Making Sense of Sedentary Time

Published in

Amazon Halo Blog

5 min readFeb 18, 2021

I’m sure many of you have heard the saying “sitting is the new smoking.” But is it really true? Let’s dig a little deeper, starting with some definitions.

What is sedentary time and sedentary behavior?

Sedentary time is the amount of time a person spends engaging in sedentary behaviors during the course of a day (excluding sleep). And sedentary behavior is any behavior that requires very little fuel from your body (officially defined as an energy expenditure ≤1.5 metabolic equivalents, METs), while in a sitting, reclining or lying posture. Here are a few examples of sedentary behaviors: sitting while reading/writing/talking while sitting, sitting while watching TV, sitting or lying down while using smartphones/ tablets, and sitting while working. Did we mention sitting?

Here are some eye-opening stats*:

Sedentary jobs have increased more than 80% since the 1950’s, according to the American Heart Association.
Over 25% of American adults sit for more than 8 hours every day. 44% of those people get little to no exercise, according to a study by the CDC.
According to the WHO, 6% of Deaths Globally are linked to Physical Inactivity
People who sit for more than 7 hours per day or more are much more likely to develop depression, dementia and Alzheimer’s disease

* Of note, this does not reflect our behaviors during this global pandemic.

Why should we care about sedentary behaviors?

Medical evidence suggests that high levels of sedentary behavior (total sedentary time) negatively impact health independent of other factors including body weight, diet, and physical activity. For example, a 12-year study of 17,000 adults found that those who spent most of their time sitting were 50% more likely to have a shorter lifespan as compared to those that sit the least, even after controlling for confounding factors such as age, smoking, and amount of physical activity. When people sit and are not physically active, their muscles and bones can weaken, and they are more likely to gain weight because they burn fewer calories. Another paper found that even after adjusting for physical activity, sitting for long periods was associated with worse health outcomes including heart disease, Type 2 diabetes, and cancer. The takeaway is that physically activity does not completely offset the negative effects of a sedentary lifestyle centered around sitting.

What can we do about sedentary behavior?

Even if you exercise for 30 minutes a day, it matters what you do with the other 16.5 hours (assuming you sleep for 7 hours). Here are a few ways to reduce your sedentary time:

Increase your level of physical activity.
More recent research shows that high levels of exercise can lessen some of the risk. According to studies, 60–75 minutes of daily moderate activity (like steady walking) can counter the effects of too much sitting. Yet even for people with high levels of physical activity, there seems to be a threshold around 10–11 hours of sitting. Research shows that if you exceed 10 hours of sedentary time in a day (excluding sleep), your cardiovascular risk really goes up.

Break up your activity with sedentary behavior, not the other way around.
The evidence suggests the manner in which you accumulate sedentary time matters. “Prolongers” accumulate sedentary time in prolonged bouts (>20–30 minutes of continuous sedentary behavior) with few breaks. “Breakers” accumulate it in short sedentary bouts (<5–10 min of continuous sedentary behavior) with lots of breaks in between. Generally speaking, for the same amount of total sedentary in a day (excluding sleep),“breakers” are better off as compared to “prolongers.” We recognize that for most who work a desk job and for the many individuals who have been stuck at home during the pandemic, it may feel nearly impossible to get to such a low level of sedentary time, but it’s important to take frequent breaks and avoid prolonged bouts of sedentary behaviors when you can.

Keep moving.
Just standing up does not have a material impact on the health risks associated with sedentary behaviors — that’s why Halo counts standing still as sedentary time. In order to counteract the negative impact of prolonged sedentary bouts as well as total sedentary time, the latest scientific research suggests engaging in more physical activity — of any intensity level. According to a study by the University Of Utah School Of Medicine, just two minutes of physical activity for every hour of sitting can lower the risk of premature death by as much as 33%. You can spend this time stretching, walking, going for a bathroom break, or getting more water to prevent dehydration.

How does Halo measure sedentary time?

Halo measures sedentary time based on your movement and your heart rate (both of which are measured via sensors in the Halo Band). We use the heart rate signal to determine if you are actually “sedentary” or doing something else while sitting (for example, exercising on a stationary bike; you’re still sitting, but not sedentary). Halo tracks your movement and heart rate continuously and provides you insight into your sedentary time as it accumulates throughout the day. Halo incorporates sedentary time into the Activity Score to provide customers with a comprehensive view of their physical activity levels and its relation to heart health and longevity. Customers can see their sedentary time on the “Activity” page and can review their daily, weekly, and monthly trends to better understand patterns and behaviors associated with accumulation of sedentary time.

In summary, accumulating too much sedentary time over the course of the day can be harmful to your health. Being physically active does not completely offset the negative effects of a sedentary lifestyle centered around sitting. So, it’s really important that you focus on sitting less, taking frequent breaks, and doing something physically active during those breaks. Be well.

Maulik Majmudar is the Medical Officer for Amazon Halo. His current health and wellness goal is to reduce his sedentary time and sedentary bouts by going on walks and dancing with his kids (twin toddlers and a pre-schooler) every day.

Making Sense of Sedentary Time

What is sedentary time and sedentary behavior?

Why should we care about sedentary behaviors?

What can we do about sedentary behavior?

How does Halo measure sedentary time?

References:

Written by Maulik Majmudar, M.D.