Do Young Kids Pose a Barrier to Physically Activity?
Continuing the theme of mediators and barriers to physical activity, I’d like to draw my readers attention to an interesting paper by Kristi Adamo and colleagues from the University of Ottawa, just published in the American Journal of Preventive Medicine. Adamo and colleagues examined the association of having dependent children of different ages in the home on two measures of parental physical activity: daily moderate-to-vigorous physical activity (MVPA) and likelihood of meeting the guideline of 150 minutes of MVPA per week accumulated in 10-minute bouts. They analysed data from the 2007-2009 Canadian Health Measures Survey (n=2315), in which MVPA was measured directly using accelerometry. All models were adjusted for parental age, marital status, household income, employment, and BMI. It turns out (not surprisingly perhaps) that mothers whose youngest child was younger than 6 years and fathers whose youngest was aged 6-11 years engaged in fewer minutes of daily MVPA than those without dependent children (by about 50 mins less per week, respectively). Both moms and dads were about 70% less likely to meet the minimum levels of MVPA recommended in guidelines (150 minutes per week, in bouts of ≥10 minutes), if their youngest child in the home was aged <6 years. Thus, parents of young children are missing out on approximately one third of their weekly MVPA needs. It appears therefore that having young kids at home may pose a significant barrier to accumulating enough MVPA for parents. As the authors conclude, “Given the many physiologic, psychological, and social benefits of healthy active living, research efforts should continue to focus on strategies to encourage parents with young children to establish or re-engage in a physically active lifestyle, not only for their own health but to model healthy behavior for the next generation.” I’d certainly love to hear from my readers about how having young kids has impacted their physical activity levels or how they have perhaps been able to avoid this impact. AMS Station touristique Duchesnay, QC Adamo KB, Langlois KA, Brett KE, & Colley RC (2012). Young children and parental physical activity levels: findings from the canadian health measures survey. American journal of preventive medicine, 43 (2), 168-75 PMID: 22813681 .
Why Sports and Exercise are Barely Relevant and What Really Counts is Occupational and Household Activity
There is no doubt that reducing sedentariness and increasing physical activity can have enormous health benefits. This is why public health policies and health promotion bombard us with messages on how to get more active – unfortunately, much of the advise focusses on increasing engagement in recreational and volitional sports and exercise. A paper by Chuck Ratzlaff from Harvard University, published in the British Journal of Sports Medicine now suggests why attempts to encourage recreational physical activity are largely doomed to fail. This is simply not where most people’s physical activity happens – not is likely to happen. As I pointed out in yesterday’s post – most people simply do not like being physically active enough to want to do it – when given the choice, they’d much rather sit or lie down (which makes perfect evolutionary sense). It is therefore but natural, that about 80% of total daily physical activity in most people is associated with occupational and non-leisure (household chores). In his analysis, Ratzlaff of his recent population-based research measuring lifetime physical activity – sporting activity formed a small fraction of overall physical activity compared with occupational and household activity (even more so in women). Thus, “Using a rigorously developed and validated computer-guided lifetime physical activity questionnaire in a sample of 4269 Canadian adults aged 45–90 years, we found that women spent about 10 times more energy in household activity (70.5 vs 7.3 metabolic equivalent – hours/week) and 5.5 times more in occupational activity (40.5 vs 7.3 metabolic equivalent – hours/week) than in sport/recreational activity. Men spent four times more energy on occupational activity (64.9 vs 16.9 metabolic equivalent – hours/week) and 1.5 times more on household activity (28.4 vs 16.9 metabolic equivalent – hours/week) than on sport/recreation.” If anything women have gotten even more physically active than before: “Over the past several decades, women have increased occupational and sport/recreational activity, while largely maintaining high levels of household activity.” As Ratzlaff discusses, “Most studies on the relationship between physical activity and health outcomes have focused on sport/recreation and have not investigated the combined effect of sport, occupation and household activity and have not completely classified physical activity.” “A clear example is the evidence regarding physical activity in women. While women often spend 40+ hours a week at a full-time job and anywhere from 20 to 45 h a week working in the home, surveys used in many existing… Read More »
