” digestion and absorption slow down. In many starchy foods (rice, potatoes), this cooling step lowers the post-meal glycemic rise. While less research exists for pasta specifically, the mechanism likely applies.
What About Reheating?
Reheating doesn’t erase all the resistant starch. Much of it survives moderate reheating, so you still retain some of the glycemic benefit — though very high heat or long reheating may reduce it a bit.
Takeaways
🍝 Cook → cool gives you resistant starch.
❄️ Cooling pasta helps lower its glycemic impact.
🔥 Gentle reheating preserves most of the benefit.
💡 This effect is known to work in rice and potatoes; for pasta the evidence is more limited, though plausible.
Let’s Take a Deeper Look
1. Starch Structure and Digestion Pasta (and other starchy foods) is made up of two main starch molecules: amylose and amylopectin. When pasta is freshly cooked, the starch molecules are in a gelatinized, more open form, making them easy for digestive enzymes to break down into glucose. This leads to a higher glycemic response (faster rise in blood sugar).
2. Retrogradation (Cooling Effect) When cooked pasta is cooled in the refrigerator, the starch molecules undergo a process called retrogradation. During retrogradation, the gelatinized starch chains recrystallize into a more compact structure. This transformation creates resistant starch—a form of starch that resists digestion in the small intestine.
3. Resistant Starch and Blood Sugar Because resistant starch isn’t broken down into glucose in the small intestine, it behaves more like fiber. It passes into the large intestine, where it feeds beneficial gut bacteria instead of spiking blood sugar. The result is a lower glycemic impact: blood glucose rises more slowly and steadily after eating cooled pasta compared to freshly cooked pasta.
4. Reheating Pasta Interestingly, if you reheat the refrigerated pasta, much of the resistant starch remains intact. So reheated pasta often still has a lower glycemic impact compared to eating it fresh.
✅ Takeaway: Cooking → cooling → (optional reheating) changes part of the pasta’s starch into resistant starch, lowering its glycemic index and making it friendlier for blood sugar control.
Skip the Struggle: A Guide to Type 1 Diabetes
Why the Standard Info Leaves Gaps
When you’re first diagnosed, you’ll hear things like:
“Pre-bolus 15 minutes before eating.”
Pre-bolus timing actually depends on the type of insulin and the meal. For most rapid-acting insulins (aspart/lispro), 10–20 minutes often works well; for ultra-rapid options (faster aspart/Lyumjev), 0–10 minutes may be enough. Shorten or skip if you’re trending low, eating low-GI foods, or don’t know the carbs yet.“Don’t stack your insulin.”
Avoid blind corrections during your insulin’s active window unless you’ve accounted for insulin-on-board (IOB) and have a clear reason — like a rising CGM trend, missed carbs, or a delayed spike from a high-fat meal.“Better to be a little high than risk going low.”
Preventing severe lows is essential, but running high most of the time isn’t the goal. Work with your team on targets that keep you safe and improve time-in-range. Wider targets can be fine while you’re learning.
These are rules — and they’re well-intentioned — but they’re not the whole picture.
Here’s what’s missing:
Why timing matters and how to adjust it for different foods.
When “stacking” is actually the right thing to do — and how to do it safely.
How to read patterns, not just numbers, so you can act early instead of chasing highs and lows.
How to connect all the moving parts — basal rates, meal timing, correction factors, fat/protein impact, exercise, stress.
You’re left with puzzle pieces… and no picture on the box.
What Happens When You Rely Only on the Basics
If you follow only the generic rules, a few things often happen:
You get frustrated because your numbers bounce around despite “doing it right.”
You play it safe by keeping blood sugars higher than they need to be — just to avoid going low.
You feel stuck, unsure how to make adjustments without “breaking” something else.
You may start to think… “Maybe this is just what life with type 1 looks like.”
It’s not.
What You Really Need: Principles, Not Just Rules
Rules are rigid. Principles are flexible.
Principles give you the “why” so you can adapt to any situation.
Examples from real-world, lived experience with type 1:
“It’s not stacking if you need it — that’s bolusing.”
You can safely give more insulin if your body still needs it and you’ve considered IOB.“Timing and amount.”
Every blood sugar result comes down to using the right amount of insulin at the right time. Master these two levers and everything gets easier.“Trust what you know is going to happen.”
Once you’ve seen a pattern several times — a food spike, a post-exercise low — you can act early. Confirm with CGM trends and IOB to avoid being tricked by sensor lag or false lows.
The Power of Learning From Lived Experience
When you combine solid medical knowledge with lived experience, you get:
Context: The difference between theory and how it actually plays out.
Pattern recognition: How to spot what’s really causing that high or low.
