Physical Activity and Excess Body Weight and Adiposity for Adults. American College of Sports Medicine Consensus Statement.

ABSTRACT: Excessive body weight and adiposity contribute to many adverse health concerns. The American College of Sports Medicine (ACSM) recognizes that the condition of excess body weight and adiposity is complex, with numerous factors warranting consideration. The ACSM published a position stand on this topic in 2001 with an update in 2009, and a consensus paper on the role of physical activity in the prevention of weight gain in 2019. This current consensus paper serves as an additional update to those prior ACSM position and consensus papers. The ACSM supports the inclusion of physical activity in medical treatments (pharmacotherapy, metabolic and bariatric surgery) of excess weight and adiposity, as deemed to be medically appropriate, and provides perspectives on physical activity within these therapies. For weight loss and prevention of weight gain, the effects may be most prevalent when physical activity is progressed in an appropriate manner to at least 150 min·wk-1 of moderate-intensity physical activity, and these benefits occur in a dose-response manner. High-intensity interval training does not appear to be superior to moderate-to-vigorous physical activity for body weight regulation, and light-intensity physical activity may also be an alternative approach provided it is of sufficient energy expenditure. Evidence does not support that any one single mode of physical activity is superior to other modes for the prevention of weight gain or weight loss, and to elicit holistic health benefits beyond the effects on body weight and adiposity, multimodal physical activity should be recommended. The interaction between energy expenditure and energy intake is complex, and the effects of exercise on the control of appetite are variable between individuals. Physical activity interventions should be inclusive and tailored for sex, self-identified gender, race, ethnicity, socioeconomic status, age, and developmental level. Intervention approaches can also include different forms, channels, and methods to support physical activity.

Impact of physical activity, diet quality and stress on cardiometabolic health in school employees.

Among school employees, it has been reported that poor physical and mental health, as well as high stress and large workloads, have resulted in high absenteeism and low retention. The consequences of unhealthy behaviors and stress can extend to students, impacting academic achievement and school costs. Our objective was to examine the impact of school employees' physical activity (PA), diet quality and perceived occupational stress on cardiometabolic health, and explore how stress may influence the impact of PA and diet on health. In this cross-sectional study, employees from lower-income Massachusetts schools participated in Wellness Assessments (2015-2016), including measured height, weight, and lipids [total (TC), high-density lipoprotein (HDL-C), low-density lipoprotein (LDL-C)]. Self-administered surveys were used to collect demographic, stress, PA and 24-hour food intake data. Linear regression models were used to examine the relationship among health behaviors (PA and diet), stress and cardiometabolic health. An interaction between stress and health behaviors was also explored. Seventy-four employees (66% teachers) participated. Overweight/obesity (mean BMI: 25.6 kg/m2), high TC and LDL-C were observed in 47%, 4%, and 34%, respectively, and moderate-to-vigorous PA (MVPA) was low (median: 17 min/day). Positive associations were identified between MVPA and cardiometabolic health, but not diet. The effect of MVPA on BMI was modified by stress (p-for-interaction = 0.001), with higher levels of stress associated with a diminished protective association between MVPA and BMI. Higher levels of PA were associated with more favorable cardiometabolic health, with increasing levels of stress minimizing the beneficial effect of PA on BMI.

Pet Ownership and Cancer Risk in the Women's Health Initiative.

BACKGROUND: Pet ownership and cancer are both highly prevalent in the United States. Evidence suggests that associations may exist between this potentially modifiable factor and cancer prevention, though studies are sparse. The present report examined whether pet ownership (dog, cat, or bird) is associated with lower risk for total cancer and site-specific obesity-related cancers. METHODS: This was a prospective analysis of 123,560 participants (20,981 dog owners; 19,288 cat owners; 1,338 bird owners; and 81,953 non-pet owners) enrolled in the Women's Health Initiative observational study and clinical trials. Cox proportional hazards models were used to estimate HR and 95% confidence intervals for the association between pet ownership and cancer, adjusted for potential confounders. RESULTS: There were no significant relationships between ownership of a dog, cat, or bird and incidence of cancer overall. When site-specific cancers were examined, no associations were observed after adjustment for multiple comparisons. CONCLUSION: Pet ownership had no association with overall cancer incidence. IMPACT: This is the first large epidemiologic study to date to explore relationships between pet ownership and cancer risk, as well as associated risks for individual cancer types. This study requires replication in other sizable, diverse cohorts. Cancer Epidemiol Biomarkers Prev; 25(9); 1311-6. ©2016 AACR.

The effect of a communications campaign on middle school students' nutrition and physical activity: results of the HEALTHY study.

