The World Health Organisation (WHO) recommends exercising at least two-and-a-half hours per week, and preferably 30 minutes every day. Movement is crucial to our circulation – blood and lymph circulation and metabolism needs muscle movement to be able to fulfill the needs of our bodies. Prolonged sitting has several negative effects on our health: chronic back and neck pain, increased risk of cancer in the pelvic area when sitting more than seven hours per day, increased risk of death when sitting more than eight hours per day, etc (Tremblay et al, 2010 and van der Ploeg et al, 2012). Modern sedentary behaviour has severe negative impacts on vascular and metabolic health, which in turn causes sitting disorders (SD). Studies also show that sitting has negative impacts on health, even though one might be physically active in one’s leisure time. We should be active also during working hours and not just decrease the hours spent sitting.
Dangers of sitting to metabolism
Prolonged sitting disturbs metabolic functions and causes plasma triglyceride levels to rise and high-density lipoprotein (HDL) cholesterol levels to decrease. Sedentary behaviour can also affect metabolism through changes in muscle glucose transporter protein content (van der Ploeg et al, 2012). This means that when muscles are tense and inactive while sitting, metabolism and muscle effectiveness decreases. Studies show that prolonged sitting is a hazard for metabolic health (Hamburg et al, 2007).
A lymphatic system, with 1 –15 litres of lymph liquid, is constantly cleaning our tissues. The smallest pressure from furniture, clothes or muscle tensions disturbs it.
Damaging positions and circulation in dental care
Reduced metabolic health in conventional sitting comes partly from the pressure caused by the furniture on thighs, buttocks, genitals and the pelvic floor area. Traditional sitting position prevents movement. Sitting becomes inactive and static. This inactivity, together with long sitting hours, is truly hazardous for our health.
Also, in dental care, people usually work in bad positions: the posture is poor, there’s constant pressure from the furniture and muscles are inactive and tense. The decreased circulation (lymph and blood) causes many health risks all over the body:
- Poor circulation into the head, headaches, tired eyes, slow thinking
- Poor circulation in the shoulder and neck area, tensions, aches
- Poor circulation in the breast and chest area, increased health risks
- Degeneration in spine and all its tissues, pains, discomfort
- Increased health risks in the pelvic, genital and inner pelvic area
- Varicose veins, building up of cellulite
- Degeneration in knee and hip joints, arthritis.
Why and how to improve circulation
To avoid the risks from sitting we should sit less and preferably have a few minutes conscious health movements at least once an hour. Proper physical exercise during the leisure time strengthens the circulation capacity. Activity during the day uses this capacity to refresh and clean up the tissues. Just cutting down the sitting hours is not enough; we ought to increase activity in our workday and leisure time (van der Ploeg et al, 2012).
Ergonomics and human physiology provides us with a practical solution. It was known already in the 1950s that an upright, riding-like sitting posture, where there is a 135° angle in the hip, is the best way to maintain the natural and healthy curve in the lower back (Keegan, 1953). If we change our physical environment by having seats that encourage us to move, we can activate our body even during sitting. As a result, we improve our physical and mental health. Every move we make when sitting like this will activate the muscles, circulation and metabolism.
In addition to muscle activity and increased circulation, active sitting has other benefits as well. Physiotherapist Marie Jalkanen recommends that, dental professionals especially, should pay more attention to their breathing: ‘When sitting all day long in a tense and static position, breathing becomes very shallow. But when you sit straight, for example on a divided saddle chair, and activate your stomach muscles during the day, your breathing deepens. In this sitting posture, your circulation is better, not only in your muscles, but also in your brain. Increased circulation together with deeper breathing will increase your work effectiveness.’
Divided saddle chairs provide a good posture without pressure on the muscles or on the genital area, because the weight is on the sitting bones and the seat has a gap in the middle. ‘When sitting on a traditional chair or on a one-part saddle chair, the pressure on the genital area becomes uncomfortable. Then you unconsciously tilt your hip backwards to avoid it. You begin to slouch and get problems sooner or later,’ says Marie Jalkanen. ‘But a divided saddle chair can prevent back problems, erectile dysfunctions and prostate problems.’
Reijo Koskelo, PhD in East Finland University, EFU, has undertaken research on sitting pressures on different kinds of chairs. Figure 4 show clearly that the most pressure (red) is on the buttocks and genital area when sitting on a traditional chair.
Figure 4: The most pressure (red) is on the buttocks and genital area when sitting on a traditional chair
Figure 5 shows the pressure on an undivided saddle chair. The least pressure comes from a divided saddle chair.
Figure 5: Pressure on an undivided saddle chair
In Figure 6 one can see that most of the pressure is on the sitting bones. Circulation and metabolism can function freely.
Figure 6: Pressure is on the sitting bones with an undivided saddle chair
Active and relatively healthy sitting is easy with, for instance, a Salli Swingfit saddle chair. One can get small movement in the back, which builds up the core muscles strength and increases the circulation and metabolism. When rolling and reaching with a saddle chair, one also moves the legs, which prevents varicose veins. ‘Because you are in balance, no backrest is needed. Leaning on a backrest just decreases the circulation. If the adjustments of the unit allow, it’s good to work standing every now and again,’ Marie Jalkanen says.
Sitting can shorten your life or even indirectly kill you. Activate the body; that’s the first step. We can sit actively (sit on a divided saddle chair and get up for a while to exercise) and we can try to be more active in our daily tasks (walk-and-talk on the phone, have walking meetings, clean the garden without machinery, choose the stairs, walk to places, etc). This will boost the circulation and keep us healthy and fresh during the day.
To find out more information please visit www.salli.com, email [email protected] or call +358 10 2701 210.
Hamburg, N., McMackin, C., Huang, A., Shenouda, S., Widlansky, M., Schulz, E., Gokce, N., Ruderman, N., Keaney, J. and Vita, J. (2007) ’Physical inactivity rapidly induces insulin resistance and microvascular dysfunction in healthy volunteers.’ Arterioscler Thromb Vasc Biol. 27(12): 2650–2656.
Keegan, J. (1953) ‘Alterations of the lumbar curve related to posture and seating.’ Journal of Bone and Joint Surgery. 35(3): 589–603.
Tremblay, M., Colley, R., Saunders, T., Healy, G. and Owen, N. (2010) ‘Physiological and health implications of a sedentary lifestyle.’ Appl Physiol Nutr Metab. 35(6): 725-740.
van der Ploeg, H., Chey, T., Korda, R., Banks, E. and Bauman, A. (2012) ‘Sitting Time and All-Cause Mortality Riskin 222 497 Australian Adults.’ Arch Intern Med 172 (6): 494-500.