Sedentary Behaviors,Physical Activity,and Metabolic Syndrome in Middle‐aged French Subjects

Objective: To study the relationships of time spent in sedentary occupations with the National Cholesterol Education Program—defined metabolic syndrome (MS), taking into account the habitual level of physical activity (PA). Research Methods and Procedures: This was a cross‐sectional analysis in 1902 men and 1932 women 50 to 69 years of age participating in the French Supplementation with Antioxidant Vitamins and Minerals study. We assessed past‐year PA, television watching or computer use, and reading during leisure with the Modifiable Activity Questionnaire. Subjects who performed at least 150 min/wk of moderate‐intensity PA (3 to 6 metabolic equivalent tasks) or 60 min/wk of vigorous PA (>6 metabolic equivalent tasks) were considered as meeting recommended levels. Results: The frequency of most MS components increased with time spent in front of a screen and decreased with increasing PA levels. The likelihood to have MS, adjusted for age, education, and smoking, was decreased by one‐third in subjects meeting moderate PA guidelines and by two‐thirds in subjects meeting vigorous PA recommendations [odds ratio (95% CI), 0.34 (0.17 to 0.66) in women, 0.44 (0.28 to 0.68) in men] compared with those with insufficient PA. Independently of PA levels, time spent in front of a screen was positively associated with the likelihood to have the MS in women [odds ratio (95% CI), 3.30 (2.04 to 5.34)], whereas in both sexes, no association was found with time spent reading. Discussion: The relationship of the MS with a sedentary lifestyle differs according to sex and type of sedentary occupation. These results suggest the need to assess selected indicators of sedentary behavior in preventive programs.     

Different times of day do not change heart rate variability recovery after light exercise in sedentary subjects: 24 hours Holter monitoring

Incidence of cardiovascular events follows a circadian rhythm with peak occurrence during morning. Disturbance of autonomic control caused by exercise had raised the question of the safety in morning exercise and its recovery. Furthermore, we sought to investigate whether light aerobic exercise performed at night would increase HR and decrease HRV during sleep. Therefore, the aim of this study was to test the hypothesis that morning exercise would delay HR and HRV recovery after light aerobic exercise, additionally, we tested the impact of late night light aerobic exercise on HR and HRV during sleep in sedentary subjects. Nine sedentary healthy men (age 24 ± 3 yr; height 180 ± 5 cm; weight 79 ± 8 kg; fat 12 ± 3%; mean±SD) performed 35 min of cycling exercise, at an intensity of first anaerobic threshold, at three times of day (7 a.m., 2 p.m. and 11 p.m.). R-R intervals were recorded during exercise and during short-time (60 min) and long-time recovery (24 hours) after cycling exercise. Exercise evoked increase in HR and decrease in HRV, and different times of day did not change the magnitude (p < 0.05 for time). Morning exercise did not delay exercise recovery, HR was similar to rest after 15 minutes recovery and HRV was similar to rest after 30 minutes recovery at morning, afternoon, and night. Low frequency power (LF) in normalized unites (n.u.) decreased during recovery when compared to exercise, but was still above resting values after 60 minutes of recovery. High frequency power (HF-n.u.) increased after exercise cessation (p < 0.05 for time) and was still below resting values after 60 minutes of recovery. The LF/HF ratio decreased after exercise cessation (p < 0.05 for time), but was still different to baseline levels after 60 minutes of recovery. In conclusion, morning exercise did not delay HR and HRV recovery after light aerobic cycling exercise in sedentary subjects. Additionally, exercise performed in the night did change autonomic control during the sleep. So, it seems that sedentary subjects can engage physical activity at any time of day without higher risk.     

Using a Rebound Matrix to Estimate Consumption Changes from Saving and its Environmental Impact in Japan

We investigate the extent to which Japanese people can change their consumption and the corresponding environmental impact. We propose a new analytical framework with a rebound matrix that captures the monetary flow from potential savings to their respending (referred to as rebound). A questionnaire is used to derive the matrix. On average, respondents spent 3.4 million Yen annually, resulting in 12.4 tons of carbon dioxide (CO₂) emissions in their daily lives. The survey results suggest that acceptable spending reductions would correspond to a CO₂ emissions reduction of nearly 6%. However, the CO₂ emissions would increase by nearly the same amount when the respondents respend their savable money (rebound CO₂ emissions). The annual CO₂ emissions and the annually reducible CO₂ emissions both increase with the increase in annual expenditure. Consequently, the net CO₂ emissions also increase with the increase in annual expenditure. The rebound spending is approximated using the rebound matrix. Finally, it is suggested that the net CO₂ emissions can be reduced through lifestyle changes whereby spending on energy items is reduced and the resulting savings are spent on telecommunication, clothes, shoes, education, and housing.     

