Most of the advice about sitting is about not sitting. Stand up, walk more, get a standing desk, take a call while you’re on your feet... all good, all true, and all slightly beside the point on the days when life or work requires you to be seated at a desk for hours.
But there’s a way to offset a little of that, with a muscle that doesn’t need you to stand up at all. It’s called the soleus. It sits deep in your calf, under the more famous gastrocnemius, and it is the part of you that holds you upright and steady whenever you’re on your feet.
Marc Hamilton, a professor at the University of Houston who spent years making the case that sitting too much is a massive health problem, looked for a way to fix it without just asking people to stop sitting (because he knew they wouldn’t). He found that the soleus has an unusual talent: ‘activated’ the right way, it can keep its metabolism raised for hours, burning glucose and fat while you sit at your desk and do nothing else. He called the movement the soleus pushup.
It looks like almost nothing. You sit with your feet flat on the floor. You let your heels rise as high as they’ll go while your toes stay down, then let them drop, then repeat, in a slow, steady rhythm. If you’ve ever tapped your foot without thinking about it while concentrating, you already know the shape of it. The only difference is that this version is deliberate, and the muscle is doing the lifting rather than nervous energy.
Why it works comes down to how the soleus is built. It’s made almost entirely of slow, fatigue-resistant muscle fibre, the kind designed to keep going for hours without tiring, and it doesn’t rely on the body’s usual quick-burn glycogen stores. So instead of pulling energy from a limited tank and needing a rest, it can draw steadily on glucose and fat in the blood, for as long as you keep it gently going.
When participants performed the movement continuously for 3 hours after a glucose drink, their blood sugar response improved by about 52%, and they needed about 60% less insulin. Hamilton also found it roughly doubled the rate of fat metabolism between meals.
But worth knowing: those numbers came from people doing the movement more or less continuously in a lab, with sensors ensuring they were activating the muscle correctly. The effect lasts for hours because you keep it going for hours, not because a minute of heel-tapping buys you an afternoon off. Hamilton has said the movement is specific enough that, to get the maximum effect, you really want wearable feedback to confirm the right muscle was firing. So the sensible way to hold this is not as a hack or a quick fix, but as something to keep quietly ticking over while you’re already sitting, especially in the stretch after a meal when your blood sugar is rising and you’re going to be still anyway.
Which is what makes it a good microhabit. No schedule change, yoga mat, change of clothes, or gap in calendar needed! So this week, try it. Next time you sit down to work after eating, plant your feet, and set your heels tapping in that slow, even rhythm. Let the muscle do the work. Keep it going while you answer emails, while you’re on a call, while you read this.
The Mille Microhabit is a collection of small things, easy to incorporate, and with big impact. Nothing here is a substitute for advice from your own doctor, particularly if you’re managing blood sugar or diabetes.
1,000 Ways to Live Well is a Mille publication. Mille is a modern nutrition brand built around everyday rituals, starting with protein that doesn't ask you to compromise on taste. millesupergrain.com