Weight‐Loss Practices and Asthma: Findings from the Behavioral Risk Factor Surveillance System

Objective: To describe weight‐control practices and receipt of weight‐loss advice among obese people with asthma. Research Methods and Procedures: We analyzed data from the 2000 Behavioral Risk Factor Surveillance System. Results: Among 13,953 participants with current asthma, 27.3% had a body mass index of ≥30 kg/m2. Overall, 48.1% of participants with asthma reported trying to lose weight (64.1% among overweight or obese participants and 72.9% among obese participants). Among participants with asthma who were trying to lose or maintain weight, 74.7% reported trying to reduce their energy and/or fat intake, and 57.8% reported using physical activity. Approximately 29.7% were using the recommended combination of energy and/or fat intake reduction and physical activity of ≥150 min/wk. During the 12 months before the interview, 16.2% of overweight and 44.9% of obese participants with asthma reported receiving advice to lose weight. Among obese participants receiving weight‐loss advice, 82.9% reported trying to lose weight compared to 63.8% of participants who did not receive such advice. Discussion: Health professionals can play an important role in educating their patients with asthma about the importance of weight control and assisting their overweight and obese patients in setting appropriate weight goals and helping them achieve those goals.     

Weight Loss Attempts and Attitudes toward Body Size,Eating, and Physical Activity in American Indian Children: Relationship to Weight Status and Gender

Objective: This study examined dieting, weight perceptions, and self‐efficacy to eat healthy foods and engage in physical activity and their relationships to weight status and gender among American Indian elementary schoolchildren. Research Methods and Procedures: Data for this study were collected as part of the baseline examination for the Pathways study. Participants were 1441 second‐ through third‐grade American Indian children in 41 schools representing seven tribes in Arizona, New Mexico, and South Dakota who filled out a questionnaire and had heights and weights taken. Results: Forty‐two percent of the children were overweight or obese. No differences were found between overweight/obese and normal weight children for healthy food intentions or self‐efficacy. Heavier children (especially those with body mass index > 95th percentile) were more likely to have tried to lose weight or were currently trying to lose weight. No gender differences were found. Normal weight children chose a slightly heavier body size as most healthy compared with overweight/obese children. Discussion: The results indicate that children are concerned about their weight and that weight modification efforts are common among overweight American Indian children. School, community, and family‐based programs are needed to help young people adopt lifelong healthful eating and physical activity practices.     

Comparison of Obese NIDDM and Nondiabetic Women: Short- and Long-Term Weight Loss

Previous research suggests that overweight patients with diabetes lose less weight than non diabetics. We compared the response of obese women with NIDDM to non diabetic controls, matched for age and weight, to a behavior weight loss program. Forty-three overweight women (20 NIDDM, 23 non diabetic) participated in the study. NIDDM and non diabetic subjects were treated together and received the same 16-week behavioral weight loss program. Dependent measures included weight, 3-day food records, physical activity, fasting plasma glucose, and questionnaires assessing eating behavior and depressive symptomatology. Weight loss of NIDDM and non diabetic subjects at posttreatment was comparable (-7.4 ± 5.3 kg vs. ?6.4 ± 3.8 kg, respectively). Changes in caloric intake, eating behavior, exercise and depressive symptomatology were also similar between the two groups. However, during the 1-year follow-up period, NIDDM subjects regained 5.4 ± 6.1 kg compared to 1.0 ± 6.7 kg for nondiabetics (p=.058). These data indicate that NIDDM subjects can lose as much weight as their nondiabetic peers during active treatment Once treatment terminated, however, NIDDM subjects demonstrated poor weight loss maintenance. Thus the added motivation that comes from having diabetes and seeing improvements in glycemic control with weight loss were not sufficient to improve long term weight loss in diabetic subjects. A continuous care model of weight control may be particularly necessary for overweight patients with type II diabetes.     

