Overweight and obesity have high prevalence¹ and are associated with numerous health conditions.² Interventions emphasizing both diet and physical activity are effective for weight loss, resulting in 6-month weight loss of 8% to 10% of initial weight.³ However, challenges remain to sustaining weight loss long-term.³

Research from JAMA — Effect of Exercise Duration and Intensity on Weight Loss in Overweight, Sedentary Women — A Randomized Trial — ContextA higher duration and intensity of exercise may improve long-term weight loss.ObjectiveTo compare the effects of different durations and intensities of exercise on 12-month weight loss and cardiorespiratory fitness.Design, Setting, and ParticipantsRandomized trial conducted from January 2000 through December 2001 involving 201 sedentary women (mean [SD] age, 37.0 [5.7] years; mean [SD] body mass index, 32.6 [4.2]) in a university-based weight control program.InterventionParticipants were randomly assigned to 1 of 4 exercise groups (vigorous intensity/high duration; moderate intensity/high duration; moderate intensity/moderate duration; or vigorous intensity/moderate duration) based on estimated energy expenditure (1000 kcal/wk vs 2000 kcal/wk) and exercise intensity (moderate vs vigorous). All women were instructed to reduce intake of energy to between 1200 and 1500 kcal/d and dietary fat to between 20% and 30% of total energy intake.Main Outcome MeasuresBody weight, cardiorespiratory fitness, and exercise participation.ResultsAfter exclusions, 184 of 196 randomized participants completed 12 months of treatment (94%). In intention-to-treat analysis, mean (SD) weight loss following 12 months of treatment was statistically significant (P <.001) in all exercise groups (vigorous intensity/high duration = 8.9 [7.3] kg; moderate intensity/high duration = 8.2 [7.6] kg; moderate intensity/moderate duration = 6.3 [5.6] kg; vigorous intensity/moderate duration = 7.0 [6.4] kg), with no significant difference between groups. Mean (SD) cardiorespiratory fitness levels also increased significantly (P = .04) in all groups (vigorous intensity/high duration = 22.0% [19.9%]; moderate intensity/high duration = 14.9% [18.6%]; moderate intensity/moderate duration = 13.5% [16.9%]; vigorous intensity/moderate duration = 18.9% [16.9%]), with no difference between groups. Post hoc analysis revealed that percentage weight loss at 12 months was associated with the level of physical activity performed at 6 and 12 months. Women reporting less than 150 min/wk had a mean (SD) weight loss of 4.7% [6.0%]; inconsistent (other) pattern of physical activity, 7.0% [6.9%]; 150 min/wk or more, 9.5% [7.9%]; and 200 min/wk or more of exercise, 13.6% [7.8%].ConclusionsSignificant weight loss and improved cardiorespiratory fitness were achieved through the combination of exercise and diet during 12 months, although no differences were found based on different exercise durations and intensities in this group of sedentary, overweight women.

Medically treated injuries have been shown to increase with increasing body mass index (BMI). Information is lacking on the frequency and type of injuries and illnesses among overweight and obese adults who engage in regular physical activities as part of weight loss or weight gain prevention programs.

More than 65% of adults in the United States are overweight,¹ which is a public health concern because of its association with numerous chronic diseases.² Among obese adults, long-term weight loss and prevention of weight regain have been less than desired.^3,4 Therefore, there is a need for more effective interventions.

JAKICIC, J. M., M. MARCUS, K. I. GALLAGHER, C. RANDALL, E. THOMAS, F. L. GOSS, and R. J. ROBERTSON. Evaluation of the SenseWear Pro Armband™ to Assess Energy Expenditure during Exercise. Med. Sci. Sports Exerc., Vol. 36, No. 5, pp. 897–904, 2004.Purpose:To assess the accuracy of the SenseWea

Purpose: This study aimed to conduct a systematic literature review to determine whether physical activity episodes of <10 min in duration have health-related benefits or, alternatively, if the benefits are only realized when the duration of physical activity episodes is ≥10 min. Methods: The primary literature search was conducted for the 2018 Physical Activity Guidelines Advisory Committee Report and encompassed literature through June 2017, with an additional literature search conducted to include literature published through March 2018 for inclusion in this systematic review. Results: The literature review identified 29 articles that were pertinent to the research question that used either cross-sectional, prospective cohort, or randomized designs. One prospective cohort study (N = 4840) reported similar associations between moderate to vigorous physical activity (MVPA) and all-cause mortality when examined as total MVPA, MVPA in bouts ≥5 min in duration, or MVPA in bouts ≥10 min in duration. Additional evidence was identified from cross-sectional and prospective studies to support that bouts of physical activity <10 min in duration are associated with a variety of health outcomes. Randomized studies only examined bouts of physical activity ≥10 min in duration. Conclusions: The current evidence, from cross-sectional and prospective cohort studies, supports that physical activity of any bout duration is associated with improved health outcomes, which includes all-cause mortality. This may suggest the need for a contemporary paradigm shift in public health recommendations for physical activity, which supports total MVPA as an important lifestyle behavior regardless of the bout duration.