Category: In The News
Today’s post comes from Dr. Olaf Verschuren, of the Centre of Excellence for Rehabilitation Medicine in Utrecht.
Children with cerebral palsy and adults with stroke are advised to participate in moderate to vigorous physical activity (MVPA), such as brisk walking and running. However, these patient groups develop or return to an inactive lifestyle due to the different physical, cognitive and environmental barriers, and often become deconditioned and predisposed to a sedentary lifestyle that may contribute to an increased risk for their health.
As we all know, prolonged periods of sedentary behavior are associated with several metabolic risk factors and all-cause mortality, independent of participation in physical activity. Therefore, people with stroke and children with cerebral palsy should not only participate in physical activity but also try to reduce or break up sedentary time as this might reduce the high risk of health problems. However, there is a lack of knowledge about sedentary behavior in these patient groups.
The SBRN defined ‘‘sedentary’’ as any waking behaviour characterized by an energy expenditure ≤1.5 metabolic equivalent of task (MET) while in a sitting or reclining posture. Despite sitting being an omnipresent behavior in all people, there are no studies actually assessing the energy expenditure of sitting and standing in people with stroke and children with cerebral palsy. So, in order to be able to support people with stroke and children with cerebral palsy to engage in activities that generate light to moderate intensity energy expenditure (that exceeds the 1.5 METs) and confer some health benefit, it is necessary to know which activities generate the required physiological response. Thus, when operationalizing sedentary behavior against low intensity physical activities such as sitting, standing and walking, we have to rely on the energy expenditure.
Olaf Verschuren (researcher at the Brain Center Rudolf Magnus and Center of Excellence for Rehabilitation Medicine, University Medical Center Utrecht and De Hoogstraat Rehabilitation, in Utrecht, The Netherlands) and colleagues recently published two studies that objectively measured and calculated the energy expended by people with stroke and children with cerebral palsy during near sedentary behaviors.
The main findings:
- Children and adolescents with cerebral palsy across all functional had energy expenditures higher than 1.5 METs during standing. Our findings related to energy expenditure therefore suggest that changing children’s position to a standing position may contribute to the accumulation of light activity and reduce sedentary behavior. See Figure 1.
- The findings of the study in people with stroke demonstrate that the energy expenditure during typical sedentary behaviors (sitting supported and unsupported is very narrowly bounded around 1.0 METs. Energy expenditure during sitting and standing was ≤1.5 METs for almost all functional levels. Independent wheelchair propulsion and walking seem to be light activities (≥1.5 METs) that could be used by people with stroke to interrupt sedentary behavior. See Figure 2.
Verschuren, Olaf, et al. “Muscle activation and energy-requirements for varying postures in children and adolescents with cerebral palsy.” The Journal of pediatrics 165.5 (2014): 1011-1016.
Verschuren, Olaf, et al. “Characterizing energy expenditure during sedentary behavior after stroke.” Archives of Physical Medicine and Rehabilitation (2015).
For the first time, this new study has shown that increasing levels of physical activity is likely to be much less effective at reducing prolonged sitting than directly attempting to decrease sitting time.
The research team, led by Dr Benjamin Gardner, from the Department of Psychology at the IoPPN, King’s College London, searched the current existing literature on trials of interventions that sought to reduce sitting time. The team then categorised these studies according to their effectiveness, and examined the strategies that had been used in each trial to try to reduce sitting. The studies were deemed promising, where those who received the intervention did reduce sitting time, or not promising, where the interventions did not reduce sitting time.
Out of the 38 interventions assessed, a majority of 23 (60 per cent) were found promising whilst 15 (39 per cent) were found not promising.
Some of the promising interventions included the provision of sit-stand desks at work, though other techniques such as encouraging people to keep records of their own sitting time, setting individual goals for limiting sitting time, and using prompts and cues to remind people to stop them sitting, were also found to help reduce sitting time, even when used in isolation.
In addition, effective interventions tended to educate people about the health benefits of reducing their sitting time.
The full article is available via the Stone Hearth Newsletters.
A new paper in IJBNPA examines the prospective associations between physical activity, sedentary behaviour, and academic achievement in British teens:
We investigated prospective associations between physical activity/sedentary behaviour (PA/SED) and General Certificate of Secondary Education (GCSE) results in British adolescents.