Obesity and Weight Control Practices in 2000 Among Veterans Using VA Facilities

Objective: To examine obesity prevalence and weight control practices among veterans who use Department of Veterans Affairs (VA) medical facilities (VA users). Research Methods and Procedures: Data from the 2000 Behavioral Risk Factor Surveillance System, a telephone survey of 184, 450 adults, were analyzed. Outcome measures included BMI, weight control practices (the intent to manage weight, and diet and physical activity patterns), and receipt of professional weight control advice. Results: Of VA users, 44% were overweight and 25% were obese. After controlling for demographic factors, VA users were somewhat less likely to be overweight (odds ratio, 0.86; 95% confidence interval, 0.74 to 1.00) but equally likely to be obese (odds ratio, 1.08; 95% confidence interval, 0.92 to 1.27), compared with non‐VA users. Among obese VA users, 75% reported trying to lose weight, and another 17% reported trying to maintain weight. Of these, only 40% decreased both calorie and fat intake. Only 27% of obese VA users who reported increasing exercise to lose weight followed recommendations for regular and sustained physical activity. Of obese VA users, 59% were inactive or irregularly active. Only 51% of obese VA users received professional advice to lose weight. Obese VA users were more likely than obese non‐VA users to report trying to lose weight, modifying diet to lose weight by decreasing both calories and fat intake, and receiving professional weight control advice. Discussion: Interventions for weight management programs in VA facilities need to take into account the high prevalence of overweight/obesity among VA users and should emphasize effective weight control practices.     

Physical activity compliance: differences between overweight/obese and normal-weight adults

Objectives: Comparisons of physical activity measured by accelerometers in overweight/obese adults and their normal‐weight counterparts are limited. Compliance with the 2002 Institute of Medicine (IOM) exercise recommendations for 60 minutes of moderate‐intensity exercise daily has not been reported. The purpose of this study was to compare physical activity, as measured by accelerometers, in overweight/obese adults vs. normal‐weight controls and to assess compliance with recommendations for physical activity by the IOM in 2002 and by the Centers for Disease Control and Prevention and American College of Sports Medicine in 1995 for 30 minutes of moderate‐intensity activity, preferably all days of the week. Research Methods and Procedures: Sixty‐two overweight/obese subjects, BMI ≥ 25, included 31 adults, 12 men and 19 women, 25 to 69 years old, and their normal‐weight controls, BMI 18.5 to 24.9, matched for gender, age, and height. Body composition was assessed using DXA. Physical activity was measured with Actigraph accelerometers (MTI, Fort Walton Beach, FL) worn by each participant for 7 consecutive days. Results: Accelerometry data indicated that overweight/obese adults recorded ～60 counts per minute less per day and spent 21 minutes less engaged in moderate or greater intensity activity than their normal‐weight counterparts. Although 71% to 94% of those studied met 1995 recommendations, only 13% of overweight/obese subjects and 26% of normal‐weight participants met 2002 exercise recommendations. Discussion: These results suggest that daily minutes spent in moderate‐intensity activity or greater are associated with weight status and that the 2002 IOM recommendations may be difficult to meet even for normal‐weight individuals.     

Perindopril treatment promote left ventricle remodeling in patients with heart failure screened positive for autoantibodies against angiotensin II type 1 receptor

Coronary artery disease (CAD) is accountable for more than 7 million deaths each year according to the World Health Organization (WHO). In a European population 80% of patients diagnosed with CAD are overweight and 31% are obese. Physical inactivity and overweight are major risk factors in CAD, thus central strategies in secondary prevention are increased physical activity and weight loss. In a randomized controlled trial 70 participants with stable CAD, age 45–75, body mass index 28–40 kg/m2 and no diabetes are randomized (1:1) to 12 weeks of intensive exercise or weight loss both succeeded by a 40-week follow-up. The exercise protocol consist of supervised aerobic interval training (AIT) at 85-90% of VO2peak 3 times weekly for 12 weeks followed by supervised AIT twice weekly for 40 weeks. In the weight loss arm dieticians instruct the participants in a low energy diet (800–1000 kcal/day) for 12 weeks, followed by 40 weeks of weight maintenance combined with supervised AIT twice weekly. The primary endpoint of the study is change in coronary flow reserve after the first 12 weeks’ intervention. Secondary endpoints include cardiovascular, metabolic, inflammatory and anthropometric measures. The study will compare the short and long-term effects of a protocol consisting of AIT alone or a rapid weight loss followed by AIT. Additionally, it will provide new insight in mechanisms behind the benefits of exercise and weight loss. We wish to contribute to the creation of effective secondary prevention and sustainable rehabilitation strategies in the large population of overweight and obese patients diagnosed with CAD. ClinicalTrials.gov: NCT01724567     

