Age-related differences in physical activity levels of young adults.

Purpose: To examine age-related differences in the physical activity behaviors of young adults.

Methods: We examined rates of participation in vigorous- and moderate-intensity leisure-time activity and walking, as well as an index of physical activity sufficient for health benefits in three Australian cross-sectional samples, for the age ranges of 18–19, 20–24, and 25–29 yr. Data were collected in 1991, 1996, and 1997/8.

Results: There was at least a 15% difference in vigorous-intensity leisure-time physical activity from the 18–19 yr to the 25–29 yr age groups, and at least a 10% difference in moderate-intensity leisure-time physical activity. For the index of sufficient activity there was a difference between 9 and 21% across age groups. Differences in rates of walking were less than 8%. For all age groups, males had higher rates of participation for vigorous and moderate-intensity activity than did females, but females had much higher rates of participation in walking than males. Age-associated differences in activity levels were more apparent for males.

Conclusions: Promoting walking and various forms of moderate-intensity physical activities to young adult males, and encouraging young adult females to adopt other forms of moderate-intensity activity to complement walking may help to ameliorate decreases in physical activity over the adult lifespan.

Energy use in relocatable classrooms

A nine month study of four relocatables in Melbourne, each containing two classrooms and retro-fitted with various models of small reverse cycle air conditioner, found that the energy used for heating these "temporary" classrooms was only 19-20% of the energy used in permanent classrooms fitted with individual gas heaters. The energy delivered to the relocatables was calculated to be 20-27% less than that delivered to the permanent classrooms, when equipment efficiencies were considered. The reasons for this difference are explored in this paper. It was found superior insulation levels and reduced comfort levels appear to be the key factors responsible for the reduced annual heating energy demand. CO² emissions for the AC units in heating mode were calculated to be 16% greater than for individual gas heaters. The AC units were also used for cooling and on average the total annual energy consumption for heating and cooling was found to be just over 700 kWh or 11.6 kWh ^-2 m.

Reducing unhealthy weight gain in children through community capacity−building: results of a quasi−experimental intervention program, Be Active Eat Well

Background:
Be Active Eat Well (BAEW) was a multifaceted community capacity-building program promoting healthy eating and physical activity for children (aged 4–12 years) in the Australian town of Colac.
Objective:
To evaluate the effects of BAEW on reducing children's unhealthy weight gain.
Methods:
BAEW had a quasi-experimental, longitudinal design with anthropometric and demographic data collected on Colac children in four preschools and six primary schools at baseline (2003, n=1001, response rate: 58%) and follow-up (2006, n=839, follow-up rate: 84%). The comparison sample was a stratified random selection of preschools (n=4) and primary schools (n=12) from the rest of the Barwon South Western region of Victoria, with baseline assessment in 2003–2004 (n=1183, response rate: 44%) and follow-up in 2006 (n=979, follow-up rate: 83%).
Results:
Colac children had significantly lower increases in body weight (mean: -0.92 kg, 95% CI: -1.74 to -0.11), waist (-3.14 cm, -5.07 to -1.22), waist/height (-0.02, -0.03 to -0.004), and body mass index z-score (-0.11, -0.21 to -0.01) than comparison children, adjusted for baseline variable, age, height, gender, duration between measurements and clustering by school. In Colac, the anthropometric changes were not related to four indicators of socioeconomic status (SES), whereas in the comparison group 19/20 such analyses showed significantly greater gains in anthropometry in children from lower SES families. Changes in underweight and attempted weight loss were no different between the groups.
Conclusions:
Building community capacity to promote healthy eating and physical activity appears to be a safe and effective way to reduce unhealthy weight gain in children without increasing health inequalities.

Positive development in emerging adulthood

Positive functioning in the developmental period of emerging adulthood has received little investigation. The current study investigated components of positive development using confirmatory factor analysis of Australian Temperament Project data collected from 1,158 young adults aged 19-20 years. Positive development constructs that have been theoretically conceptualised were examined to test core concepts. Five first-order constructs were identified in this sample: Civic Action and Engagement, Social Competence, Life Satisfaction, Trust and Tolerance of Others, and Trust in Authorities and Organisations. A second-order positive development factor defined by these constructs provided good fit for the data. This model of positive development in emerging adulthood can provide an outcome measure that can then be used to investigate the developmental processes and pathways involved.