Physical Activity: From Genes to Policy
In preparation for the start of the Summer Olympics, The Lancet has dedicated virtually all of its current issue to articles on physical activity. One article by Adrian Bauman, on behalf of the “Lancet Physical Activity Series Working Group”, particularly caught my attention as it encourages us to look beyond the classical ‘ecological model’ of physical activity, which essentially looks at environmental rather than ‘biological’ determinants of physical activity. Pointing out the limitations of the model in fully explaining inter-individual variability in physical activity and the rather modest impact that interventions based on this model have so far had in terms of noticeably increasing physical activity in the general population, the authors briefly also summarize the potential ‘biological’ factors that may be important in determining who does what and how much. With regard to genetic determinants of physical activity, the authors write: “Genetics is a possible determinant of physical activity—ie, a heritable component affects activity behaviours, not just measures of fitness. Similar to other behaviours, such as eating (appetite), evidence from human and animal studies indicates that physical activity is regulated by intrinsic biological processes. Animal studies suggest that CNS mechanisms might regulate daily physical activity. Twin and family studies have shown that genetic factors contribute to variation in reported daily physical activity levels, with heritability estimates ranging from small (h2 <30%) moderate (h2=30—65%),53—58 and even high (h2=78%).” “Substantial individual differences have been noted in the acute averse and rewarding effects of physical activity, implicating genetic factors. Specifically, reward systems will be activated in individuals with above-average abilities, those who crave activity, and those who feel rewarded by accomplishing an activity; adverse effects will be reported in those who feel pain, fatigue, or even exertion. As such, candidate genes might be part of the reward systems and pain sensation.” However, they also point out that so far genome-wide studies have not yet identified a ‘robust association’ between specific genes and inter-individual differences in daily physical activity levels. The authors also discuss how evolutionary biology may relate to differences in physical activity levels. As they point out, “…many components of our physiology are adapted to a range of expected behaviour.” and ask “Is there evidence that people became physically active out of necessity and biological adaptation, and then had to reduce activity because of mechanisation and culturally and technologically induced decreases in the need for energy expenditure?” When defining levels of… Read More »
7th Obesity Research Summer Bootcamp
Faithful readers will be well aware that around this time of the year, I spend well over a week at the Canadian Obesity Network’s Summer Bootcamp, which offers 24 handpicked trainees and new professionals a remarkably intense educational event dealing with all aspects relevant to obesity research – from molecular mechanisms to epidemiology, from nutrition and exercise research to medical and surgical treatments, from policy to health economics. This camp has been a longstanding collaboration with the University of Laval (with strong input and support from the University of Alberta) and has resulted in a rather tightly knit network of over 150 young obesity professionals across Canada (and now internationally). As anyone involved in the Canadian obesity research community is well aware, it is hard not to stumble across a former ‘Bootcamper’ at scientific meetings or (increasingly) in government, health care systems and NGOs (where many of the Bootcampers have since found employment – no surprise given that they represent the ‘best-of-the-best’ among the next generation of Canadian obesity experts). Unfortunately, funding this rather exclusive but important initiative remains a challenge, which is why we have had to reduce the length of the camp from nine to seven days – making the program even more crowded – all of obesity is a lot of ground to cover by any standard. I certainly look forward to another exciting week of learning and friendships – all former Bootcampers will know exactly what I am talking about. AMS Station touristique Duchesnay, QC
Weekend Roundup, July 20, 2012
As not everyone may have a chance during the week to read every post, here’s a roundup of last week’s posts: Join the 5As Community of Practice How Much Weight Will You Gain When You Quit Smoking? Mental Health And Childhood Obesity: A Note to Policy Makers and Clinicians Obese Kids are Not Causing the Obesity Epidemic More Evidence Why BMI Alone Should Not Guide Medical Decision Making Have a great Sunday! (or what is left of it) AMS Edmonton, Alberta
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