Evidence-Based, High-Intensity Exercise and Physical Activity for Compressing Morbidity in Older Adults: A Narrative Review.

Recent research in exercise science has important applications for middle-aged and older adults and points to how the programming of individual and multicomponent interventions including theory-based health behavior change strategies may be improved to compress morbidity by delaying or reducing the disabling process. High-intensity interval training and sprint interval training until recently were seen as only applicable to athletes. But recent lab-based research has adapted these interventions for even older adults and demonstrated their safety with beneficial outcomes on cardiometabolic risk factors comparable to or surpassing the usual lower- to moderate-intensity endurance training, and their potential translatability by showing the efficacy of much lower duration and frequency of training, even by systematic stair climbing. Moreover, people report positive affect while engaged in such training. For a century, resistance training was conceived as weightlifting with heavy weights required. Recent research has shown that using a higher degree of effort with lighter to moderate resistance in simple, time efficient protocols result in gains in strength and muscle mass similar to heavy resistance, as well as improvement of cardiometabolic risk factors, strength, body composition, and cognitive, affective, and functional abilities. More effort-based resistance training with moderate resistance may make resistance training more appealing and accessible to older adults. A key potential translational finding is that with correct technique and a high degree of effort, training with inexpensive, portable elastic bands, useable virtually anywhere, can provide appreciable benefits. More emphasis should be placed on long-term, translational interventions, resources, and programs that integrate interval and resistance trainings. This work may improve public health programs for middle-aged and older adults and reflects an emerging evidence base.

Resistance training is associated with spontaneous changes in aerobic physical activity but not overall diet quality in adults with prediabetes.

BACKGROUND: Aerobic exercise interventions have been shown to result in alterations to dietary intake and non-exercise physical activity (PA). To date, the ability for resistance training (RT) to influence other health-related behaviors has not been examined. This study aimed to determine if initiation and maintenance of RT is associated with spontaneous changes in dietary quality and non-RT PA in adults with prediabetes. METHODS: Overweight/obese adults (n=170, BMI=32.9±3.8kg·m2, age=59.5±5.5years, 73% female) with prediabetes were enrolled in the 15-month Resist Diabetes trial. Participants completed a supervised 3-month RT initiation phase followed by a 6-month maintenance phase and a 6-month no-contact phase. Participants were not encouraged to change eating or non-RT PA behaviors. At baseline, and months 3, 9, and 15, three 24-hour diet recalls were collected to evaluate dietary intake and quality, the Aerobics Institute Longitudinal Study Questionnaire was completed to evaluate non-RT PA, and body mass, body composition (DXA), and muscular strength were measured. At months 3, 9, and 15 social cognitive theory (SCT) constructs were assessed with a RT Health Beliefs Questionnaire. Mixed effects models were used to assess changes in dietary intake and non-RT PA over the 15-month study period. RESULTS: Energy and carbohydrate intake decreased with RT initiation and maintenance phases (baseline to month 9: ß=-87.9, p=0.015 and ß=-16.3, p<0.001, respectively). No change in overall dietary quality (Healthy Eating Index [HEI]-2010 score: ß=-0.13, p=0.722) occurred, but alterations in HEI-2010 sub-scores were detected. Maintenance of RT was accompanied by an increase in MET-min/week of total non-RT PA (month 3 to month 9: ß=146.2, p=0.01), which was predicted by increased self-regulation and decreased negative outcome expectancies for RT (ß=83.7, p=0.014 and ß=-70.0, p=0.038, respectively). CONCLUSIONS: Initiation and maintenance of RT may be a gateway behavior leading to improvements in other health-related behaviors. These results provide rationale for single-component lifestyle interventions as an alternative to multi-component interventions, when resources are limited.

Resist diabetes: A randomized clinical trial for resistance training maintenance in adults with prediabetes.

