Exercise for type 2 diabetes: what to do and how much

When somebody with type 2 diabetes tells me they have "no time for the gym", they are almost always thinking of the wrong exercise. What lowers your glucose is not suffering for an hour: it is doing the specific things that make your muscle ask for sugar.

Why muscle is the key

Your muscle is by far the biggest consumer of glucose in your body. And it has an extraordinary property: when it contracts, it can take up glucose without needing as much insulin. It opens an alternative door.

From that come the two practical consequences of this whole article:

• Moving muscle lowers glucose right now, during and after the effort.
• Having more muscle lowers your glucose permanently, because you have more places to put it.

That is why losing weight by losing muscle is a bad metabolic deal: you get thinner and end up with less capacity to handle sugar.

How much is needed, according to the guidelines

150 weekly minutes is a little over 20 minutes a day. Or half an hour, five days. Add two 25-minute strength sessions and you are already meeting the full recommendation.

Which exercise, in order of return

1. Strength — the one that changes the underlying problem

It is the great absentee from the advice most people receive, and probably the most profitable. It builds the tissue that consumes glucose.

You need no gym and no weights. Sitting down to a chair and standing back up, pushing against a wall or doing incline press-ups, rowing with an elastic band, climbing stairs, calf raises. Two or three days a week, not back to back.

2. The ten minutes after eating

The moment of highest circulating glucose is after a meal. If you move muscle right then, it takes it away. Ten or fifteen minutes walking after your main meal is probably the best return per minute invested in this whole field.

3. Sustained aerobic work

Brisk walking, cycling, swimming, dancing. Moderate intensity means you can talk but not sing. You do not need to run: if you have not run in twenty years, starting by running is the fastest way to get injured and quit.

4. Breaking up sitting

It does not look like exercise and it counts. In people with type 2 diabetes, breaking up sitting with three minutes of walking every half hour lowers glucose after meals. If you work sitting down, it adds to whatever training you already do.

To start with, sitting down on a chair and standing up again is enough: what counts is that the muscle works.

If you take medication, read this

Other situations worth checking first: advanced retinopathy (some very intense efforts may be inadvisable), neuropathy in the feet — check them daily and mind your footwear — and any known heart condition. None is a reason not to move. All are a reason to choose carefully how.

A starting plan for somebody doing nothing today

1. Weeks 1–2: 10 minutes walking after your main meal. Every day. Nothing else.
2. Weeks 3–4: raise it to 20 minutes and add one 15-minute strength session at home.
3. Weeks 5–8: two strength sessions and 30 minutes walking, five days.
4. From then on: maintain. You are already at the full recommendation.

Notice the first week is ridiculously easy. That is deliberate. The reason people quit is not that the plan is too soft: it is that they start too hard, burn out and drop it in week three.

What to expect

With exercise alone, without changing your diet, the expected HbA1c fall is around half a point when aerobic and strength work are combined. It is less than weight loss achieves, but it is real, it has very few side effects if you build up gradually, and it improves ten other things along the way.

And there is something that does not show in any blood test: moving also helps you sleep. You notice a little on the day you train and, with consistency, sleep quality improves. Sleeping better in turn helps your glucose. It all goes together.