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Michael G Perri

Publications and source records attributed to Michael G Perri.

16 recordsLinked to original sources
PubMed2006

Low-fat dietary pattern and risk of colorectal cancer: the Women's Health Initiative Randomized Controlled Dietary Modification Trial.

CONTEXT: Observational studies and polyp recurrence trials are not conclusive regarding the effects of a low-fat dietary pattern on risk of colorectal cancer, necessitating a primary prevention trial. OBJECTIVE: To evaluate the effects of a low-fat eating pattern on risk of colorectal cancer in postmenopausal women. DESIGN, SETTING, AND PARTICIPANTS: The Women's Health Initiative Dietary Modification Trial, a randomized controlled trial conducted in 48,835 postmenopausal women aged 50 to 79 years recruited between 1993 and 1998 from 40 clinical centers throughout the United States. INTERVENTIONS: Participants were randomly assigned to the dietary modification intervention (n = 19,541; 40%) or the comparison group (n = 29,294; 60%). The intensive behavioral modification program aimed to motivate and support reductions in dietary fat, to increase consumption of vegetables and fruits, and to increase grain servings by using group sessions, self-monitoring techniques, and other tailored and targeted strategies. Women in the comparison group continued their usual eating pattern. MAIN OUTCOME MEASURE: Invasive colorectal cancer incidence. RESULTS: A total of 480 incident cases of invasive colorectal cancer occurred during a mean follow-up of 8.1 (SD, 1.7) years. Intervention group participants significantly reduced their percentage of energy from fat by 10.7% more than did the comparison group at 1 year, and this difference between groups was mostly maintained (8.1% at year 6). Statistically significant increases in vegetable, fruit, and grain servings were also made. Despite these dietary changes, there was no evidence that the intervention reduced the risk of invasive colorectal cancer during the follow-up period. There were 201 women with invasive colorectal cancer (0.13% per year) in the intervention group and 279 (0.12% per year) in the comparison group (hazard ratio, 1.08; 95% confidence interval, 0.90-1.29). Secondary analyses suggested potential interactions with baseline aspirin use and combined estrogen-progestin use status (P = .01 for each). Colorectal examination rates, although not protocol defined, were comparable between the intervention and comparison groups. Similar results were seen in analyses adjusting for adherence to the intervention. CONCLUSION: In this study, a low-fat dietary pattern intervention did not reduce the risk of colorectal cancer in postmenopausal women during 8.1 years of follow-up. CLINICAL TRIALS REGISTRATION: ClinicalTrials.gov Identifier: NCT00000611.

Adenoma↗
PubMed2006

Low-fat dietary pattern and risk of cardiovascular disease: the Women's Health Initiative Randomized Controlled Dietary Modification Trial.

