Carrie Schmitz, Senior Manager of Human Factors & Ergonomics Research, at Ergotron
Most of us have heard warnings about how sitting is the new smoking, and how breaking up sitting time throughout the working day has many health benefits.
I support this active workstyle based on my own experience using a sit-stand desk for the last 10 years and because of evidence-based, scientific data. But I’ve always wondered: if interrupting sitting with low-level movement throughout the day is the remedy for sedentary time, wouldn’t it be enough for us to wave our arms around periodically? Why do we have to get out of our chairs every 30 minutes and stand?
At the National Ergonomics Conference and ErgoExpo last August, I had a chance to discuss this topic with Joan Vernikos, author of “Sitting Kills, Moving Heals: How Everyday Movement Will Prevent Pain, Illness, and Early Death – and Exercise Alone Won’t.” I asked Dr. Vernikos if there was a unique health impact related to moving the lower part of the body that couldn’t be accomplished by moving the upper half of the body alone. Her answer? A resounding, “yes!”
Since that conversation, I have discovered similar insights that highlight the importance of lower body movement. In a study of London transportation workers, researchers documented a higher risk of cardiovascular disease among bus drivers who sat behind the wheel versus those conductors who stood, walked the aisles, and climbed stairs while punching tickets. What was the difference between the driver and a conductor’s behaviour? One sat with the legs from hip to knee parallel to the floor while the corresponding limbs of the conductor were vertical and often in motion.
The postural muscles of our legs, buttocks and lower back have special qualities that smaller muscle groups, like our arms, do not. These “slow twitch” muscles are designed for endurance. They are packed with mitochondria for energy conversion and myoglobin to carry oxygen to muscle fibres for quick bursts of movement.
At a molecular level, postural muscles send powerful signals about the need to produce more energy, creating a crucial relationship between low intensity physical activity and our metabolism, endocrine system, and even mood and mental functions. If these muscles are not regularly engaged, numerous systems begin to slow down with catastrophic long-term consequences starting as early as age 20. Obesity, Type 2 diabetes, fatty liver, hardened arteries and high blood pressure are just a few markers related to reduced movement in the lower body.
If slow-twitch muscles are not activated over time, they lose the high ratio of mitochondria myoglobin that differentiate them from fast-twitch muscles until they become fast-twitch muscles. You can see the difference in the visualisation below:
Most daily activities use slow twitch muscles. Dr. James Levine describes these activities as NEAT (non-exercise activity thermogenesis). We now know that exercise alone is not enough to keep us healthy. Non-exercise, NEAT activity is just as important. Most of your day should be spent doing low-intensity, non-exercise physical activity, in addition to at least 150 minutes of moderate to vigorous physical activity. Unfortunately, in our highly digital, mechanized world, NEAT has largely been replaced with time and labour saving devices like lawn mowers, washing machines, cars and fast food. Even our leisure time movement has been undercut: watching a ball game, online shopping, movies and TV are all spent sitting.
We are bombarded daily with messages about our health. From fitness apps to food choices, we are directed to a myriad of ways to claim the one thing that seems to grow more elusive every day. Finding time to eat right, exercise and do all that is needed to become and stay healthy sometimes feels like a full-time job itself. No wonder we seek ways to save time, but at what cost?
Through their investigations, Dr. Vernikos, Dr. Hamilton, Dr. Levine and the others like them are revealing ways we can all start working toward our health in a smarter way. Keep up your exercise routine, but don’t underestimate the need for plenty of low-level activity. Use the muscle groups in your lower part of your body to your advantage. Stand more often. Use tools, like a sit-stand desk, to activate the sedentary parts of your day.
We still have much to learn, but what we do know is that movement matters, and not just dedicated time at the gym. Consider how much time you spend sitting and how small changes you might make could add up to a healthier working life!
Carrie has specialised in computer ergonomics and office wellness for nearly 20 of her 30-year career in market research. At Ergotron, Carrie oversees ergonomics research and outreach, working closely with top researchers in the field to advance knowledge around the impacts sit-stand activity has on our health and wellbeing. Carrie is deeply committed to educating the public on the importance of healthy work/life balance, and her work with prominent universities and healthcare organisations has been important to the establishment of evidence-based data around the benefits of sit-stand workstations.