Weight loss and exercise training effect on oxygen uptake and heart rate response to locomotion

Effects of resistance and aerobic training on the ease of physical activity during and after weight loss are unknown. The purpose of the study was to determine what effect weight loss combined with either aerobic or resistance training has on the ease of locomotion (net V[Combining Dot Above]O2 and heart rate). It is hypothesized that exercise training will result in an increased ease, lowers heart rate during locomotion. Seventy-three overweight premenopausal women were assigned to diet and aerobic training, diet and resistance training, or diet only. Subjects were evaluated while overweight, after diet-induced weight loss (average, 12.5 kg loss), and 1 year after weight loss (5.5 kg regain). Submaximal walking, grade walking, stair climbing, and bike oxygen uptake and heart rate were measured at all time points. Weight loss diet was 800 kcal per day. Exercisers trained 3 times per week during weight loss and 2 times per week during 1-year follow-up. Resistance training increased strength, and aerobic training increased maximum oxygen uptake. Net submaximal oxygen uptake was not affected by weight loss or exercise training. However, heart rate during walking, stair climbing, and bicycling was reduced after weight loss. No significant differences in reduction in heart rate were observed among the 3 treatment groups for locomotion after weight loss. However, during 1-year follow-up, exercise training resulted in maintenance of lower submaximal heart rate, whereas nonexercisers increased heart rate during locomotion. Results suggest that moderately intense exercise is helpful in improving the ease of movement after weight loss. Exercise training may be helpful in increasing the participation in free-living physical activity.     

Health-related quality of life and weight loss among overweight and obese U.S. adults, 2001 to 2002

Objective: To examine the prevalence and association of health‐related quality of life (HRQOL) with trying to lose weight and with weight loss practices (eating fewer calories, physical activity, and both) among overweight and obese U.S. adults ≥ 20 years of age. Research Methods and Procedures: This study used data from the 2001 to 2002 National Health and Nutrition Examination Survey, a continuous annual survey of the civilian non‐institutionalized U.S. population. This analysis included those ≥ 20 years of age with BMI ≥ 25 (n = 2578) who responded to four standard HRQOL measures that assessed general health status and recent physical health, mental health, and activity limitation. Results: Among obese men, but not women, there were significant increasing linear trends in the adjusted prevalence of trying to lose weight as physically unhealthy and activity limitation days increased. Regardless of BMI or HRQOL, reducing calories was a common weight loss practice (66% to 86%). Except for recent activity limitation, respondents with BMI ≥ 35 did not generally differ by HRQOL level in the attainment of recommended physical activity either alone or in combination with reduced calories, whereas those in the BMI 25 to 34.9 groups often differed significantly by HRQOL level. Specifically, increased unhealthy or activity limitation days were associated with reduced prevalence of attained physical activity. Discussion: Our findings indicate an association between trying to lose weight and a greater number of unhealthy days reported by obese men, suggesting that these men may be influenced by traditional clinical weight‐loss counseling that is prompted by weight and comorbidity, whereas women had a high prevalence of trying to lose weight irrespective of weight and HRQOL. Assessment of HRQOL, especially measures that evaluate physical domains, could provide subjective information to assist with weight counseling.     