CONTEXT: Multiple epidemiologic studies and some trials have linked diet with cardiovascular disease (CVD) prevention, but long-term intervention data are needed. OBJECTIVE: To test the hypothesis that a dietary intervention, intended to be low in fat and high in vegetables, fruits, and grains to reduce cancer, would reduce CVD risk. DESIGN, SETTING, AND PARTICIPANTS: Randomized controlled trial of 48,835 postmenopausal women aged 50 to 79 years, of diverse backgrounds and ethnicities, who participated in the Women's Health Initiative Dietary Modification Trial. Women were randomly assigned to an intervention (19,541 [40%]) or comparison group (29,294 [60%]) in a free-living setting. Study enrollment occurred between 1993 and 1998 in 40 US clinical centers; mean follow-up in this analysis was 8.1 years. INTERVENTION: Intensive behavior modification in group and individual sessions designed to reduce total fat intake to 20% of calories and increase intakes of vegetables/fruits to 5 servings/d and grains to at least 6 servings/d. The comparison group received diet-related education materials. MAIN OUTCOME MEASURES: Fatal and nonfatal coronary heart disease (CHD), fatal and nonfatal stroke, and CVD (composite of CHD and stroke). RESULTS: By year 6, mean fat intake decreased by 8.2% of energy intake in the intervention vs the comparison group, with small decreases in saturated (2.9%), monounsaturated (3.3%), and polyunsaturated (1.5%) fat; increases occurred in intakes of vegetables/fruits (1.1 servings/d) and grains (0.5 serving/d). Low-density lipoprotein cholesterol levels, diastolic blood pressure, and factor VIIc levels were significantly reduced by 3.55 mg/dL, 0.31 mm Hg, and 4.29%, respectively; levels of high-density lipoprotein cholesterol, triglycerides, glucose, and insulin did not significantly differ in the intervention vs comparison groups. The numbers who developed CHD, stroke, and CVD (annualized incidence rates) were 1000 (0.63%), 434 (0.28%), and 1357 (0.86%) in the intervention and 1549 (0.65%), 642 (0.27%), and 2088 (0.88%) in the comparison group. The diet had no significant effects on incidence of CHD (hazard ratio [HR], 0.97; 95% confidence interval [CI], 0.90-1.06), stroke (HR, 1.02; 95% CI, 0.90-1.15), or CVD (HR, 0.98; 95% CI, 0.92-1.05). Excluding participants with baseline CVD (3.4%), the HRs (95% CIs) for CHD and stroke were 0.94 (0.86-1.02) and 1.02 (0.90-1.17), respectively. Trends toward greater reductions in CHD risk were observed in those with lower intakes of saturated fat or trans fat or higher intakes of vegetables/fruits. CONCLUSIONS: Over a mean of 8.1 years, a dietary intervention that reduced total fat intake and increased intakes of vegetables, fruits, and grains did not significantly reduce the risk of CHD, stroke, or CVD in postmenopausal women and achieved only modest effects on CVD risk factors, suggesting that more focused diet and lifestyle interventions may be needed to improve risk factors and reduce CVD risk. CLINICAL TRIALS REGISTRATION: ClinicalTrials.gov Identifier: NCT00000611.

Aged↗
PubMed2006

Relation of BMI and physical activity to sex hormones in postmenopausal women.

OBJECTIVE: Levels of estrogen, androgen, and prolactin have been related to risk of postmenopausal breast cancer. However, the determinants of these hormone concentrations are not established. The purpose of this study was to examine correlates of endogenous sex hormones. RESEARCH METHODS AND PROCEDURES: Associations among adiposity, physical activity, and diet and concentrations of estradiol, free estradiol, estrone, testosterone, free testosterone, sex hormone-binding globulin (SHBG), androstenedione, dehydroepiandrosterone, dehydroepiandrosterone sulfate, and prolactin were evaluated in 267 postmenopausal women randomly selected from the Women's Health Initiative Dietary Modification Trial. RESULTS: In multiple regression analyses on log-transformed hormones, BMI was positively associated with estrone (beta = 0.031, p < 0.001), estradiol (beta = 0.048, p < 0.001), free estradiol (beta = 0.062, p < 0.001), free testosterone (beta = 0.017, p = 0.02), and prolactin (beta = 0.012, p = 0.02) and negatively associated with SHBG (beta = -0.02, p = 0.001). Total physical activity (metabolic equivalent tasks per week) was negatively associated with concentrations of estrone, estradiol, and androstenedione (beta = -0.006, -0.007, and -0.005, respectively, all p < or = 0.05). Using a composite variable of BMI and physical activity dichotomized by median values, women with high BMI/low physical activity had a mean estrone concentration of 28.8 pg/mL, compared with 24.1, 19.9, and 18.4 pg/mL for women with high BMI/high physical activity, low BMI/low physical activity, and low BMI/high physical activity, respectively (p trend < 0.001). Similar trends were observed for estradiol and free estradiol and, in inverse, for SHBG. DISCUSSION: These associations may, in part, explain the positive associations between overweight/obesity and a sedentary lifestyle on breast cancer risk.

Aged↗
PubMed2005

Prescribing exercise at varied levels of intensity and frequency: a randomized trial.