Differentiating three conceptualisations of the relationship between positive development and psychopathology during the transition to adulthood

The transition to adulthood is characterised by both great potential for positive change and a relatively high incidence of problem outcomes. A multidimensional model of positive development during the transition to adulthood (at 19-20 years) has recently been proposed. However, an unresolved question regarding the nature of positive development during this time is how best to conceptualise its relationship to psychopathology. We drew on data from 1158 participants in the Australian Temperament Project, a large longitudinal community-based study that has followed young people's psychosocial adjustment from infancy to early adulthood. Using structural equation modelling, we compared three models reflecting different conceptualisations of the relationship between positive development and psychopathology. The results suggest that positive development and psychopathology are best modelled as separate but correlated constructs. Hence, development in one domain is likely to influence the other, although separate and specific developmental pathways are also likely to be operating.

Recommendations for improved data processing from expired gas analysis indirect calorimetry

There is currently no universally recommended and accepted method of data processing within the science of indirect calorimetry for either mixing chamber or breath-by-breath systems of expired gas analysis. Exercise physiologists were first surveyed to determine methods used to process oxygen consumption ([OV0312]O 2) data, and current attitudes to data processing within the science of indirect calorimetry. Breath-by-breath datasets obtained from indirect calorimetry during incremental exercise were then used to demonstrate the consequences of commonly used time, breath and digital filter post-acquisition data processing strategies. Assessment of the variability in breath-by-breath data was determined using multiple regression based on the independent variables ventilation (VE), and the expired gas fractions for oxygen and carbon dioxide, FEO 2 and FECO2, respectively. Based on the results of explanation of variance of the breath-by-breath [OV0312]O2 data, methods of processing to remove variability were proposed for time-averaged, breath-averaged and digital filter applications. Among exercise physiologists, the strategy used to remove the variability in sequential [OV0312]O2 measurements varied widely, and consisted of time averages (30 sec [38%], 60 sec [18%], 20 sec [11%], 15 sec [8%]), a moving average of five to 11 breaths (10%), and the middle five of seven breaths (7%). Most respondents indicated that they used multiple criteria to establish maximum [OV0312]O 2 ([OV0312]O2max) including: the attainment of age-predicted maximum heart rate (HRmax) [53%], respiratory exchange ratio (RER) >1.10 (49%) or RER >1.15 (27%) and a rating of perceived exertion (RPE) of >17, 18 or 19 (20%). The reasons stated for these strategies included their own beliefs (32%), what they were taught (26%), what they read in research articles (22%), tradition (13%) and the influence of their colleagues (7%). The combination of VE, FEO 2 and FECO2 removed 96-98% of [OV0312]O2 breath-by-breath variability in incremental and steady-state exercise [OV0312]O2 data sets, respectively. Correction of residual error in [OV0312]O2 datasets to 10% of the raw variability results from application of a 30-second time average, 15-breath running average, or a 0.04 Hz low cut-off digital filter. Thus, we recommend that once these data processing strategies are used, the peak or maximal value becomes the highest processed datapoint. Exercise physiologists need to agree on, and continually refine through empirical research, a consistent process for analysing data from indirect calorimetry.

Cardiovascular disease self-management: pilot testing of an mHealth healthy eating program

Cardiac rehabilitation (CR) is crucial in the management of cardiovascular disease (CVD), yet attendance is poor. Mobile technology (mHealth) offers a potential solution to increase reach of CR. This paper presents two development studies to determine mobile phone usage in adults with CVD and to evaluate the acceptability of an mHealth healthy eating CR program. Methods: CR attendees were surveyed to determine mobile phone usage rates. A second single-subject pilot study investigated perceptions of a 4-week theory-based healthy eating mHealth program and explored pre-post changes in self-efficacy. Results: 74 adults with CVD completed the survey (50/74 male; mean age 63 ± 10). Nearly all had mobile phones (70/74; 95%) and used the Internet (69/74; 93%), and most were interested in receiving CR by text message (57/74; 77%). 20 participants took part in the healthy eating pilot study. Participants read all/most of the text messages, and most (19/20) thought using mobile technology was a good way to deliver the program. The website was not widely used as visiting the website was reported to be time consuming. Exploratory t-tests revealed an increase in heart healthy eating self-efficacy post program, in particular the environmental self-efficacy subset (Mean = 0.62, SD = 0.74, p = 0.001). Conclusions: Text messaging was seen as a simple and acceptable way to deliver nutrition information and behavior change strategies; however, future research is needed to determine the effectiveness of such programs.