Chronotype: implications for sleep quality in medical students

ABSTRACT

Medical students who suffer from poor sleep quality may be afflicted by distress. While the change of chronotype may improve sleep quality, few studies have focused on this association. The objective of this study is to analyze the effects of chronotype on sleep quality in medical students while controlling for confounding covariate factors. A cross-sectional survey on sleep quality was conducted among 5497 medical students. Sleep quality, chronotype, and lifestyle were measured according to the Pittsburgh Sleep Quality Index, Morningness-eveningness Questionnaire and Health-promoting Lifestyle Profile. Hierarchical logistic regression was conducted to analyze the influence of various factors, especially chronotype effect on sleep quality. Our results showed that the total score of sleep quality in evening-types was 5.43 ± 2.66, which was significantly higher than that in morning-types (3.88 ± 2.20, P < .001). Morning-type students (OR = 0.40, 95%CI = 0.29–0.55) and intermediate-type students (OR = 0.53, 95%CI = 0.41–0.69) had a lower risk of poor sleep quality compared to evening-types. The strongest predictor of sleep quality was chronotype while controlling for covariates (grade, gender, father’s educational level, mother’s educational level, internet addiction, mood state, midnight snack frequency, and health-promoting lifestyle profile). Based on the results, we believe that sleep quality among evening-type students may be improved by shifting to keep early hours.     

Economic and Societal Changes in China and their Effects onWater Use A Scenario Analysis

China's development over the last few decades has been characterized by high rates of economic growth, large-scale migration from rural areas to the fast-growing cities accompanied by changes in lifestyles, and steady population growth. These developments have left deep marks on resource availability and quality. In this article we conduct a scenario analysis of how lifestyle changes and other major developments might affect water resources.
China has the longest tradition in river and water resource management in the world. Its civilization has sought to control the effects of floods and drought for thousands of years and has utilized water flows for irrigation and navigation. In the last century, competing uses such as domestic, municipal, and industrial water consumption have also become reasons for the regulation of and large-scale abstraction of water.
To investigate the major changes in economy and society and their effects on the water situation in China, a set of scenarios is developed and analyzed within a structural economics framework. A hydrological model that represents water flows in the major watersheds is linked to a regional input-output model that represents socioeconomic activities in the major economic-administrative regions of China. The regional analysis shows that the North and Northwest regions are water-scarce and that lifestyle changes and technical shifts are the most important factors driving future water consumption.     

A prospectus for ethical analysis of ageing individuals' responsibility to prevent cognitive decline

As the world's population ages, governments and non‐governmental organizations in developed countries are promoting healthy cognitive ageing to reduce the rate of age‐related cognitive decline and sustain economic productivity in an ageing workforce. Recommendations from the Productivity Commission (Australia), Dementia Australia, Government Office for Science (UK), Presidential Commission for the Study of Bioethical Issues (USA), Institute of Medicine (USA), among others, are encouraging older adults to engage in mental, physical, and social activities. These lifestyle recommendations for healthy cognitive ageing are timely and well supported by scientific evidence but they make implicit normative judgments about the responsibility of ageing individuals to prevent cognitive decline. Ethical tensions arise when this individual responsibility collides with social and personal realities of ageing populations. First, we contextualize the priority given to healthy cognitive ageing within the current brain‐based medical and social discourses. Second, we explore the individual responsibility by examining the economic considerations, medical evidence and individual interests that relate to the priority given to healthy cognitive ageing. Third, we identify three key ethical challenges for policymakers seeking to implement lifestyle recommendations as an effective population‐level approach to healthy cognitive ageing. The result is a prospectus for future in‐depth analysis of ethical tensions that arise from current policy discussions of healthy cognitive ageing.     

Moral bioenhancement and agential risks: Good and bad outcomes

In Unfit for the Future, Ingmar Persson and Julian Savulescu argue that our collective existetial predicment is unprecedentedly dangerous due to climate change and terrorism. Given these global risks to human prosperity and survival, Persson and Savulescu argue that we should explore the radical possibility of moral bioenhancement in addition to cognitive enhancement. In this article, I argue that moral bioenhancements could nontrivially exacerbate the threat posed by certain kinds of malicious agents, while reducing the threat of other kinds. This introduces a previously undiscussed complication to Persson and Savulescu's proposal. In the final section, I present a novel argument for why moral bioenhancement should either be compulsory or not be made available to the public at all.     

