In this modern age, it is common to have what's lovingly termed a "desk job", which basically means sitting is usually maintained for many hours of the working day. Since COVID, more people are working from home, which means less commuting and all that it entails (walking to/from the car, walking around the office, etc.) and, that's right, more sitting. With this shift came more reports from patients saying they hurt when they are at their computer. Major highlights to consider in this predicament are work station set-up (check out this virtual workshop I did to help you make it just right) and physical activity or positions performed throughout the day. But then I started to wonder...what does the research say about sitting? You know I love to tell you what I found.
There have been multiple studies observing the musculoskeletal changes due to sitting. One study found that people that sat less than 4 hours per day and exercised at least 150 minutes per week had ~6 degrees more hip extension (how much the leg moves behind you) than participants who exercised less than 150 minutes per week and sat more than 7 hours per day. Hip extension range of motion comes in handy with running, walking, standing, and lying on your back. Often when we lack hip extension range of motion, we tap into a neighboring area to get more of it. These can be people who hyperextend their knees or their lower back. Another study found that there was a decrease in thoracic spine (ribcage level) mobility in those that sat for more than 7 hours per day and exercised less than 150 minutes per week. Why would we care about thoracic spine mobility? Thoracic spine mobility relates to MANY structures including neck mobility, shoulder mobility, breathing capacity, and SI joint stability, to name a few. Another study concluded that sedentary behavior, including prolonged sitting and prolonged driving time, was correlated with a moderate increase in the risk for low back pain. Some muscles have been shown to become fatigued with prolonged sitting, which sounds a lot like an overuse injury. One study observed the muscle activity in the trapezius and latissimus dorsi (back muscles) using EKG and found that they started to fatigue after 40 minutes of sitting. The intervention that best decreased this muscle fatigue was standing and stretching for 5 minutes. After stretching, the muscles could maintain their baseline of activity for 35-40 minutes until fatigue began again.
Prolonged sitting also affects our cardiovascular system. One studied observed that longer sitting time was correlated with severity of coronary atherosclerosis (plaque build-up in the walls of the vessels around the heart). Another paper looked at prolonged sitting combined with only taking 5,000 steps maximum per day and the correlation with peripheral artery disease, specifically endothelial dysfunction in the legs. That means that the lining of the blood vessels in the legs are more vulnerable to cardiovascular disease because they are getting decreased blood flow and decreased blood turbulence, which are two very important things! The good news is, these researchers have also observed that walking after or cycling for 45 minutes before prolonged sitting of 3 hours helped mitigate these effects.
As already suggested in many of these studies, the remedy to prolonged sitting is physical activity. Let's be honest, physical activity is the remedy to almost anything and everything! Many of these studies used 150 minutes of physical activity per week as the threshold of what is considered "active". Do you exercise at least that much? Some studies observed exercising before or after prolonged sitting while others intervened with "exercise snacks" scattered throughout the working day. There is no hard evidence as to how often someone should take breaks from sitting but my vote is every 45 minutes to an hour, if not more! Some great tricks to making yourself move often are having a water bottle at your desk so that you're constantly getting up to pee or getting up to refill your vessel, setting a timer on your phone, making a policy to stand during meetings, taking your laptop around to different areas of your house to make you stand, sit, squat, or kneel differently than the posture you were just in, making walking dates with friends in person or as a phone call, getting a dog to walk, creating a supportive exercise group at work where you share what you did that day, playing a fun song that motivates you to get up and move, or using an exercise app that has short movement activities. The goal here is to feel good in your mind and body. Don't focus on weight loss as the goal but don't be surprised if this is a side effect! Feel too tired to move this much? Guess what, we make our own energy in our cells called ATP as a result of...movement. So, get up!
Research articles used:
https://pubmed.ncbi.nlm.nih.gov/33188982/
https://pubmed.ncbi.nlm.nih.gov/32596017/