Geographic Variation in the Prevalence of Obesity,Diabetes, and Obesity‐Related Behaviors**

Objective: To examine the variation in the prevalences of obesity and type 2 diabetes in weight loss counseling by health providers and in other potential obesity‐related determinants in 100 metropolitan statistical areas in the United States. Research Methods and Procedures: We performed a cross‐sectional study using data from the 2000 Behavioral Risk Factor Surveillance System, the largest telephone survey of health behaviors in the United States, of age‐adjusted prevalence of obesity, type 2 diabetes, intake of ≥five servings of fruits and vegetables per day, participation in 150 minutes of leisure‐time physical activity per week, receipt of weight management advice, and reports of trying to lose or maintain weight among men and women more than 18 years old. Results: The age‐adjusted prevalence of obesity ranged from 13.1% to 30.0% and that of type 2 diabetes from 3.3% to 9.2%. Among participants who had visited a physician for a routine checkup in the previous 12 months, 13.1% to 27.1% of all participants recalled receiving advice from a health professional about their weight, and 11.7% to 34.6% of overweight or obese participants recalled receiving advice to maintain or lose weight. Discussion: Significant differences in the prevalence of obesity and self‐reported type 2 diabetes and in medical practice patterns regarding weight management advice exist among metropolitan statistical areas. These results suggest important opportunities to investigate reasons for these variations that could potentially be used to mitigate the current epidemic of obesity and to identify areas where obesity and diabetes prevention efforts may need to be targeted.     

Prevalence of Overweight and Obesity and Weight Loss Practice among Beijing Adults, 2011

Objective

This study aims to determine the up-to-date prevalence of overweight and obesity, the distributions of body weight perception and weight loss practice in Beijing adults.

Methods

A cross-sectional study was conducted in 2011. A total of 2563 men and 4088 women aged 18–79 years from the general population were included. Data were obtained from questionnaire and physical examination.

Results

The prevalence of overweight (BMI 24–27.9 kg/m²) and obesity (BMI≥28 kg/m²) was 42.1% and 20.3% in men and 35.6% and 17.1% in women, respectively. Age was inversely associated with overweight in both sexes, and obesity in women. Education level was negatively associated with overweight and obesity in women but not in men. Only 49.1% men and 58.3% women had a correct perception of their body weight. Underestimation of body weight was more common than overestimation, especially in men, the older people, and those with low education level. The percentage of taking action to lose weight was inversely associated with men and old age, and positively associated with higher education level, higher BMI, and self-perception as “fat” (OR = 3.78 in men, OR = 2.91 in women). Only 26.1% of overweight/obese individuals took action to lose weight. The top two weight loss practices were to reduce the amount of food intake and exercise.

Conclusion

Overweight and obesity were highly prevalent with high incorrect body weight perceptions in the general adult population in Beijing. Weight loss practice was poor in overweight and obese individuals. Actions at multiple levels are needed to slow or control this overweight and obesity epidemic.     

RCT of a High‐protein Diet on Hunger Motivation and Weight‐loss in Obese Children: An Extension and Replication

This study aimed to evaluate the weight loss and hunger motivation effects of an energy‐restricted high‐protein (HP) diet in overweight and obese children. In total, 95 overweight and obese children attended an 8‐week (maximum) program of physical activity, reduced‐energy intake, and behavior change education. Children were randomly assigned to one of two isoenergetic diets (standard (SP): 15% protein; HP: 25% protein), based on individually estimated energy requirements. Anthropometry and body composition were assessed at the start and end of the program and appetite and mood ratings completed on the first 3 consecutive weekdays of each week children attended camp. The HP diet had no greater effect on weight loss, body composition, or changes in appetite or mood when compared to the SP diet. Overall, campers lost 5.2 ± 3.0 kg in body weight and reduced their BMI standard deviation score (sds) by 0.25. Ratings of desire to eat increased significantly over the duration of the intervention, irrespective of diet. This is the third time we have reported an increase in hunger motivation in weight‐loss campers and replicates our previous failure to block this with a higher protein diet. Further work is warranted into the management of hunger motivation as a result of negative energy balance.     

