Newsletter #307

A hallmark of modernity is pervasive incentivization to sit. Most of us involved with knowledge-based work need to sit in order to make a living (standing/treadmill desks notwithstanding). And contemporary entertainment options tend to be fairly sedentary as well.

In short, we spend more time sitting than perhaps ever before.

This is not ideal, because a veritable mountain of evidence suggests that prolonged sitting leads to poorer glycemic control — even in non-diabetics and in people who are a healthy body weight. And how well your body controls blood sugar is paramount for both lifespan and healthspan. For example, centenarians have lower blood sugar levels, and their bloodwork exhibits this difference decades before they hit their 100th birthday. Furthermore, elevated blood glucose, even within the normal range, is associated with accelerated brain aging.

The obvious solution, of course, is introducing more movement. Exercise lowers blood glucose by stimulating receptors that help shuttle sugar out of the blood and into your hungry muscles. The problem is that the physiological toll of sedentary behavior appears to be at least partially independent of moderate-to-vigorous physical activity. In other words, going for a workout every morning may not cancel out the eight hours that you spent sitting in front of your computer subsequently.

One potential solution is to spread out more activity throughout the day. Martin Gibala at McMaster University has focused a lot of his research on "exercise snacks." The idea here is distributing short bursts of activity within long periods of sitting, to disrupt the deleterious effects of immobility. As the word "snack" implies, these are very brief bouts of movement, less than a minute long, so it's a very practical intervention.

Importantly, this sort of protocol may provide other health benefits. As we have discussed previously in this newsletter, exercise snacks  can combat vascular dysfunction by restoring healthy blood flow to the legs, and they have even been shown to enhance the ability of muscles to utilize amino acids for muscle protein synthesis.

Researchers at the University of British Columbia recruited 12 healthy young men and 11 adults with overweight/obesity, and had them visit the lab on two occasions to go through two different experimental trials.

In one session, participants sat in a chair for 9 hours, and were asked to move as little as possible.

In the other session, participants also sat in a chair for 9 hours. However, this time, they got up once per hour and ascended three flights of stairs at a vigorous pace (total of 15-30 sec stair climbing).

During both trials, subjects were provided identical standardized meals, and blood samples were taken every half hour to gauge the physiological effects of the intervention.

During the stair climbing intervention, overweight/obese participants saw a 16.5% decrease in total insulin levels across the day (AUC). This makes sense. Exercise boosts insulin sensitivity, meaning that the body doesn’t need to churn out quite as much of the hormone in order to maintain homeostasis. This effect wasn’t seen in the healthy young men, presumably because they were already very insulin sensitive.

Notably, the overweight subjects also saw a significant (–21%) reduction in total free fatty acids. Elevated plasma levels of free fatty acids are very commonly seen in obesity, and they are thought to be a key driver of insulin resistance. Reduced exposure to these lipids would be expected to enhance insulin sensitivity, and attenuate the increased risk of type 2 diabetes that usually accompanies overweight and obesity.

What I like most about this intervention is how practical it is. Virtually anyone can take a break for less than a minute every hour to move around, and it certainly doesn’t have to be stair climbing — other similar trials have used walking briskly on a treadmill, getting on an exercise bike, or performing basic bodyweight exercises.

Dogs have exquisitely sensitive noses. They have about 50 times as many scent receptors as humans do, and as a result their sense of smell is thousands of times sharper than ours. As a result, they can pick up on a lot of things that wholly elude us.

For instance, when blood sugar goes way up or way down, levels of certain chemicals in our breath rise dramatically. Humans cannot detect these changes, but a dog can easily smell the difference.

Diabetes alert dogs, which have been trained to alert their owners of impending hypoglycemia, have been in service since 2009. Unfortunately, they are expensive to train and in short supply, so hopefully technological solutions are on the horizon.

I stumbled upon these electrolyte packets at the grocery stores and was pleasantly surprised by the contents. Good balance of potassium and sodium (700mg and 500mg respectively), reasonably tasty, and very easy to use during long workout sessions.

This week, we’d like to highlight our how-to guide for chrononutrition.

When we talk about diet, we often fixate on what we are eating. But we are gradually realizing that when we eat also has a significant impact on our health and our daily performance. This guide will help show you how to optimize your food timing, in alignment with the latest scientific research.

Wishing you the best,

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