OBJECTIVE: To determine whether a social cognitive theory (SCT)-based intervention improves resistance training (RT) maintenance and strength, and reduces prediabetes prevalence. RESEARCH DESIGN AND METHODS: Sedentary, overweight/obese (BMI: 25-39.9 kg/m2) adults aged 50-69 (N = 170) with prediabetes participated in the 15-month trial. Participants completed a supervised 3-month RT (2×/wk) phase and were randomly assigned (N = 159) to one of two 6-month maintenance conditions: SCT or standard care. Participants continued RT at a self-selected facility. The final 6-month period involved no contact. Assessments occurred at baseline and months 3, 9, and 15. The SCT faded-contact intervention consisted of nine tailored transition (i.e., supervised training to training alone) and nine follow-up sessions. Standard care involved six generic follow-up sessions. Primary outcomes were prevalence of normoglycemia and muscular strength. RESULTS: The retention rate was 76%. Four serious adverse events were reported. After 3 months of RT, 34% of participants were no longer prediabetic. This prevalence of normoglycemia was maintained through month 15 (30%), with no group difference. There was an 18% increase in the odds of being normoglycemic for each % increase in fat-free mass. Increases in muscular strength were evident at month 3 and maintained through month 15 (P<0.001), which represented improvements of 21% and 14% for chest and leg press, respectively. Results did not demonstrate a greater reduction in prediabetes prevalence in the SCT condition. CONCLUSIONS: Resistance training is an effective, maintainable strategy for reducing prediabetes prevalence and increasing muscular strength. Future research which promotes RT initiation and maintenance in clinical and community settings is warranted. TRIAL REGISTRATION: ClinicalTrials.gov NCT01112709.

Psychosocial mediators of a theory-based resistance training maintenance intervention for prediabetic adults.

OBJECTIVE: Examine psychosocial mediators of the effects of high vs. low-dose resistance training (RT) maintenance interventions among older (ages 50-69), overweight and pre-diabetic adults. DESIGN: Participants (N = 123) completed a three-month supervised RT initiation phase and were subsequently randomised (time 1) to high or low-dose six-month unsupervised RT maintenance interventions (time 2), followed by a six-month no-contact phase (time 3). MAIN OUTCOME MEASURES: Online measures of putative mediators and RT behaviour. RESULTS: RT intervention condition (high vs. low dose) had significant effects on change from time 1 to time 2 in behavioural expectation, self-regulation and perceived satisfaction (f(2) = .04-.08), but not outcome expectancies, RT strategies or behavioural intentions (f(2) ≤ .02). Change in each of the putative mediators, except for outcome expectancies (f(2) ≤ .02), had significant effects on RT behaviour at times 2 (f(2) = .12-.27) and 3 (f(2) = .23-.40). In a multiple mediation model, behavioural expectation (f(2) = .11) and self-regulation (f(2) = .06) mediated the effects of RT intervention condition on time 2 RT behaviour, whereas perceived satisfaction did not (f(2) = .01). Self-regulation was a significant mediator of intervention effects on time 3 RT behaviour (f(2) = .11), but behavioural expectation and perceived satisfaction were not (f(2) = .04). CONCLUSIONS: Findings suggest that behavioural expectation and self-regulation are appropriate targets for RT maintenance interventions among at-risk older adults.

Prediabetes Phenotype Influences Improvements in Glucose Homeostasis with Resistance Training.

PURPOSE: To determine if prediabetes phenotype influences improvements in glucose homeostasis with resistance training (RT). METHODS: Older, overweight individuals with prediabetes (n = 159; aged 60±5 yrs; BMI 33±4 kg/m2) completed a supervised RT program twice per week for 12 weeks. Body weight and composition, strength, fasting plasma glucose, 2-hr oral glucose tolerance, and Matsuda-Defronza estimated insulin sensitivity index (ISI) were assessed before and after the intervention. Participants were categorized according to their baseline prediabetes phenotype as impaired fasting glucose only (IFG) (n = 73), impaired glucose tolerance only (IGT) (n = 21), or combined IFG and IGT (IFG/IGT) (n = 65). RESULTS: Chest press and leg press strength increased 27% and 18%, respectively, following the 12-week RT program (both p<0.05). Waist circumference (-1.0%; pre 109.3±10.3 cm, post 108.2±10.6 cm) and body fat (-0.6%; pre 43.7±6.8%, post 43.1±6.8%) declined, and lean body mass (+1.3%; pre 52.0±10.4 kg, post 52.7±10.7 kg) increased following the intervention. Fasting glucose concentrations did not change (p>0.05) following the intervention. However, 2-hr oral glucose tolerance improved in those with IGT (pre 8.94±0.72 mmol/l, post 7.83±1.11 mmol/l, p<0.05) and IFG/IGT (pre 9.66±1.11mmol/l, post 8.60±2.00 mmol/l) but not in those with IFG (pre 6.27±1.28mmol/l, post 6.33± 1.55 mmol/l). There were no significant changes in ISI or glucose area under the curve following the RT program. CONCLUSIONS: RT without dietary intervention improves 2-hr oral glucose tolerance in individuals with prediabetes. However, the improvements in glucose homeostasis with RT appear limited to those with IGT or combined IFG and IGT. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01112709.