Diet and Physical Activity Behaviors among Americans Trying to Lose Weight: 2000 Behavioral Risk Factor Surveillance System

Objective: To examine the prevalence and correlates of trying to lose weight among U.S. adults, describe weight loss strategies, and assess attainment of recommendations for weight control (eating fewer calories and physical activity). Research Methods and Procedures: This study used the Behavioral Risk Factor Surveillance System, a state‐based telephone survey of adults ≥18 years of age (N = 184, 450) conducted in the 50 states, the District of Columbia, and Puerto Rico in 2000. Results: The prevalence of trying to lose weight was 46% (women) and 33% (men). Women reported trying to lose weight at a lower BMI than did men; 60% of overweight women were trying to lose weight, but men did not reach this level until they were obese. Adults who had a routine physician checkup in the previous year and reported medical advice to lose weight vs. checkup and no medical advice to lose weight had a higher prevalence of trying to lose weight (81% women and 77% men vs. 41% women and 28% men, respectively). The odds of trying to lose weight increased as years of education increased. Among respondents who were trying to lose weight, ～19% of women and 22% of men reported using fewer calories and ≥150 min/wk leisure‐time physical activity. Discussion: A higher percentage of women than men were trying to lose weight; both sexes used similar weight loss strategies. Education and medical advice to lose weight were strongly associated with trying to lose weight. Most persons trying to lose weight were not using minimum recommended weight loss strategies.     

Adolescent exergame play for weight loss and psychosocial improvement: A controlled physical activity intervention

Overweight and obese youth, who face increased risk of medical complications including heart disease and type II diabetes, can benefit from sustainable physical activity interventions that result in weight loss.

Objective:

This study examined whether a 20‐week exergame (i.e., videogame that requires gross motor activity) intervention can produce weight loss and improve psychosocial outcomes for 54 overweight and obese African‐American adolescents.

Design and Methods:

Participants were recruited from a public high school and randomly assigned to competitive exergame, cooperative exergame, or control conditions. All exergame participants were encouraged to play the Nintendo Wii Active game for 30‐60 min per school day in a lunch‐time or after‐school program. Cooperative exergame participants worked with a peer to expend calories and earn points together, whereas competitive exergame participants competed against a peer. Control participants continued regular daily activities. Outcome measures included changes in weight, peer support, self‐efficacy, and self‐esteem, measured at baseline, and at ～10 and 20 weeks.

Results:

Growth curve analysis revealed that cooperative exergame players lost significantly more weight (mean = 1.65 kg; s.d. = 4.52) than the control group, which did not lose weight. The competitive exergame players did not differ significantly from the other conditions. Cooperative exergame players also significantly increased in self‐efficacy compared to the control group, and both exergame conditions significantly increased in peer support more than the control group.

Conclusion:

Exergames, especially played cooperatively, can be an effective technological tool for weight loss among youth.     

Identification and correlates of weight loss in adolescents in a national sample

Objective: Little is known about behaviors associated with successful weight loss during adolescence. The first objective of the current study was to identify meaningful weight loss, weight maintenance, and weight gain in male and female adolescents. The second objective of this study was to apply these methods to U.S. adolescents from the National Health and Nutrition Survey 1999 to 2002 data and to identify factors associated with these weight change outcomes. Research Methods and Procedures: The current analyses include 1726 (female, 836; male, 890) 16‐ to 18‐year‐old adolescents who completed the questionnaire components and interview for either the 1999–2000 or the 2001–2002 National Health and Nutrition Survey study. Dietary intake, physical activity, and dieting attitudes were compared across the weight loss (L), maintain (M), and gain (G) groups in the entire sample and in a subset of adolescents who are overweight and at‐risk‐for‐overweight (≥85th percentile). Results: The tested method for identifying weight L, M, and G groups has both theoretical and statistical validity and, when applied to the sample, showed the expected direction of changes in weight. Results suggest that more overall physical activity, more vigorous exercise, and less sedentary activity are associated with being in the L group in both the full sample and the overweight and at‐risk‐for‐overweight sample. In addition, fewer teens in the L groups endorsed efforts at trying to lose weight, compared with the M and G groups. Discussion: This study provides a method to determine successful adolescent weight loss for researchers and provides useful concrete information about successful weight loss for clinicians and others who work with adolescents.     