The HEALTHY Study was a 3-year school-based intervention designed to change the behaviors of middle school students to reduce their risk for developing type 2 diabetes mellitus. This report examines the relation between exposure to communications campaign materials and behavior change among students in the HEALTHY intervention schools. Using data from campaign tracking logs and student interviews, the authors examined communications campaign implementation and exposure to the communications campaign as well as health behavior change. Campaign tracking documents revealed variability across schools in the quantity of communications materials disseminated. Student interviews confirmed that there was variability in the proportion of students who reported receiving information from the communication campaign elements. Correlations and regression analysis controlling for semester examined the association between campaign exposure and behavior change across schools. There was a significant association between the proportion of students exposed to the campaign and the proportion of students who made changes in health behavior commensurate with study goals. The results suggest that, in the context of a multifaceted school-based health promotion intervention, schools that achieve a higher rate of exposure to communication campaign materials among the students may stimulate greater health behavior change.

Dietary intervention of flaxseed: effect on serum levels of IGF-1, IGF-BP3, and C-peptide.

Higher levels of insulin and insulin-like growth factor 1 (IGF-1) increase cancer risk by stimulating cell proliferation and increasing survival of DNA-damaged cells through antiapoptotic mechanisms. Laboratory studies suggest that flaxseed added to the diet may lower circulating levels of insulin and IGF-1, but there is limited information on the effects of dietary flaxseed on these biomarkers of cancer risk in humans. The aim of this study was to determine the effect of flaxseed supplementation in postmenopausal women on serum levels of insulin-like growth factor 1 (IGF-1), insulin-like growth factor binding protein 3 (IGF-BP3), and C-peptide, a marker of insulin production. Forty-eight postmenopausal women participated in this 12-wk baseline to postintervention study. Participants were asked to consume 7.5 g per day of ground flaxseed for 6 wk and 15 g per day for an additional 6 wk. No significant changes were observed in blood levels of IGF-1, IGF-BP3, or C-peptide over the study intervention. Flaxseed supplementation did not impact circulating levels of IGF-1, IGF-BP3, or C-peptide. Longer duration of intake may be necessary to observe changes in these biomarkers of cancer risk.

The effects of the HEALTHY study intervention on middle school student dietary intakes.

BACKGROUND: The HEALTHY study was designed to respond to the alarming trends in increasing rates of overweight, obesity, and type 2 diabetes mellitus in youth. The objective of this analysis was to examine the effects of the HEALTHY study on student self-reported dietary intakes (energy, macronutrients and grams consumed of selected food groups). METHODS: HEALTHY was a cluster-randomized study in 42 public middle schools. Students, n=3908, self-reported dietary intake using the Block Kids Questionnaire. General linear mixed models were used to analyze differences in dietary intake at the end of the study between intervention and control schools. RESULTS: The reported average daily fruit consumption was 10% higher at the end of the study in the intervention schools than in the control schools (138 g or approximately 2 servings versus 122 g, respectively, p=0.0016). The reported water intake was approximately 2 fluid ounces higher in the intervention schools than in the control (483 g versus 429 g respectively; p=0.008). There were no significant differences between intervention and control for mean intakes of energy, macronutrients, fiber, grains, vegetables, legumes, sweets, sweetened beverages, and higher- or lower-fat milk consumption. CONCLUSION: The HEALTHY study, a five-semester middle school-based intervention program that integrated multiple components in nutrition, physical education, behavior change, and social marketing-based communications, resulted in significant changes to student's reported fruit and water intake. Subsequent interventions need to go beyond the school environment to change diet behaviors that may affect weight status of children.

HEALTHY intervention: fitness, physical activity, and metabolic syndrome results.

PURPOSE: This study aimed to assess the effect of the HEALTHY intervention on the metabolic syndrome (Met-S), fitness, and physical activity levels of US middle-school students. METHODS: Cluster randomized controlled trial conducted in 42 (21 intervention) US middle schools. Participants were recruited at the start of sixth grade (2006) when baseline assessments were made, with post-assessments made 2.5 yr later at the end of eighth grade (2009). The HEALTHY intervention had four components: 1) improved school food environment, 2) physical activity and eating educational sessions, 3) social marketing, and 4) revised physical education curriculum. Met-S risk factors, 20-m shuttle run (fitness), and self-reported moderate to vigorous physical activity (MVPA) were assessed at each time point. Ethnicity and gender were self-reported. Obesity status (normal weight, overweight, or obese) was also assessed. RESULTS: At baseline, 5% of the participants were classified with Met-S, with two-thirds of the males and one-third of the females recording below average baseline fitness levels. Control group participants reported 96 min of MVPA at baseline with 103 min reported by the intervention group. There were no statistically significant (P < 0.05) differences in Met-S, fitness, or MVPA levels at the end of the study after adjustment for baseline values and confounders. There were no differences in any ethnic, obesity, or ethnic × obesity subgroups for either gender. CONCLUSIONS: The HEALTHY intervention had no effect on the Met-S, fitness, or physical activity levels. Approaches that focus on how to change physical activity, fitness, and Met-S using nonschool or perhaps in addition to school based components need to be developed.

Effect of flaxseed consumption on urinary levels of estrogen metabolites in postmenopausal women.

