Little has been known about what makes certain sitting reduction strategies effective, but it is known that the problems associated with prolonged sitting are independent of whether a person exercises regularly.
A new study reveals that increasing the levels of physical activity can be less effective at reducing prolonged sitting as compared to actually decreasing the sitting time.
A research team led by Dr. Benjamin Gardner from the Department of Psychology at the loPPN, Kings College London assessed 38 trials of interventions that were designed to reduce sitting time. They categorized the studies according to effectiveness and examined the strategies used in each trial to reduce sitting. The successful interventions typically educated the participants about the health benefits of reducing their sitting time.
Sixty percent of the assessments were found to be promising. Those who received the intervention did reduce their sitting time. The other 40 percent were found to be not promising meaning the interventions didnt reduce sitting time.
The successful interventions consisted of:
- Sit-stand desks at work
- Encouraging people to keep records of their own sitting time
- Setting individual goals for limiting sitting time
- Using prompts and cues to remind people to stop sitting
- Breaking up desk time with a short walk to offset the harm caused to vascular blood vessels
The researchers recommend that sitting time should be viewed as a separate behavior change than physical activity. These findings will be of interest to researchers and practitioners designing new ways to reduce prolonged sitting, because they suggest which strategies may be most fruitful, Gardner said. However, the findings should also be of interest to anyone looking to improve their health by reducing their own sitting time in their day-to-day lives, as many of these interventions can be adopted on an individual level.
The ill effects of high levels of sitting may prove to be especially damaging given that so many people sit for long periods, added study co-author Professor Stuart Biddle of Victoria University in Australia. The importance of this study is not in showing that interventions can work, but in pointing out how they might work. This is crucial if behavior is to be achieved more efficiently and effectively.
Vascular Impairment And Improvement
In a related study, researchers from the University of Missouri School of Medicine have discovered that when a person sits for six straight hours vascular function is impaired. They learned that walking for just 10 minutes after a prolonged period of sitting can restore vascular health.
The researchers compared the vascular function of 11 healthy young men before and after a period of prolonged sitting. They found that blood flow in a lower leg artery was greatly reduced after sitting at a desk for six hours. After a 10-minute self-paced walk, the participants could restore the impaired vascular function and improve blood flow.
Its easy for all of us to be consumed by work and lose track of time, subjecting ourselves to prolonged periods of inactivity, said Jaume Padilla, Ph.D., an assistant professor of nutrition and exercise physiology at the MU School of Medicine and lead author of the study. However, our study found that when you sit for six straight hours, or the majority of an eight-hour work day, blood flow to your legs is greatly reduced. We also found that just 10 minutes of walking after sitting for an extended time reversed the detrimental consequences. When you have decreased blood flow, the friction of the flowing blood on the artery wall, called shear stress, is also reduced. Moderate levels of shear stress are good for arterial health, whereas low levels of shear stress appear to be detrimental and reduce the ability of the artery to dilate.
Dilation is a sign of vascular health, Padilla continued. The more the artery can dilate and respond to stimuli, the healthier it is. Studies have shown that sitting less can lead to better metabolic and cardiovascular health. However, more research is needed to determine if repeated periods of reduced vascular function with prolonged sitting lead to long-term vascular complications.