Theory-based approach for maintaining resistance training in older adults with prediabetes: adherence, barriers, self-regulation strategies, treatment fidelity, costs.

Effectively preventing and treating chronic diseases through health behavior changes often require intensive theory- and evidence-based intervention including long-term maintenance components. We assessed the efficacy of theory-based maintenance approaches varying by dose for persistently performing resistance training (RT) with the hypothesis that a higher-dose social cognitive theory (SCT) approach would produce greater RT adherence than lower-dose Standard. The Resist-Diabetes study first established 2×/week resistance training (RT) in a 3-month supervised intervention in older (50-69 years, N = 170), overweight to obese (BMI 25-39.9 kg/m(2)) previously inactive adults who fit prediabetes criteria (fasting glucose concentration = 95-125 mg/dl; oral glucose tolerance test 2-h glucose concentration = 140-199 mg/dl or both). After the supervised phase, participants (N = 159) were then randomly assigned to one of two conditions for transition (3 weeks) and then RT alone in community settings for extended contact, maintenance (6 months), and then no contact (6 months). SCT featured continued tailored, interactive personal, and web-based check-ups focused on RT, self-regulation, and a barrier/strategies approach. Standard involved low-dose, generic personal, and web-based check-ups within the same theoretical approach. SCT and Standard both resulted in similar RT, 2×/week adherence during maintenance (74.4 %) and no-contact phases (53.1 %). Cost analysis indicated the Standard intervention for transition and maintenance was inexpensive ($160). Standard can be translated into practice with the potential for continuous contact and persistence in RT beyond the typical program maintenance phase.

Questionnaires for outcome expectancy, self-regulation, and behavioral expectation for resistance training among young-old adults: development and preliminary validity.

The purpose of the present research was to develop questionnaires to assess outcome expectancy for resistance training (RT), behavioral expectation in the context of perceived barriers to RT, and self-regulation strategies for RT among young-old adults (50-69 years). Measurement development included (a) item generation through elicitation interviews (N = 14) and open-ended questionnaires (N = 56), (b) expert feedback on a preliminary draft of the questionnaires (N = 4), and (c) a quantitative longitudinal study for item-reduction and psychometric analyses (N = 94). Elicitation procedures, expert feedback, and item reduction yielded four questionnaires with a total of 33 items. Positive outcome expectancy (α = .809), negative outcome expectancy (α = .729), behavioral expectation (α = .925), and self-regulation (α = .761) had-with one exception-moderate bivariate associations with two different indicators of self-reported RT behavior at one-month follow-up (r = .298 to .506). The present research provides preliminary support for newly developed questionnaires to facilitate understanding of the psychosocial determinants of RT among young-old adults.

Using response variation to develop more effective, personalized behavioral medicine?: evidence from the Resist Diabetes study.

Health behavior interventions have achieved some notable outcomes through generally higher dose interventions with intensive initial phases and long-term, faded contact maintenance phases with attention to mean changes and adherence rates. Interventions may be improved by shifting attention to the very large response variation that is typical for such protocols as exercise with non-, low, moderate, and high responders and even those who show adverse responses. Data from the Resist Diabetes study, which included adults (N = 159, ages 50-69 years) with prediabetes who were overweight or obese (BMI 25-39.9 kg/m(2)) and previously inactive, are presented. The data show a typical pattern of wide variation for changes on a 2-h oral glucose tolerance test (OGTT), defined by blood glucose concentration measured after 2 h following ingestion of 75 g of glucose, lean body mass, fat mass, strength, and blood pressure to the same resistance training protocol within a highly supervised phase and where adherence was high. A personalized behavioral medicine approach could focus on such individual patterns of response variation to tailor and alter additional intervention components, the staging of maintenance interventions, and then determining how to most effectively, and systematically, translate this adaptive intervention approach into practice to potentially achieve more optimal clinical outcomes.