Aerobic exercise alone results in clinically significant weight loss for men and women: Midwest exercise trial 2

Exercise is recommended by public health agencies for weight management; however, the role of exercise is generally considered secondary to energy restriction. Few studies exist that have verified completion of exercise, measured the energy expenditure of exercise, and prescribed exercise with equivalent energy expenditure across individuals and genders.

Objective:

The objective of this study was to evaluate aerobic exercise, without energy restriction, on weight loss in sedentary overweight and obese men and women.

Design and Methods:

This investigation was a randomized, controlled, efficacy trial in 141 overweight and obese participants (body mass index, 31.0 ± 4.6 kg/m²; age 22.6 ± 3.9 years). Participants were randomized (2:2:1 ratio) to exercise at either 400 kcal/session or 600 kcal/session or to a nonexercise control. Exercise was supervised, 5 days/week, for 10 months. All participants were instructed to maintain usual ad libitum diets. Because of the efficacy design, completion of ≥90% of exercise sessions was an a priori definition of per protocol, and these participants were included in the analysis.

Results:

Weight loss from baseline to 10 months for the 400 and 600 kcal/session groups was 3.9 ± 4.9 kg (4.3%) and 5.2 ± 5.6 kg (5.7%), respectively, compared with weight gain for controls of 0.5 ± 3.5 kg (0.5%) (P < 0.05). Differences for weight loss from baseline to 10 months between the exercise groups and differences between men and women within groups were not statistically significant.

Conclusions:

Supervised exercise, with equivalent energy expenditure, results in clinically significant weight loss with no significant difference between men and women.     

Ethnic and sex variations in overweight self-perception: relationship to sedentariness

Objective: With increasing frequency, health promotion messages advocating physical activity are claiming weight loss as a benefit. However, messages promoting physical activity as a weight loss strategy may have limited effectiveness and cross‐cultural relevance. We recently found self‐perceived overweight to be a more robust correlate of sedentary behavior than BMI in Los Angeles County adults. In this study, we examined ethnic and sex differences in overweight self‐perception and their association with sedentariness in this sample. Research Methods and Procedures: We conducted bivariate and multivariate analyses of cross‐sectional survey data from a representative sample of Los Angeles County adults. Results: Women were more likely to perceive themselves to be overweight than men overall (73.2% of overweight/non‐obese and 24.1% of average weight women vs. 44.5% of overweight/non‐obese and 5.6% of average weight men) and within each ethnic group. African‐Americans were least likely (41.3% of overweight/non‐obese African‐Americans self‐identified as overweight) and whites were most likely to consider themselves overweight (60.6% of overweight/non‐obese whites self‐identified as overweight). Overweight (vs. average weight) self‐perception was correlated with sedentariness among average weight adults (45.3% vs. 33.0%, p < 0.001), overweight adults (43.4% vs. 33.6%, p < 0.001), men (average and overweight: 38.4% vs. 27.8%, p < 0.001), overweight whites (41.9% vs. 29.7%, p = 0.0012), and African‐Americans and Latinos (41.6% vs. 33.9%, p = 0.005). Discussion: These data suggest that our society's emphasis on weight loss rather than lifestyle change may inadvertently discourage physical activity adoption/maintenance among non‐obese individuals. However, further research is needed, particularly from prospective cohort and intervention studies, to elucidate the relationship between overweight self‐perception and healthy lifestyle change.     