Flaxseed is a rich source of dietary lignans. It has been hypothesized that lignans may decrease breast cancer risk through modulation of endogenous hormone levels. The aim of this study was to determine the effect of flaxseed supplementation on urinary levels of estrogen metabolites that may be involved in the development of breast cancer. Forty-three postmenopausal women participated in this 12-wk preintervention-postintervention study. Participants consumed 7.5 g/day of ground flaxseed for 6 wk, followed by 15 g/day for an additional 6 wk. The mean urinary level of 16alpha -hydroxyestrone (16alpha -OHE1) was higher at the end of 12 wk compared to baseline (change of 1.32 ug/day, P = 0.02). There was no significant change in 2-OHE1 excretion. The mean urinary level of the 2-OHE1/16alpha -OHE1 ratio was lower at the end of 12 wk compared to baseline (change of -1.1, P = 0.02). Mean urinary excretion of 2-methoxyestradiol was also lower at 12 wk than at baseline (P = 0.03). Based on the current paradigm of the effects of estrogen metabolism on breast cancer risk, the regimen of dietary flaxseed intake used in this study did not appear to favorably alter breast cancer risk through shifts in estrogen metabolism pathways in postmenopausal women.

Vitamin K supplementation does not significantly impact bone mineral density and biochemical markers of bone in pre- and perimenopausal women.

Because of its role in osteoblastic metabolism, vitamin K has been studied with respect to bone. However, there has been limited research examining the influence of long-term vitamin K supplementation on bone mineral density (BMD). Therefore, the purpose of this study was to assess the impact of 6 months of vitamin K supplementation on BMD and biomarkers of bone in pre- and perimenopausal women. Based on previous work, we hypothesized that vitamin K would improve BMD and biochemical markers of bone formation. A double-blind, placebo-controlled, randomized trial is an effective way to study the impact of long-term supplementation. Thus, 14 pre- and perimenopausal women, 25 to 50 years of age, were randomly assigned to an experimental group (E) that received 600 microg/d of vitamin K in the form of phylloquinone (K(1)) or a control group (C) that received identical-looking placebo tablets. Regional BMD and percent body fat, measured by dual-energy x-ray absorptiometry, and serum osteocalcin and urinary N-telopeptide levels were all assessed at 0, 3, and 6 months. When BMD was measured across time, C had a significant increase (P = .011) in greater trochanter BMD compared to E. The E group had a nonsignificant increase (P = .067) in shaft BMD compared to the C group. There was no significant difference between E and C in serum osteocalcin concentrations over time. Urinary N-telopeptide levels increased significantly over time in E compared to C (P = .008). Six months of 600 microg/d vitamin K(1) supplementation did not improve regional BMD in this group of pre- and perimenopausal women.

Effect of dietary flaxseed on serum levels of estrogens and androgens in postmenopausal women.

Flaxseed is a rich source of dietary lignans. Experimental studies suggest lignans may exert breast cancer preventive effects through hormonal mechanisms. Our aim was to study the effects of flaxseed on serum sex hormones implicated in the development of breast cancer. Forty-eight postmenopausal women participated in a 12-wk preintervention-postintervention study. Participants consumed 7.5 g/day of ground flaxseed for the first 6 wk and 15.0 grams/day for an additional 6 wk. Nonsignificant declines were noted over the 12 wk (95% confidence intervals) for estradiol (pg/ml), estrone (pg/ml), and testosterone (pg/ml): -4.4 (-12.6 to 3.9), -3.3 (-7.7 to 1.2), -4.7 (-17.8 to 8.5), respectively. Changes tended to be more pronounced in overweight/obese women, particularly for estrone (-6.5, -11.9 to -1.2; P = .02). Our results suggest that dietary flaxseed may modestly lower serum levels of sex steroid hormones, especially in overweight/obese women.

Effect of carbohydrate intake during recovery from eccentric exercise on interleukin-6 and muscle-damage markers.

The purpose of this investigation was to determine whether carbohydrate supplementation during the first 2 d postexercise recovery influenced the inflammation (IL-6, C-reactive protein [CRP], and cortisol) and muscle-damage responses. Eight participants performed a high-force eccentric elbow-flexion exercise to induce muscle soreness and inflammation and then consumed carbohydrate (0.25 g.kg(-1).h(-1)) or an equal volume of placebo during hours 0-12 and 24-36 postexercise in a double-blind, crossover protocol. Muscle soreness; midbrachial arm circumference; blood glucose, IL-6, CRP, cortisol, and creatine-kinase (CK) activity; and maximal force production were measured preexercise and 4, 8, 12, 24, 48, and 120 h postexercise. Plasma IL-6 increased, F(5) = 5.27, P < 0.05, 8 h postexercise, with no difference between carbohydrate and placebo conditions. Changes in muscle soreness, arm circumference, strength, and serum CK activity were consistent with small amounts of muscle damage and did not differ between conditions. The authors conclude that carbohydrate supplementation during recovery from soreness-inducing exercise does not influence the delayed IL-6 response temporally linked to inflammation or indications of muscle damage. Thus, increased carbohydrate consumption at levels consistent with recommendations for replenishing glycogen stores does not impair or promote the immune and muscle responses.