Dietary intake modification in response to a participation in a resistance training program for sedentary older adults with prediabetes: findings from the Resist Diabetes study.

Engagement in one type of health behavior change may exert a "spillover" effect resulting in other behavior changes. Few studies have examined dietary intake following prolonged training, and none have evaluated spontaneous dietary changes beyond alterations in energy or macronutrient intake following initiation of strength/resistance training (RT). The purpose of this observational investigation was to determine if spontaneous dietary intake modifications occur in response to initiation of an RT program, among older adults. Previously sedentary adults with prediabetes (n=134, age=59±1 years) were enrolled in a supervised 12-week RT program. Participants were not given dietary advice or encouraged to change eating behaviors. Three non-consecutive 24-hour dietary recalls were collected at baseline and after 12 weeks of RT. Reductions in intake of energy (1914±40 kcal vs. 1834±427 kcal, p=0.010), carbohydrate (211.6±4.9 g vs. 201.7±5.2 g, p=0.015), total sugar (87.4±2.7 g vs. 81.5±3.1 g, p=0.030), glycemic load (113.4±3.0 vs. 108.1±3.2, p=0.031), fruits and vegetables (4.6±0.2 servings vs. 4.1±0.2 servings, p=0.018), and sweets and desserts (1.1±0.07 servings vs. 0.89±0.07 servings, p=0.023) were detected over time. No changes in other dietary intake variables were observed. Mode of exercise and disease state may be important factors in determining whether dietary modifications occur with exercise initiation, among previously sedentary adults. Successful initiation of RT may represent an opportunity for health care professionals to promote beneficial changes in dietary habits, among older adults with prediabetes.

Developing a new treatment paradigm for disease prevention and healthy aging.

An increasingly prevalent pattern of risk factors has emerged in middle-aged and older adults that includes the presence of type 2 diabetes or prediabetes, overweight or obese weight status with central obesity and very high body fat, low cardiorespiratory fitness (CRF), low strength, and a low lean-body-mass-to-body-fat ratio. Traditionally, these problems have been approached with a low-fat and low-calorie diet and with lower to moderate intensity activity such as walking. While the treatment has some clear benefits, this approach may no longer be optimal because it does not reflect more recent findings from nutrition and exercise sciences. Specifically, these fields have gained a greater understanding of the metabolic and functional importance of focusing on reducing body fat and central obesity while maintaining or even increasing lean body mass, a quality weight loss, and how to efficiently and effectively increase CRF and strength. Evidence is presented for shifting the treatment paradigm for disease prevention and healthy aging to include the DASH nutrition pattern but with additional protein, higher intensity, brief aerobic training, effort-based, brief resistance training, and structured physical activity. Recent interventions based on social cognitive theory for initiating and then maintaining health behavior changes show the feasibility and efficacy of the approach we are advocating especially within a multiple health behavior change format and the potential for translating the new treatment paradigm into practice.

DASH to wellness: emphasizing self-regulation through e-health in adults with prehypertension.

OBJECTIVE: High prevalence rates of prehypertension require nonpharmaceutical lifestyle interventions. The objective of this study was to assess the feasibility and initial efficacy of a primarily electronically delivered intervention for prehypertension. METHODS: Twenty-three adults with prehypertension (M age of 54.3; systolic blood pressure [BP], 126.3 mmHg; weight, 87.8 kg; body mass index, 31.5; 6514 steps/day) were randomized to DASH 2 wellness only standard of care or to DASH 2 wellness plus. Both groups received instruction on the DASH eating plan, instructions to increase steps per day and use of a weight scale and pedometer, and information about social-cognitive theory-based self-regulation strategies. D2W plus also involved home blood pressure monitoring and monitoring steps per day, nutrition, and body weight. Through weekly newsletters, participants engaged in electronic reporting and goal setting and received feedback on progress. RESULTS: D2W plus showed a larger increase in daily steps (M = 2,900) than D2W only (M = 636); a larger decrease in systolic BP (mmHg), M = 15.1 versus M = 4.6, and a larger decrease in weight (in kg), M = 4.8 versus M = 1.5. CONCLUSIONS: Concentrating efforts not only toward adoption and initiation of innovative risk-reduction strategies but also toward the provision for long-term maintenance of a healthy lifestyle once initial changes have been accomplished is paramount. The D2W plus program could be adapted for such use in health care and other settings for treating prehypertension.

