Longevity Briefs: You Should Probably Stand Up Now

Longevity briefs provides a short summary of novel research in biology, medicine, or biotechnology that caught the attention of our researchers in Oxford, due to its potential to improve our health, wellbeing, and longevity.

The problem:

As we’ve discussed in the past, some evidence suggests that prolonged periods spent sitting are uniquely bad for your health irrespective of your level of physical activity. That is to say that if two people do the same amount of physical exercise during the day, but one of them spends more time sitting down, they will be worse off health-wise. Several mechanisms have been proposed to explain this. One of these is that sitting for longer periods impairs the ability of muscles to absorb glucose (sugar) from the blood, reducing the body’s ability to regulate blood sugar. In this study, researchers conduct an interesting experiment to investigate how the downsides of sitting might best be mitigated.

The discovery:

Researchers discovered that interrupting long periods of sitting with frequent, short bouts of physical activity was significantly better for blood sugar levels than a single long bout of physical exercise, at least in people who were overweight or obese. To show this, researchers took 18 overweight or obese participants and split them into four groups. Each group sat for 8 hours, but three of the groups were assigned exercise. One group engaged in a single, 30 minute walk on a treadmill about an hour into the sitting period. The other two groups had their sitting interrupted 10 times over the course of the experiment with shorter bouts of either walking or squatting. The experiment was well controlled so that each intervention group had the same calorie expenditure, ate the same diet, and even had the same toilet breaks. Groups were rotated so that each participant did each experiment once, with a 7-day ‘washout’ in between each one. 

The group that performed a single bout of walking unsurprisingly had significantly better blood sugar control than the sedentary group. However, both groups that engaged in 10 bouts of activity, whether walking or squatting, had significantly improved blood sugar control compared to the group that only exercised once, even though all groups consumed the same number of calories.

The implications:

The study suggests that if you are going to be sitting down for an extended period of time, it’s better to interrupt the sitting with more frequent, shorter bouts of activity. But the question remains: why? The researchers have a proposition. In addition to measuring blood sugar, they also used electrodes to measure the activation of certain muscle groups. They found that activation of the quads and glutes, but not other muscles, was significantly associated with blood sugar reductions. In other words, the activation of muscles involved in the process of standing up might be as important, if not more so, than the exercise that follows.