Predicting treatment initiation in a family-based adolescent overweight and obesity intervention

Little is known about factors associated with treatment initiation in overweight and obese adolescents. This study investigated parent-reported adolescent demographic, adolescent health, and parent motivation factors associated with initiation of a family-based adolescent overweight and obesity intervention. A telephone survey was completed by 349 parents calling to register their interest in participating in a cognitive behavioral lifestyle intervention for adolescent overweight and obesity. A total of 172 families (49.3%) returned their consent form to initiate treatment. A binomial logistic regression, with predictors entered in three blocks: (i) adolescent demographic (adolescent age, gender, adolescent BMI-for-age z-score, parent BMI); (ii) adolescent health (perceived adolescent physical and mental health, presence of an adolescent physical health problem or mental health problem, medication intake); and (iii) parent motivation (perceived adolescent weight category, concern about adolescent weight, importance of adolescent weight, confidence in adolescent capacity to change weight, priority of adolescent weight loss, discrepancy between adolescent current and ideal weight, previous weight loss attempts), was significant (χ2 (16) = 35.19, P = 0.004) accounting for 12.4-16.5% (95% confidence interval) of treatment initiation variance. Parent-reported adolescent physical health problem, parent perception of adolescent weight category, parent priority of adolescent weight loss, and parent perception of discrepancy between adolescent current and ideal weight were significant in the model. These findings indicate that data collected at intake are associated with treatment initiation and highlight the role of assessing and enhancing treatment motivation from initial contact.     

Maximal heart rate prediction in adults that are overweight or obese

An accurate predictor of maximal heart rate (MHR) is necessary to prescribe safe and effective exercise in those considered overweight and obese when actual measurement of MHR is unavailable or contraindicated. To date, accuracy of MHR prediction equations in individuals that are overweight or obese has not been well established. The purpose of this study was to examine the accuracy of 3 equations for predicting MHR in adults that are overweight or obese. One hundred seventy-three sedentary adults that were overweight or obese enrolled in weight-loss study and performed a VO?peak treadmill test before the start of the weight loss treatment. A total of 132 of the 173 participants met conditions for achieving maximal exercise testing criteria and were included in this study. Maximal heart rate values determined from VO?peak treadmill tests were compared across gender, age, and weight status with the following prediction equations: (a) 220 - age, (b) 208 - 0.7 × age, and (c) 200 - 0.48 × age. Among 20- to 40-year-old participants, actual MHR averaged 180 ± 9 b·min?1 and was overestimated (p < 0.001) at 186 ± 5 b·min?1 with the 220 - age equation. Weight status did not affect predictive accuracy of any of the 3 equations. For all participants, the equation, 200-0.48 × age estimated MHR to be 178 ± 4 b·min?1, which was greater than the actual value (175 ± 12, p = 0.005). Prediction equations showed close agreement to actual MHR, with 208 - 0.7 × age being the most accurate.     

Separate and combined effects of exercise training and weight loss on exercise efficiency and substrate oxidation

Perturbations in body weight have been shown to affect energy expenditure and efficiency during physical activity. The separate effects of weight loss and exercise training on exercise efficiency or the proportion of energy derived from fat oxidation during physical activity, however, are not known. The purpose of this study was to determine the separate and combined effects of exercise training and weight loss on metabolic efficiency, economy (EC), and fat oxidation during steady-state moderate submaximal exercise. Sixty-four sedentary older (67 +/- 0.5 yr) overweight to obese (30.7 +/- 0.4 kg/m(2)) volunteers completed 4 mo of either diet-induced weight loss (WL; n = 11), exercise training (EX; n = 36), or the combination of both interventions (WLEX; n = 17). Energy expenditure, gross efficiency (GE), EC, and proportion of energy expended from fat (EF) were determined during a 1-h submaximal (50% of peak aerobic capacity) cycle ergometry exercise before the intervention and at the same absolute work rate after the intervention. We found that EX increased GE by 4.7 +/- 2.2%. EC was similarly increased by 4.2 +/- 2.1% by EX. The addition of concomitant WL to EX (WLEX) resulted in greater increases in GE (9.0 +/- 3.3%) compared with WL alone but not compared with EX alone. These effects remained after adjusting for changes in lean body mass. The proportion of energy derived from fat during the bout of moderate exercise increased with EX and WLEX but not with WL. From these findings, we conclude that exercise training, either alone or in combination with weight loss, increases both exercise efficiency and the utilization of fat during moderate physical activity in previously sedentary, obese older adults. Weight loss alone, however, significantly improves neither efficiency nor utilization of fat during exercise.