Surprising News About Activity

We have learned many abbreviated, initial-defined terms for various conditions, and here are two more: MVPA and LPA which stand, respectively, for moderate-to-vigorous physical activity and light physical activity. These two are in the news because of a recent, rather surprising report.

But first, the startling background information:

Recent reports concluded that more than 80% of adolescents across the globe do not meet the World Health Organization’s recommended average of 60 minutes/day of MVPA. It is estimated that physical inactivity will have caused 500 million new cases of heart disease, obesity, diabetes or other noncommunicable diseases by 2030…

Part of the basic problem with studying this area is that BMI or body mass index “is a poor measure of obesity in childhood and adolescence since it does not distinguish between muscle mass and fat mass.” But it is relatively easy to obtain, and universally used in the absence of something better.

Here is a less-than-two-minute video explaining how a person’s body mass index figure is arrived at. The American Academy of Pediatrics has long recommended that children be measured by this standard when quite small, and whenever it is deemed necessary from then on. This is how they are determined to be obese, or at risk of obesity.

The universities of Bristol, Exeter, Colorado, and Eastern Finland all collaborated on a study of activity levels, whose results were published toward the end of last year. It is described as “the largest and the longest follow-up objectively measured PA (physical activity) and fat mass study in the world.”

For 13 years, it measured everything about its subjects, and we do mean everything:

Waist-worn accelerometer measures of sedentary time, LPA, and MVPA, and DEXA-measured fat mass and skeletal muscle mass were collected at ages 11, 15, and 24 years. These children also had their fasting blood samples repeatedly measured for, e.g., glucose, insulin, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglyceride, and high-sensitivity C-reactive protein. In addition, blood pressure, heart rate, smoking status, socio-economic status, and family history of cardiovascular disease were measured and controlled for in the analyses.

Overall, it was determined that moderate-to-vigorous physical activity “had minimal or no effect in reducing childhood BMI-obesity.” But guess what does have an astonishing effect? At least three hours per day of light physical activity, which includes walking, household chores, slow bicycling, swimming, and dancing. This much LPA “promotes healthy heart, lowers inflammation and lowers cholesterol levels among children, adolescents, and young adults better than MVPA.”

So, rather than recommending an hour a day of moderate-to-vigorous activity, all advice-giving entities — “public health experts, health policymakers, health journalists and bloggers, paediatricians, and parents” — should switch to specifying at least three daily hours of light physical activity.

In other words, kids don’t need to be out there thrashing around and getting sweaty. They just need to be moving consistently, like they used to do when walking to and from school, weeding kitchen gardens, rounding up animals from the fields, and biking around the neighborhood tossing rolled-up newspapers onto porches.

As it turns out, and as many grouchy elders have maintained all along, indulging children with soft privileged lives of leisure and passive entertainment does not, in the long run, do them any favors.

Your responses and feedback are welcome!

Source: “Light physical activity shows great promise in reversing childhood obesity caused by being sedentary,”, 12/18/23
Source: “Calculate BMI — The Body Mass Index Formula,”, undated
Image by Dave Schappell/CC BY-SA 2.0 DEED

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About Dr. Robert A. Pretlow

Dr. Robert A. Pretlow is a pediatrician and childhood obesity specialist. He has been researching and spreading awareness on the childhood obesity epidemic in the US for more than a decade.
You can contact Dr. Pretlow at:


Dr. Pretlow’s invited presentation at the American Society of Animal Science 2020 Conference
What’s Causing Obesity in Companion Animals and What Can We Do About It

Dr. Pretlow’s invited presentation at the World Obesity Federation 2019 Conference:
Food/Eating Addiction and the Displacement Mechanism

Dr. Pretlow’s Multi-Center Clinical Trial Kick-off Speech 2018:
Obesity: Tackling the Root Cause

Dr. Pretlow’s 2017 Workshop on
Treatment of Obesity Using the Addiction Model

Dr. Pretlow’s invited presentation for
TEC and UNC 2016

Dr. Pretlow’s invited presentation at the 2015 Obesity Summit in London, UK.

Dr. Pretlow’s invited keynote at the 2014 European Childhood Obesity Group Congress in Salzburg, Austria.

Dr. Pretlow’s presentation at the 2013 European Congress on Obesity in Liverpool, UK.

Dr. Pretlow’s presentation at the 2011 International Conference on Childhood Obesity in Lisbon, Portugal.

Dr. Pretlow’s presentation at the 2010 Uniting Against Childhood Obesity Conference in Houston, TX.

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