Exposures were objective PA/SED and self-reported sedentary behaviours (screen (TV, Internet, Computer Games)/non-screen (homework, reading)) measured in 845 adolescents (14·5y ± 0·5y; 43·6 % male). GCSE results at 16y were obtained from national records. Associations between exposures and academic performance (total exam points) were assessed using multilevel mixed-effects linear regression adjusted for mood, BMI z-score, deprivation, sex, season and school; potential interactions were investigated.
PA was not associated with academic performance. One-hour more accelerometer-assessed SED was associated with (β(95 % CI)) 6·9(1·5,12·4) more GCSE points. An extra hour of screen time was associated with 9.3(−14·3,-4·3) fewer points whereas an extra hour of non-screen time (reading/homework) was associated with 23·1(14·6,31·6) more points. Screen time was still associated with poorer scores after adjusting for objective PA/SED and reading/homework.
An extra hour/day of screen time at 14·5y is approximately equivalent to two fewer GCSE grades (e.g., from B to D) at 16y. Strategies to achieve the right balance between screen and non-screen time may be important for improving academic performance. Concerns that encouraging more physical activity may result in decreased academic performance seem unfounded.
The full text can be access for free via the IJBNPA website.
Fast Company Design has an article on a recent systematic review summarizing the available evidence on active workstations:
If it wasn’t already clear through common sense, it’s become painfully clear through science that sitting all day is terrible for your health. What’s especially alarming about this evidence is that extra physical activity doesn’t seem to offset the costs of what researchers call“prolonged sedentary time.” Just as jogging and tomato juice don’t make up for a night of smoking and drinking, a little evening exercisedoesn’t erase the physical damage done by a full work day at your desk.
In response some people have turned to active desks—be it a standing workspace or even a treadmill desk—but the research on this recent trend has been too scattered to draw clear conclusions on its benefits (and potential drawbacks). At least until now. A trio of Canada-based researchers has analyzed the strongest 23 active desk studies to draw some conclusions on how standing and treadmill desks impact both physiological health and psychological performance.
The full article is available via the Fast Company Design website.
A new study in the International Journal of Environmental Research and Public Health examines the influence of urban design, neighbourhood built and social environment, and household and individual factors on the interdependent relationship between objectively measured physical activity and sedentary behaviour in children. The abstract:
Even though physical activity and sedentary behaviour are two distinct behaviours, their interdependent relationship needs to be studied in the same environment. This study examines the influence of urban design, neighbourhood built and social environment, and household and individual factors on the interdependent relationship between objectively measured physical activity and sedentary behaviour in children in the Canadian city of Saskatoon. Saskatoon’s built environment was assessed by two validated observation tools. Neighbourhood socioeconomic variables were derived from 2006 Statistics Canada Census and 2010 G5 Census projections. A questionnaire was administered to 10–14 year old children to collect individual and household data, followed by accelerometry to collect physical activity and sedentary behaviour data. Multilevel logistic regression models were developed to understand the interrelationship between physical activity and sedentary behaviour in the context of diverse environmental exposures. A complex set of factors including denser built environment, positive peer relationships and consistent parental support influenced the interrelationship between physical activity and sedentary behaviour. In developing interventions to facilitate active living, it is not only imperative to delineate pathways through which diverse environmental exposures influence physical activity and sedentary behaviour, but also to account for the interrelationship between physical activity and sedentary behaviour.
The full paper is available for free via the International Journal of Environmental Research and Public Health website.
A new study in the European Heart Journal has investigated the impact of (statistically) replacing sitting with standing or walking. The abstract:
Aims While excessive sitting time is related adversely to cardio-metabolic health, it is unknown whether standing is a suitable replacement activity or whether ambulatory movement is required. Using isotemporal substitution analyses, we modelled cross-sectional associations with cardio-metabolic risk biomarkers of reallocating time (2 h/day) from sitting to standing or to stepping.