Characterization of Households and its Implications for the Vegetation of Urban Ecosystems

Our understanding of the dynamics of urban ecosystems can be enhanced by examining the multidimensional social characteristics of households. To this end, we investigated the relative significance of three social theories of household structure—population, lifestyle behavior, and social stratification—to the distribution of vegetation cover in Baltimore, Maryland, USA. Our ability to assess the relative significance of these theories depended on fine-scale social and biophysical data. We distinguished among vegetation in three areas hypothesized to be differentially linked to these social theories: riparian areas, private lands, and public rights-of-way (PROWs). Using a multimodel inferential approach, we found that variation of vegetation cover in riparian areas was not explained by any of the three theories and that lifestyle behavior was the best predictor of vegetation cover on private lands. Surprisingly, lifestyle behavior was also the best predictor of vegetation cover in PROWs. The inclusion of a quadratic term for housing age significantly improved the models. Based on these research results, we question the exclusive use of income and education as the standard variables to explain variations in vegetation cover in urban ecological systems. We further suggest that the management of urban vegetation can be improved by developing environmental marketing strategies that address the underlying household motivations for and participation in local land management.     

Lifestyle Intervention and Fatty Acid Metabolism in Glucose‐Intolerant Subjects

Objective: Free fatty acid (FFA) oxidation is reduced in subjects with type 2 diabetes mellitus and impaired glucose tolerance (IGT). Weight reduction does not improve these impairments. Because exercise training is known to increase fatty acid (FA) oxidation, we investigated whether a combined diet and physical activity intervention program can improve FA oxidation in subjects with IGT. Research Methods and Procedures: Sixteen subjects with IGT were studied before and after 1 year of a lifestyle intervention program [nine intervention (INT) subjects, seven controls (CON)]. INT subjects received regular (i.e., every 3 months) dietary advice and were stimulated to increase their level of physical activity. Glucose tolerance, anthropometric characteristics, and substrate use at rest and during exercise were evaluated before and after 1 year. Substrate oxidation was measured at rest and during moderate intensity exercise using indirect calorimetry in combination with stable isotope infusion ([U‐¹³C]palmitate and [6, 6‐²H₂‐]glucose). Results: After 1 year, no differences were seen in substrate use at rest. During exercise, total fat and plasma FFA oxidation were slightly increased in the INT group and decreased in the CON group, with the change being significantly different (change after 1 year: INT, +2.0 ± 1.4 and +1.9 ± 0.9 μmol/kg per minute; CON, ?3.5 ± 1.6 and ?1.8 ± 0.5 μmol/kg per minute for total and plasma FFA, respectively; p < 0.05). Discussion: A combined diet and physical activity intervention program can prevent further deterioration of impaired FA oxidation during exercise in subjects with IGT.     

Relationship of body size and shape to the development of diabetes in the diabetes prevention program

Objective: We report the effects of several different measures of body size at baseline on the subsequent development of diabetes. High levels of body fat predict the onset of diabetes, but this association has not been previously reported in a large multiethnic population of overweight or obese people with impaired glucose tolerance. Research Methods and Procedures: Height, weight, waist circumference, hip circumference, and skinfolds were measured at baseline in 3234 participants enrolled in a randomized clinical trial to treat individuals with impaired glucose tolerance with placebo, metformin, or a lifestyle modification program. Cox proportional hazards models were used to assess the effect of baseline body size variables on the development of diabetes. Results: Over an average of 3.2 years in both the placebo and lifestyle groups, baseline waist circumference had the highest or second highest R² value for predicting diabetes in both sexes. Cox hazard ratios per 1 standard deviation were 1.43 and 1.49 for men in the placebo or lifestyle groups, respectively, and 1.29 and 1.53 for women in the placebo and lifestyle groups, respectively, adjusted for age and self‐reported race/ethnicity. The c‐statistic from the receiver operating characteristic curves also favored the waist circumference in men and women in the lifestyle group and men in the placebo group. No components of body size were predictive in the metformin‐treated group, and metformin compared with the placebo group was effective in preventing diabetes only in individuals with a BMI ≥35 kg/m² or a waist circumference ≥98.0 cm. Discussion: Large waist circumference was a better predictor of risk for developing diabetes than most other measures in the placebo and lifestyle groups. No baseline measure of body size or shape predicted risk of diabetes in the metformin‐treated group.