BACKGROUND: Regular physical activity produces beneficial effects on health, but the exercise prescription needed to improve cardiovascular disease risk factors in free-living sedentary individuals remains unclear. METHODS: Sedentary adults (N = 492, 64.0% women) were randomized to 1 of 4 exercise-counseling conditions or to a physician advice comparison group. The duration (30 minutes) and type (walking) of exercise were held constant, while exercise intensity and frequency were manipulated to form 4 exercise prescriptions: moderate intensity-low frequency, moderate intensity-high frequency (HiF), hard intensity (HardI)-low frequency, and HardI-HiF. Comparison group participants received physician advice and written materials regarding recommended levels of exercise for health. Outcomes included 6- and 24-month changes in cardiorespiratory fitness (maximum oxygen consumption), high-density lipoprotein cholesterol (HDL-C) level, and the total cholesterol-HDL-C ratio. RESULTS: At 6 months, the HardI-HiF, HardI-low-frequency, and moderate-intensity-HiF conditions demonstrated significant increases in maximum oxygen consumption (P < .01 for all), but only the HardI-HiF condition showed significant improvements in HDL-C level (P < .03), total cholesterol-HDL-C ratio (P < .04), and maximum oxygen consumption (P < .01) compared with physician advice. At 24 months, the increases in maximum oxygen consumption remained significantly higher than baseline in the HardI-HiF, HardI-low-frequency, and moderate-intensity-HiF conditions and in the HardI-HiF group compared with physician advice (P < .01 for all), but no significant effects on HDL-C level (P = .57) or total cholesterol-HDL-C ratio (P = .64) were observed. CONCLUSIONS: Exercise counseling with a prescription for walking at either a HardI or a HiF produced significant long-term improvements in cardiorespiratory fitness. More exercise or the combination of HardI plus HiF exercise may provide additional benefits, including larger fitness changes and improved lipid profiles.

Adult↗
PubMed2005

Changing weight-loss expectations: a randomized pilot study.

Participants in weight-loss programs expect unreasonably large weight losses and believe that such reductions will produce dramatic improvements in their lives. The failure to achieve such benefits may contribute to poor maintenance of lost weight. This randomized pilot study investigated a new cognitive-behavioral intervention designed to modify unrealistic expectations regarding weight loss and its likely impact on appearance, attractiveness, and self-esteem. Twenty-eight overweight and obese young women who completed 10 sessions of standard behavioral weight-loss treatment were randomly assigned to 10 additional sessions of either standard behavioral (SB) treatment or a reformulated cognitive-behavioral (RCB) treatment. At posttreatment, the RCB intervention produced more realistic weight-loss expectations, decreased participants' motivation to lose weight as a means of improving self-confidence, and increased their overall self-esteem, compared with the SB condition (all p's<.05). The mean posttreatment weight changes achieved in the SB (-6.2+/-4.5 kg) and RCB (-5.5+/-3.6 kg) conditions were equivalent, as were the amounts of weight regained during a 6-month follow-up (SB=2.3+/-2.7 kg; RCB=1.5+/-1.7 kg). Collectively, these findings indicate that the RCB intervention was effective in changing unrealistic weight-loss expectations, but it did not produce significantly better maintenance of lost weight than did the SB intervention.

Adolescent↗
PubMed2004

Effects of exercise on emerging and traditional cardiovascular risk factors.

BACKGROUND: Common cardiovascular disease risk factors (e.g., insulin and aerobic fitness) are improved with exercise; however, few studies have addressed the potential for training to modify emerging cardiovascular disease risk factors such as homocysteine and high-sensitivity C-reactive protein. METHODS: Sedentary adults (n = 324, 48.9 +/- 8.4 years) were randomized to four groups differing in training intensity (moderate = 45-55% or high = 65-75% of heart rate reserve) and frequency (low = 3-4, 30-min sessions/week or high = 5-7, 30 min-sessions/week). RESULTS: Within-group changes in homocysteine, insulin, and aerobic fitness were significant (all P < 0.0125). Furthermore, homocysteine increased in the high-intensity-low-frequency (0.98 +/- 2.32 micromol/L) and high-intensity-high-frequency (0.93 +/- 2.56 micromol/L) groups, while aerobic fitness increased in the moderate-intensity-high-frequency (0.99 +/- 2.01 mL min(-1) kg(-1)) and high-intensity-high-frequency (1.77 +/- 2.97 mL min(-1) kg(-1)) groups (all P < 0.003). The change in aerobic fitness was greater in the high-intensity-high-frequency compared to the moderate-intensity-low-frequency group (1.77 +/- 2.97 vs. 0.36 +/- 2.10 mL min(-1) kg(-1), P = 0.0014) (effect size estimate = 0.60 mL min(-1) kg(-1)). The main effects for intensity, with respect to the change in insulin (effect size estimate = 0.46 microU/mL), and frequency, with respect to the change in aerobic fitness (effect size estimate = 0.38 mL min(-1) kg(-1)), were significant (P < 0.0125). CONCLUSION: Although frequent bouts of higher intensity exercise were particularly effective in reducing fasting insulin and improving fitness, they resulted in slightly increased homocysteine levels.