The resist diabetes trial: Rationale, design, and methods of a hybrid efficacy/effectiveness intervention trial for resistance training maintenance to improve glucose homeostasis in older prediabetic adults.

Advancing age is associated with reduced levels of physical activity, increased body weight and fat, decreased lean body mass, and a high prevalence of type 2 diabetes (T2D). Resistance training (RT) increases muscle strength and lean body mass, and reduces risk of T2D among older adults. The Resist Diabetes trial will determine if a social cognitive theory (SCT)-based intervention improves RT maintenance in older, prediabetic adults, using a hybrid efficacy/effectiveness approach. Sedentary, overweight/obese (BMI: 25-39.9 kg/m(2)) adults aged 50-69 (N = 170) with prediabetes (impaired fasting glucose and/or impaired glucose tolerance) completed a supervised 3-month RT (2×/wk) initiation phase and were then randomly assigned (N = 159; 94% retention) to one of two 6-month maintenance conditions: SCT or standard care. The SCT intervention consisted of faded contacts compared to standard care. Participants continue RT at an approved, self-selected community facility during maintenance. A subsequent 6-month period involves no contact for both conditions. Assessments occur at baseline and months 3 (post-initiation), 9 (post-intervention), and 15 (six months after no contact). Primary outcomes are prediabetes indices (i.e., impaired fasting and 2-hour glucose concentration) and strength. Secondary measures include insulin sensitivity, beta-cell responsiveness, and disposition index (oral glucose and C-peptide minimal model); adherence; body composition; and SCT measures. Resist Diabetes is the first trial to examine the effectiveness of a high fidelity SCT-based intervention for maintaining RT in older adults with prediabetes to improve glucose homeostasis. Successful application of SCT constructs for RT maintenance may support translation of our RT program for diabetes prevention into community settings.

Low- and high-volume of intensive endurance training significantly improves maximal oxygen uptake after 10-weeks of training in healthy men.

UNLABELLED: Regular exercise training improves maximal oxygen uptake (VO2max), but the optimal intensity and volume necessary to obtain maximal benefit remains to be defined. A growing body of evidence suggests that exercise training with low-volume but high-intensity may be a time-efficient means to achieve health benefits. In the present study, we measured changes in VO2max and traditional cardiovascular risk factors after a 10 wk. training protocol that involved three weekly high-intensity interval sessions. One group followed a protocol which consisted of 4×4 min at 90% of maximal heart rate (HRmax) interspersed with 3 min active recovery at 70% HRmax (4-AIT), the other group performed a single bout protocol that consisted of 1×4 min at 90% HRmax (1-AIT). Twenty-six inactive but otherwise healthy overweight men (BMI: 25-30, age: 35-45 y) were randomized to either 1-AIT (n = 11) or 4-AIT (n = 13). After training, VO2max increased by 10% (∼5.0 mL⋅kg(-1)⋅min(-1)) and 13% (∼6.5 mL⋅kg(-1)⋅min(-1)) after 1-AIT and 4-AIT, respectively (group difference, p = 0.08). Oxygen cost during running at a sub-maximal workload was reduced by 14% and 13% after 1-AIT and 4-AIT, respectively. Systolic blood pressure decreased by 7.1 and 2.6 mmHg after 1-AIT and 4-AIT respectively, while diastolic pressure decreased by 7.7 and 6.1 mmHg (group difference, p = 0.84). Both groups had a similar ∼5% decrease in fasting glucose. Body fat, total cholesterol, LDL-cholesterol, and ox-LDL cholesterol only were significantly reduced after 4-AIT. Our data suggest that a single bout of AIT performed three times per week may be a time-efficient strategy to improve VO2max and reduce blood pressure and fasting glucose in previously inactive but otherwise healthy middle-aged individuals. The 1-AIT type of exercise training may be readily implemented as part of activities of daily living and could easily be translated into programs designed to improve public health. TRIAL REGISTRATION: ClinicalTrials.govNCT00839579.