Methods and results A subsample of participants from the 2011/12 Australian Diabetes, Obesity, and Lifestyle Study wore the posture-based activPAL3 monitor [36–80 years (mean 57.9, SD 9.9 years); 57% women; n = 698 with data]. Associations of activPAL3-derived mean daily time sitting/lying (sitting), standing and stepping with body mass index (BMI), waist circumference, blood pressure, HbA1c, fasting glucose and lipids (high-density lipoprotein-, HDL, and low-density lipoprotein-cholesterol, total/HDL-cholesterol ratio, and triglycerides), and 2-h plasma glucose were examined. Adjusted for relevant confounders, sitting-to-standing reallocations were only significantly (P < 0.05) associated with approximately 2% lower fasting plasma glucose, 11% lower triglycerides, 6% lower total/HDL-cholesterol ratio, and 0.06 mmol/L higher HDL-cholesterol per 2 h/day. Sitting-to-stepping reallocations were only significantly associated with approximately 11% lower BMI, 7.5 cm lower waist circumference, 11% lower 2-h plasma glucose, 14% lower triglycerides, and 0.10 mmol/L higher HDL-cholesterol per 2 h/ day, while standing-to-stepping reallocations were only significantly associated with ∼10% lower BMI, 7 cm lower waist circumference, and 11% lower 2-h plasma glucose.
Conclusion Findings suggested that sitting-reduction strategies targeting increased standing, stepping, or both, may benefit cardio-metabolic health. Standing is a simple alternative to sitting, and requires further examination in prospective and intervention studies.
The full paper is available for free via the European Heart Journal website.
A systematic review exploring the link between sedentary behaviour and anxiety was published recently in the journal BMC Public Health.
Previous research has linked sedentary behaviour (SB) to adverse physical health outcomes in adults and youth. Although evidence for the relationship between SB and mental health outcomes (e.g., depression) is emerging, little is known regarding risk of anxiety.
A systematic search for original research investigating the association between SB and risk of anxiety was performed using numerous electronic databases. A total of nine observational studies (seven cross-sectional and two longitudinal) were identified. Methodological quality of studies was assessed and a best-evidence synthesis was conducted.
One cross-sectional study demonstrated a strong methodological quality, five cross-sectional studies demonstrated a moderate methodological quality and three studies (two cross-sectional one longitudinal) received a weak methodological quality rating. Overall, there was moderate evidence for a positive relationship between total SB and anxiety risk as well as for a positive relationship between sitting time and anxiety risk. There was inconsistent evidence for the relationship between screen time, television viewing time, computer use, and anxiety risk.
Limited evidence is available on the association between SB and risk of anxiety. However, our findings suggest a positive association (i.e. anxiety risk increases as SB time increases) may exist (particularly between sitting time and risk of anxiety). Further high-quality longitudinal/interventional research is needed to confirm findings and determine the direction of these relationships.
The full review is available for free via the BMC Public Health website.
Last week an Expert Statement commissioned by Active Working CIC and Public Health England was published in the British Journal of Sports Medicine titled “The Sedentary Office: a growing case for change towards better health and productivity” (available here).
From the Get Britain Standing website:
Based on the current evidence Active Working recommends:
- 2 hours daily of standing and light activity (light walking) during working hours, eventually progressing to a total of 4 hours for all office workers whose jobs are predominantly desk based
- Regularly breaking up seated based work with standing based work, with the use of adjustable sit-stand desks/work stations
- Avoidance of prolonged static standing, which may be as harmful as prolonged sitting
- Altering posture/light walking to alleviate possible musculoskeletal pain and fatigue as part of the adaptive process
- As well as encouraging staff to embrace other healthy behaviours, such as cutting down on drinking and smoking, eating a nutritious diet, and alleviating stress, employers should also warn their staff about the potential dangers of too much time spent sitting down either at work or at home
The full Expert Statement is available here.
This is one of the questions that will be addressed at the upcoming, Loch Lomond Lectures – Context is Key: Unlocking Physical Behaviour Data.
This event is a small, informal and participative retreat style meeting hosted by Malcolm Granat, Professor of Health and Rehabilitation Sciences, School of Health Science, University of Salford, and featuring several renowned international speakers.
When: 7 & 8 June 2015
Location: Loch Lomond, Scotland
March 23-29 is Unplug and Play Week in Canada. From ParticipACTION:
Turn off the screens. Turn up the play.
Now that our electronics are only ever a finger’s reach away, the average Canadian child spends close to 8hrs a day in front of a screen. So let’s help our children by leading by example. Let’s put our electronics down for at least 60 minutes a day and get outside for some physical activity. To help, here’s an Unplug & Play Checklist with a week’s worth of ideas. You’ll also find a customizable certificate to award your little ones if they stay active for all 7 days.
The site also offers a screen time log to track screen time. Happy Unplug and Play Week!