Physical Inactivity from the Viewpoint of Evolutionary Medicine

Sedentarism and Chronic Health Problems

Increased mechanization and technological advances have simplified our lives on the one hand and increased sedentary behaviors on the other hand, paving the way for emerging global health concerns, i.e., sedentarism, which could be the leading cause of all major chronic health problems worldwide. Sedentarism is a habitual behavior of choosing and indulging in low-energy expenditure activities (≤1.5 metabolic equivalents), such as chairtype (sitting, studying, traveling) or screen-type activities (TV, computers, mobile). With technological advancements, there is a significant transition in the lifestyles of people from being active (walking) to being more deskbound (sitting). Prolonged sitting can have unintended consequences for health with sitting time >7 h/d, leading to a 5% increase in all-cause mortality with each additional hour spent sitting (i.e., +7 h/d), while considering physical activity levels. This review will highlight how sedentarism is emerging as a major risk factor for the rising incidence of non-communicable diseases, especially among young adults and adults. Chronic diseases, such as obesity, diabetes, coronary heart disease, and cancer, are the leading causes of death worldwide. Hence, there is an urgent need for collective action to mitigate the burgeoning public health crisis posed by sedentarism in the 21st century. This paper intends to set in motion a call for all policymakers and public health professionals placed nationally or internationally to reach a consensus on ending sedentarism and provide viable resolutions for effective management of excessive sedentary behaviors and healthy adoption and maintenance of active lifestyles among individuals of all age groups.

Take a load off: skeletal implications of sedentism in the feet of modern body donors

Background and Objectives

Modern biocultural environments continue to place selective pressures on our skeletons. In the past century, a major cultural pressure has been the rise in sedentism. However, studies considering the effects of sedentism on the foot have largely considered pathological changes to the gross foot without particular regard for the pedal skeleton. To address this gap in the literature, temporal trends in the development of osteoarthritis and entheseal changes on the tarsals and metatarsals were analyzed in the context of biodemographic data for recent modern humans.

Methodology

The sample utilized for this project is comprised of 71 individuals from the William M. Bass Donated Skeletal Collection, with birth years ranging from 1909 to 1993. Temporal trends in osteoarthritis and entheseal changes were determined via ANCOVA, using year of birth as the explanatory variable and biodemographic variables (age, sex, stature, body mass index and tibial robusticity) as covariates.

Results

Results indicate that entheseal changes and osteoarthritis have decreased over time, and these trends are statistically significant. Temporal trends in pedal entheseal changes and osteoarthritis vary by sex.

Conclusions and Implications

The increase in sedentary behavior over time has usually been framed as a net negative for human health and well-being. However, considered in isolation, the decrease in entheseal changes and osteoarthritis presented here might be considered a positive development as they suggest overall less stress on the modern human foot. This study also has the potential to inform the health sciences and general public about biocultural contributors to modern foot health.

Translation, Cross-Cultural Adaptation, and Validation of the Persian Version of the Lifetime Total Physical Activity Questionnaire

BACKGROUND

This study aimed to translate and cross-culturally adapt the Lifetime Total Physical Activity Questionnaire (LTPAQ) for use in Persian-speaking countries as well as evaluate its validity and reliability.

METHODS

There were 3 stages to this study. First, a forward-backward translation method was used to develop a Persian version of the LTPAQ. In the second stage, the Persian version of the LTPAQ was evaluated for its face validity and content validity. Finally, test-retest reliability and known-group validity were assessed. The LTPAQ has occupational and volunteer activities, including travel to work, exercise and sports, and household activities. Frequency, duration, and estimated metabolic costs of activities with light, moderate, and heavy intensities were used to calculate the metabolic equivalent of each domain during life (in metabolic equivalent-hour/week). Metabolic equivalents of each domain and in total were used to evaluate the reliability and validity of the questionnaire.

RESULTS

In total, 60 people (41.7% females) with a mean age of 33.9 (SD = 11.5) years participated in this study. All domains showed excellent test-retest reliability (intraclass correlation coefficient > .9). All items had content validity indexes higher than 0.85. In addition, males had significantly higher physical activity levels than females (P = .022), indicating the known-group validity of the questionnaire.

CONCLUSIONS

The LTPAQ was translated into Persian and trans-culturally adapted. This study indicates that the Persian version of the LTPAQ has adequate reliability and validity and can be utilized in future studies to assess physical activity in the Persian population.

Climate change, 24-hour movement behaviors, and health: a mini umbrella review

BACKGROUND

The worsening climate change and alarming prevalence of communicable and non-communicable diseases continue to threat human life and existence. Accumulating evidence suggests that favorable patterns of 24-h movement behaviors, high physical activity, low sedentary behavior, and adequate sleep, may positively contribute to achieving dual benefits of climate change mitigation and disease prevention. The purposes of this mini umbrella review were to summarize the most up-to-date, high-level evidence exploring the relationships between climate change, 24-h movement behaviors, and health and elaborate on the mechanisms linking the three variables of interest.

