Exercise as support: which movement does what for blood sugar

Why movement works so strongly at all

The core is quickly explained: working muscles need energy – and take glucose from the blood. What’s special: during exertion the muscles can take up sugar even without insulin. For this they move a transporter called GLUT4 to the cell surface, entirely independent of how well insulin is currently working.¹ That’s exactly why movement is so valuable with insulin resistance: it opens a second route for sugar to get from the blood into the cells.

On top of that comes the long-term effect: regular training makes the cells more sensitive to insulin again. The body needs less of it to do the same job – the baseline load drops. So movement lowers the value short-term and improves the whole regulation long-term.

1. Moderate endurance – my most reliable lowerer

Evidence level: established (mechanism) + n=1

Easy cycling, brisk walking, calm swimming – anything that brings the pulse into a comfortable “I could still hold a conversation” zone (roughly zone 2). For me this is the most reliable way to actively lower blood sugar. At this intensity the muscle continuously burns glucose without the body strongly releasing stress hormones that would counteract it.

How I do it: in the morning I ride 30–45 minutes on the Peloton at a calm intensity. That’s the core of my routine – and in my long-term documentation my pattern shows clearly: moderate endurance reliably lowers for me, while intense effort tends to raise. How a single such session starts on an empty stomach I document in Protein fasting & blood sugar.

2. Very intense – can briefly raise the value

Evidence level: established (mechanism) + n=1

This surprises many: after a hard session – intense intervals, maximum effort – blood sugar can briefly rise instead of fall. The reason is stress hormones (adrenaline, cortisol): they signal the liver to release extra glucose into the blood so the muscles have enough fuel under full load. Only afterwards, when the body recovers and refills its stores, does the value fall – often even below the starting point.

I see this biphasic curve (“down first or straight up, then down”) in my data again and again. A Peloton evening swings up and down several times after the sessions for me – here the value stayed within the target range:

I experience the same principle with stress-intensive firefighting call-outs: even without a bite of food my value rises, purely from the tension and strain. That’s no reason to avoid intense movement – on the contrary, it has its place. You just have to read the short-term rise correctly and not panic. I’ve broken down the full curve in Exercise: down first, then up.

3. Strength training – the lever for the long game

Evidence level: established

Strength works less via the single, acute effect, but all the more over time. The reason: muscle is the body’s largest sugar store. The more muscle mass you have, the more storage space for glucose is available – and the better your body responds to insulin. That’s why especially the large muscle groups (legs, back) are so valuable.

How I do it: alongside cycling I go to the weights several times a week, with a rotating split and deliberately an extra leg day – the thighs in particular are decisive for glucose uptake. Strength is the investment you don’t see immediately in the day’s curve, but months later in the HbA1c.

4. Everyday movement – the underrated weapon

Evidence level: established

You don’t always have to “do sport”. Perhaps the most effective everyday lever is the walk after eating. The evidence is clear: even 10–15 minutes of walking shortly after the meal noticeably lower the blood-sugar peak – depending on the study and meal by around 20 to 50 percent.² Three short walks after the main meals measurably improve blood-sugar control across the whole day – partly better than a single longer walk.³

I experience this myself too: during a week when my morning cycling was replaced by about a kilometre of walking (a trade-fair week), my curve still stayed calm – everyday movement catches a lot. The effect comes exactly via the insulin-independent route above: the muscles grab the sugar right as it comes from the meal.

How much does it really help? My curve over 90 days

Evidence level: single-case observation (n=1)

Now to the question that matters most: how strongly can movement really bring the metabolism back? I can’t promise a universal figure – but I can show you my documented values. Over about 90 days of consistent movement (plus adjusted nutrition), the following shifted for me:

And this matches the evidence: those who move at least 150 minutes per week and lose weight moderately (about 5–7%) can markedly delay or prevent progression to type 2 diabetes.⁴ Movement is thus one of the most effective non-drug levers we have.

If I were starting from zero

You don’t have to do everything at once. If I were starting from zero today, this would be my order:

• Week 1–2: after every big meal, walk 10–15 minutes. The simplest, most effective first step.
• Week 3–4: add 20–30 minutes of easy endurance on several days (bike, brisk walking).
• From week 5: add strength for the large muscle groups 2× per week.
• Throughout: look at your own CGM curve instead of other people’s promises – it shows you what works for you.

The most important factor isn’t the perfect session, but the regularity. Small things, every day, beat the big effort every two weeks.