Increasing physical activity of high intensity to reduce the prevalence of chronic diseases and improve public health.

High incidence and prevalence of chronic diseases, increasing obesity and inactivity as well as rising health expenditure represent a set of developments that cannot be considered sustainable, and will have dire long-term consequences given the increasing proportion of elderly people in our society. Based on a review of the experiences from previous large scale population-based prevention programs and the documented effects of increased physical activity and cardiorespiratory fitness on chronic diseases and its risk factors, we argue that increased physical activity, especially vigorous physical activity, is a major way to reduce the prevalence of chronic diseases and improve public health. We conclude that a coordinated population-based intervention program for improved health through increased physical activity in the entire population, with a special focus on high intensity exercise, urgently needs to be implemented nationally and internationally.

Small changes approach promotes initial and continued weight loss with a phone-based follow-up: nine-month outcomes from ASPIRES II.

PURPOSE: To examine the impact of a small-changes weight loss program across a 3-month intervention followed by a 6-month follow-up program. DESIGN: A one-group pre-post intervention study. SETTING: Medium-sized Southwestern university. PARTICIPANTS: Twenty-five obese adult women (mean body mass index [BMI]  =  31.8 kg/m(2), standard deviation [SD]  =  4.9). INTERVENTION: Participants were asked to choose and adopt small changes in their diet and physical activity relative to baseline during weekly group-based meetings over 3 months. Participants then received bi-weekly phone calls across a 6-month follow-up period. MEASURES: Weight change was the primary outcome. Secondary outcomes included waist circumference, daily step count, and caloric intake. ANALYSES: Intention-to-treat analysis of change from baseline and completers-only analysis (n  =  22) for secondary outcomes. RESULTS: Participants achieved clinically significant weight loss (mean [M]  =  -3.2 kg, standard error [SE]  =  .47 kg, p < .001) across the initial small changes treatment program. Moreover, participants continued to lose weight across the 6-month phone-based follow-up program (M  =  -2.1 kg, SE  =  .83 kg, p < .017), totaling >5% weight loss across the 9-month program (M  =  5.3 kg, SE  =  1.1 kg, p < .001). CONCLUSION: Using a small changes approach, participants achieved weight loss in an initial group-based program, which continued with minimal phone-based follow-up. Larger randomized studies comparing a small changes approach to traditional obesity treatment are warranted.

Aging and the social cognitive determinants of physical activity behavior and behavior change: evidence from the guide to health trial.

Part one of this study investigated the effect of aging on social-cognitive characteristics related to physical activity (PA) among adults in the baseline phase of a health promotion intervention. Participants' questionnaire responses and activity logs indicated PA levels and self-efficacy declined with age, while social support and the use of self-regulatory behaviors (e.g., goal setting, planning, and keeping track) increased. With age participants were also less likely to expect PA to interfere with their daily routines and social obligations. Part two of the study was among overweight/obese, inactive participants completing the intervention; it examined whether improvements in psychosocial variables might counteract declining PA associated with age. After treatment, participants were more active and decreased body weight regardless of age, and improved self-efficacy, outcome expectations, and self-regulatory behaviors. In a causal model, increases in self-efficacy at 7-months lead to increased PA levels and, albeit marginally, weight loss at 16 months; increased PA was associated with greater weight loss. Aging adults who were more confident exercised more and as a result lost more weight. This longitudinal study suggests interventions that offset the effect of aging on self-efficacy may be more successful in helping older participants become more active and avoid weight gain.

Web-based guide to health: relationship of theoretical variables to change in physical activity, nutrition and weight at 16-months.