METHODS

A systematic search of electronic databases was performed in PubMed and Google Scholar during March-October 2020. Inclusion criteria were: (1) systematic review; (2) reviewed relationships between climate change and movement behaviors and/or health in any directions; (3) written in English; (4) published in 2010-2020. Narrative synthesis was conducted to highlight the main relationships observed and address the current state of knowledge and priorities for future research. In order to illustrate the potential mechanisms between climate change, movement behaviors, and health, the main results from included systematic reviews were summarized and a conceptual framework was developed for future research.

RESULTS

Based on the evidence from eight systematic reviews published in the past decade, multi-directional (i.e., uni-, bi-, or U-shaped) links were observed between climate change and varying human health outcomes. However, little is understood about the association between climate change and 24-h movement behaviors. Two reviews suggested the negative impact of climate change on sleep and bi-directional relationships between climate change and physical activity/sport. One review included two studies suggesting the unfavorable impact of climate change on sedentary behavior; however, the evidence was limited. Finally, no reviews examined the mechanisms by which climate change, movement behaviors, and health impact one another. Based on the findings of this mini umbrella review, a conceptual framework is proposed that could guide future work to unpack mechanisms between climate change, movement behaviors, and health.

CONCLUSIONS

This mini umbrella review highlights the importance of better understanding the mechanisms between climate change, movement behaviors, and health in developing effective mitigation and adaptation strategies to climate change, while paying close attention to vulnerable countries/communities/population groups.

The brown bear as a translational model for sedentary lifestyle-related diseases

Sedentary lifestyle accelerates biological ageing, is a major risk factor for developing metabolic syndrome and is associated with cardiovascular disease, diabetes mellitus, kidney failure, sarcopenia and osteoporosis. In contrast to the linear path to worsening health in humans with metabolic syndrome, brown bears have developed a circular metabolic plasticity enabling these animals to tolerate obesity and a 'sedentary lifestyle' during hibernation and exit the den metabolically healthy in spring. Bears are close to humans physiology wise, much closer than rodents, the preferred experimental animals in medical research, and may better serve as translational model to develop treatments for lifestyle-related diseases. In this review, aspects of brown bear hibernation survival strategies are outlined and conceivable experimental strategies to learn from bears are described.

Dietary intakes and obesity of Malaysian adults

BACKGROUND/OBJECTIVES

Over the past few decades, Malaysia has been experiencing an increased prevalence of overweight and obesity that threatens the health of Malaysians. Poor dietary intake is one of the major contributors to the development of obesity and many non-communicable diseases. The dietary intakes of adults in Malaysia were assessed to determine the association between the dietary intake variables and the body mass index (BMI) and waist circumference (WC) measurements. This study examined whether the dietary intake achieved the recommended nutritional guidelines and compared the intakes between both sexes.

SUBJECTS/METHODS

The height, weight, and WC of four-hundred-and-ninety adults (n = 490) in Malaysia were measured using standard procedures. The three-day 24-hour dietary recalls were conducted on 422 out of the 490 adults and their dietary intakes were evaluated in detail. The selected dietary intake variables were used to determine the associations with the obesity indicators.

RESULTS

Among the participants, 52.8% were overweight or obese. After data analysis, the mean energy intake was 1,550 kcal/day, in which male participants had a significantly higher energy and macronutrients intake than females. Protein consumption and its percentage of energy contribution exceeded the recommended range. The consumption of fruits, vegetables, and milk and milk products were lower than the recommended number of servings for a healthy diet. The male participants consumed significantly more servings of carbohydrate-based foods, meat, and fats, oils, and sweets than females. Among the selected dietary intake variables, only the carbohydrate intake was negatively associated with the BMI (Estimate b = −0.008) and WC measurements (Estimate b = −0.019) after adjusting for covariates.

CONCLUSIONS

This study evaluated the dietary intakes of a sample of Malaysian adults and its association with the obesity indicators. The results highlight the need for improvements and modifications of the dietary intake of Malaysians to reduce the overweight and obesity rates.

Predictors of Back Pain in Firefighters

The purpose of this study was to identify variables—that is, demographic factors (age, history of back pain, body mass index [BMI], and waist circumference), occupational stress, job satisfaction, perceived supervisor support, and physical fitness—that predict back pain in firefighters. Firefighters, an occupational group at high risk for back injury, perform many job tasks under hazardous work conditions. A nonexperimental, correlational design was used to study a convenience sample of 298 male firefighters who completed study questionnaires. Almost one third (30.20%) of the firefighters reported current back pain. The set of factors that predicted current back pain in firefighters included occupational stress, age, history of back pain, and BMI—pseudo R2 = .351. Further studies should validate the model and explore relationships among perceived supervisor support, occupational stress, and job satisfaction in other occupational groups, including nurses and police officers.