Confidence: The ability to make adjustments without fear.
It’s like the difference between being handed a map with a red dot that says “You are here”… and walking alongside someone who’s already made the trip dozens of times, pointing out every shortcut and hidden hazard along the way.
You Can Shorten the Hard Part
You don’t need to spend years reinventing the wheel.
That’s why resources like the Sips with Jenny conversations exist — to give you:
The missing explanations behind common advice.
The real-world scenarios so you can recognize them in your own life.
The mental tools to adapt to any variable.
Type 1 diabetes will never be “easy.” But you can get so practiced at it that it feels easier — much sooner than you think.
If you’ve just been diagnosed, the most important thing you can do is start learning from people who’ve already solved the problems you’re about to face.
It’s not about replacing your doctor. It’s about adding lived experience to your toolbox so you can turn rules into skills.
You’re at the very start of your journey. The sooner you understand the why behind the numbers, the sooner you’ll stop feeling like diabetes is running the show.
🛠 Real-World T1D Quick Tips + Where to Learn More
⏱ Pre-bolus timing
Rapid-acting (aspart/lispro): 10–20 min before eating.
Ultra-rapid (faster aspart/Lyumjev): 0–10 min.
Shorten/skip if trending low, eating low-GI, or unsure of carbs.
➕ Stacking vs. bolusing
Stacking = giving insulin without considering insulin-on-board (IOB).
Bolusing again can be safe if:
CGM shows a rise with arrows,
carbs were missed or underestimated,
a high-fat meal is spiking you hours later.
Use pump/app IOB tracking to avoid overdoing it.
🥓 Fat & protein impact
High-fat/high-protein meals can cause a delayed rise 2–6 hrs later.
Options: split bolus, extended/square wave bolus, or a planned follow-up dose (account for IOB).
🏃 Exercise effects
Easy aerobic → often lowers glucose (may need temp basal/less bolus or carbs).
Sprints/HIIT → can cause a short-term spike (sometimes need correction after, not before).
💡 Trust patterns — with proof
Act early on a pattern you’ve seen repeatedly and confirmed with CGM + IOB.
Watch for CGM lag or compression lows before treating.
🎯 Learn Faster, Skip the Guesswork
The Bold Beginnings, Pro Tip, and Small Sips series on the Juicebox Podcast walk you through these principles — and many more — with clear explanations and real-life examples.
📌 Start here: JuiceboxPodcast.com/lists
MISSING PERSON
I have difficult news to share about a member of the private Juicebox group - Juicebox Podcast: Type 1 Diabetes
Lucien Vink, age 51, has been missing since Sunday, July 6, 2025. He was last seen in the Rancho Mission Viejo area of San Clemente, California, near Camino Forestal and Calle Precipicio, wearing a dark short-sleeve T-shirt, dark shorts, and carrying a black backpack.
Lucien is a type 1 who left home without his diabetes supplies. He has not contacted family or friends since that date, and authorities are deeply concerned for his safety.
Local residents have been asked to review surveillance footage from July 6, including doorbell or security cameras, for any potential clues.
Authorities encourage anyone with potential sightings or helpful information to contact the Orange County Sheriff’s Department at 714‑647‑7000 or to call 911 directly in urgent cases. Even seemingly minor details can be incredibly important.
Here’s a post Lucien shared in the Juicebox community, highlighting his strength and optimism in managing his diabetes:
"Joined the group in Feb this year, after my DX in July 22. After DX I tried, got on Dex and OP5 pretty quickly, but had 1 scary low event and kinda rode around a ‘comfortable’ 160-200 for a while. When I found this page, read many posts and listened to a bunch of podcasts, I decided to make a change with an eye on long-term effects, and be more bold and less scared of insulin. HA1c was upper 12’s at DX (had all the signs for months, ignored them, but saw the doc after realized I had lost 25lbs on a frame that had no lbs to lose in the first place), HA1c was 6.7 in Oct, and now came back today at 5.3!! Thank you Bold With Insulin and everyone here, you’ve been a humongous help and support!
PS, did not even make huge changes in lifestyle, we eat moderately healthy, still eat out quite frequently, drink here and there, but are more responsible in choices of food and drinks. Tweaked some OP settings, have been running mostly in manual for last 3 months, taking advantage of extended boluses and temp basal rates, and generally being more bold; nudge&bump, and crush&catch if needed. Once you have your brain wrapped around that it’s easier to catch a low, than bring down a high, it becomes pretty natural."
Please hold Lucien and his family in your thoughts and prayers.
Dateline Article can be found here - https://www.nbcnews.com/dateline/missing-in-america/lucien-vink-california-missing-person-rcna221559