BACKGROUND: Evaluation of online health interventions should investigate the function of theoretical mechanisms of behavior change in this new milieu. OBJECTIVES: To expand our understanding of how Web-based interventions influence behavior, we examined how changes at 6 months in participants' psychosocial characteristics contributed to improvements at 16 months in nutrition, physical activity (PA), and weight management as a result of the online, social cognitive theory (SCT)-based Guide to Health intervention (WB-GTH). METHODS: We conducted recruitment, enrollment, and assessments online with 272 of 655 (41.5%) participants enrolling in WB-GTH who also completed 6- and 16-month follow-up assessments. Participants' mean age was 43.68 years, 86% were female, 92% were white, mean education was 17.45 years, median income was US $85,000, 84% were overweight or obese, and 73% were inactive. Participants received one of two equally effective versions of WB-GTH. Structural equation analysis of theoretical models evaluated whether psychosocial constructs targeted by WB-GTH contributed to observed health behavior changes. RESULTS: The longitudinal model provided good fit to the data (root mean square error of approximation <.05). Participants' weight loss at 16 months was predicted by improvements in their PA (beta(total) = -.34, P = .01), consumption of fruits and vegetables (F&V) (beta(total) = -.20, P = .03) and calorie intake (beta(total) = .15, P = .04). Improvements at 6 months in PA self-efficacy (beta(total) = -.10, P = .03), PA self-regulation (beta(total) = -.15, P = .01), nutrition social support (beta(total) = -.08, P = .03), and nutrition outcome expectations (beta(total) = .08, P = .03) also contributed to weight loss. WB-GTH users with increased social support (beta(total) = .26, P = .04), self-efficacy (beta(total) = .30, P = .01), and self-regulation (beta(total) = .45, P = .004) also exhibited improved PA levels. Decreased fat and sugar consumption followed improved social support (beta(total) = -.10, P = .02), outcome expectations (beta(total) = .15, P = .007), and self-regulation (beta(total) = -.14, P = .008). Decreased calorie intake followed increased social support (beta(total) = -.30, P < .001). Increased F&V intake followed improved self-efficacy (beta(total) = .20, P = .01), outcome expectations (beta(total) = -.29, P = .002), and self-regulation (beta(total) = .27, P = .009). Theorized indirect effects within SCT variables were also supported. CONCLUSIONS: The WB-GTH influenced behavior and weight loss in a manner largely consistent with SCT. Improving social support, self-efficacy, outcome expectations, and self-regulation, in varying combinations, led to healthier diet and exercise habits and concomitant weight loss. High initial levels of self-efficacy may be characteristic of Web-health users interested in online interventions and may alter the function of SCT in these programs. Researchers may find that, although increased self-efficacy enhances program outcomes, participants whose self-efficacy is tempered by online interventions may still benefit. TRIAL REGISTRATION: Clinicaltrials.gov NCT00128570; http://clinicaltrials.gov/ct2/show/NCT00128570 (Archived by WebCite at http://www.webcitation.org/5vgcygBII).

Social cognitive determinants of nutrition and physical activity among web-health users enrolling in an online intervention: the influence of social support, self-efficacy, outcome expectations, and self-regulation.

BACKGROUND: The Internet is a trusted source of health information for growing majorities of Web users. The promise of online health interventions will be realized with the development of purely online theory-based programs for Web users that are evaluated for program effectiveness and the application of behavior change theory within the online environment. Little is known, however, about the demographic, behavioral, or psychosocial characteristics of Web-health users who represent potential participants in online health promotion research. Nor do we understand how Web users' psychosocial characteristics relate to their health behavior-information essential to the development of effective, theory-based online behavior change interventions. OBJECTIVE: This study examines the demographic, behavioral, and psychosocial characteristics of Web-health users recruited for an online social cognitive theory (SCT)-based nutrition, physical activity, and weight gain prevention intervention, the Web-based Guide to Health (WB-GTH). METHODS: Directed to the WB-GTH site by advertisements through online social and professional networks and through print and online media, participants were screened, consented, and assessed with demographic, physical activity, psychosocial, and food frequency questionnaires online (taking a total of about 1.25 hours); they also kept a 7-day log of daily steps and minutes walked. RESULTS: From 4700 visits to the site, 963 Web users consented to enroll in the study: 83% (803) were female, participants' mean age was 44.4 years (SD 11.03 years), 91% (873) were white, and 61% (589) were college graduates; participants' median annual household income was approximately US $85,000. Participants' daily step counts were in the low-active range (mean 6485.78, SD 2352.54) and overall dietary levels were poor (total fat g/day, mean 77.79, SD 41.96; percent kcal from fat, mean 36.51, SD 5.92; fiber g/day, mean 17.74, SD 7.35; and fruit and vegetable servings/day, mean 4.03, SD 2.33). The Web-health users had good self-efficacy and outcome expectations for health behavior change; however, they perceived little social support for making these changes and engaged in few self-regulatory behaviors. Consistent with SCT, theoretical models provided good fit to Web-users' data (root mean square error of the approximation [RMSEA] < .05). Perceived social support and use of self-regulatory behaviors were strong predictors of physical activity and nutrition behavior. Web users' self-efficacy was also a good predictor of healthier levels of physical activity and dietary fat but not of fiber, fruits, and vegetables. Social support and self-efficacy indirectly predicted behavior through self-regulation, and social support had indirect effects through self-efficacy. CONCLUSIONS: Results suggest Web-health users visiting and ultimately participating in online health interventions may likely be middle-aged, well-educated, upper middle class women whose detrimental health behaviors put them at risk of obesity, heart disease, some cancers, and diabetes. The success of Internet physical activity and nutrition interventions may depend on the extent to which they lead users to develop self-efficacy for behavior change, but perhaps as important, the extent to which these interventions help them garner social-support for making changes. Success of these interventions may also depend on the extent to which they provide a platform for setting goals, planning, tracking, and providing feedback on targeted behaviors.

Guide to Health: A Randomized Controlled Trial of the Effects of a Completely WEB-Based Intervention on Physical Activity, Fruit and Vegetable Consumption, and Body Weight.

BACKGROUND: Theory-based, efficacious, long-term, completely Internet-based interventions are needed to induce favorable shifts in health behaviors and prevent weight gain. PURPOSE: To assess nutrition, physical activity, and, secondarily, body weight outcomes in the tailored, social cognitive theory Guide to Health (WB-GTH) program with all recruitment, assessment, and intervention performed on the Internet. METHODS: The focus of the efficacy study was engaged participants who completed 3 or more program modules plus baseline, 6-months post and, 16-months follow-up assessments (n = 247). To be eligible, participants needed to be between 18-63 years of age, with a BMI between 23-39, sedentary to low-active but otherwise healthy. Participant had a mean age of 45.5 years (10.3), 86.2% were female, with 8.5% from minority groups, with a mean 17.5 (3.0) years of education, and had a median annual household income of about $85k. Nevertheless, about 83% were overweight or obese and about 75% were sedentary (i.e., <5000 steps/day) or had low levels of activity (i.e., 5,000 - 7499 steps/day). Participants were randomized to the WB-GTH-Basic intervention or WB-GTH-Enhanced intervention. Content, overall target behaviors, program goals and strategies were the same in the two interventions with the difference that Basic included a generic feedback and planning approach and Enhanced included a highly tailored planning and feedback approach. Participants reported at assessments pedometer step counts to assess physical activity, bodyweight from a scale provided, and fruit and vegetable (F&V) servings were assessed from food frequency questionnaires completed online. RESULTS: Participants in both Basic and Enhanced at follow-up increased physical activity by about 1400 steps/day, lost about 3% of bodyweight, and increased F&V by about 1.5 serving/day. There was evidence that the least physically active, those who were obese, and those with poorest nutrition made greater long-term improvements. CONCLUSIONS: Given similar outcomes for Basic and Enhanced, a relatively simple entirely Internet-based program can help people improve health behaviors and prevent weight gain.

Uncomplicated resistance training and health-related outcomes: evidence for a public health mandate.

Compared to aerobic training (AT), resistance training (RT) has received far less attention as a prescription for general health. However, RT is as effective as AT in lowering risk for cardiovascular disease, diabetes, and other diseases. There is a clear ability of RT, in contrast to AT, to promote gains, maintenance, or slow loss of skeletal muscle mass/strength. Thus, as an antisarcopenic exercise treatment, RT is of greater benefit than AT; given the aging of our population, this is of primary importance. In our view, a substantial barrier to greater adoption of RT is the incorrectly perceived importance of variables such as external load, intensity, and volume, leading to complex, difficult-to-follow regimes. We propose a more feasible and easier-to-adhere-to paradigm for RT that could affect how RT is viewed and adopted as a prescription for public health.