Adult↗
PubMed2004

Body mass index and alcohol use.

BACKGROUND: Obesity, inactivity and being overweight are leading causes of morbidity and mortality in the United States. The relationship between eating, overeating, and addiction have been discussed, debated and more recently investigated. We have hypothesized that drugs of abuse compete with food for brain reward sites. Overeating and obesity may act as protective factors reducing drug reward and addiction. METHODS: In the first part of this study, 374 charts of all active weight management patients in a 12-month period were examined. Demographic information, laboratory testing, psychiatric diagnostic interview, alcohol and drug history were reviewed. A detailed alcohol use, abuse, dependence history was present in 298 charts as part of the pre-bariatric evaluation. The relationship between BMI and alcohol use among female patients (n = 298) was then analyzed. RESULTS: We found a significant (p <.05) inverse relationship between BMI and alcohol consumption. The more obese the patient was, the less alcohol they consumed. The percentage of women who consumed alcohol in the past year decreased as BMI level increased. These results confirmed our surgeons' perception that it is rare to find a morbidly obese patient excluded for bariatric surgery because of excessive alcohol consumption. CONCLUSIONS: Obese patients have lower rates of alcohol use than found in the general population of women. As BMI increases, lower rates of alcohol consumption are found. Overeating may compete with alcohol for brain reward sites, making alcohol ingestion less reinforcing.

Adolescent↗
PubMed2004

A randomized pilot trial of exercise promotion in sedentary African-American adults.

This study compared the effects of 3 home-based exercise promotion programs for African Americans. Sixty, sedentary African-American adults were randomly assigned to either a standard behavioral counseling group (N=22), a culturally sensitive counseling group (N=20), or a physician advice comparison group (N=10). The key study outcomes measured at baseline and after 6 months included cardiorespiratory fitness and physical activity. Acculturation was examined as a moderating variable. Participants in all 3 groups reported significant increases in walking, but significant improvements in fitness were observed only in the 2 intervention groups. Participants in the culturally sensitive intervention reported significantly higher levels of exercise social support compared to members of the other 2 groups. These findings show that home-based exercise counseling programs are effective for improving fitness, yet the addition of culturally tailored components may not be sufficient to produce better outcomes than standard behavioral counseling.

Acculturation↗
PubMed2003

Comparison of perceived health to physiological measures of health in Black and White women.

BACKGROUND: Obesity and sedentary lifestyles are prevalent among minority women. This study compared perceived and physiological measures of health in 35 non-Hispanic Black (NHB) and 155 non-Hispanic White (NHW) sedentary women. METHODS: Self-perception of body weight, physical shape and appearance, physical fitness, and eating habits were assessed via questionnaire using 10-point scales (1 = poor, 10 = excellent), and height, weight, aerobic capacity (V(O(2))(max)), and 4-day food records were directly measured. RESULTS: Although body mass index (BMI, 30.3 +/- 5.3 vs 27.2 +/- 4.5 kg/m(2)) and weight (82.7 +/- 16.5 vs 73.1 +/- 12.9 kg) were greater (both P = 0.0001) in NHB, groups were similar in self-perception of physical shape and appearance and weight. V(O(2))(max) was lower in NHB compared to NHW (20.7 +/- 4.5 vs 23.5 +/- 4.6 ml x kg(-1) x min(-1), P = 0.002), despite no difference between groups in self-perception of physical fitness. Finally, there was no difference between groups for self-perception of eating habits and percentage of calories derived from fat (%fat). The results were unchanged after adjusting for age, education, and income, except that %fat was greater in NHB compared to NHW (35.7 +/- 6.3 vs 33.8 +/- 6.9%, P = 0.03). CONCLUSIONS: Although NHB were heavier, more obese, less fit, and consumed a greater %fat than NHW, they perceived their weight, physical shape and appearance, physical fitness, and eating habits to be no worse than those of their White counterparts. The perceptions of NHB regarding their weight, fitness, and eating habits may represent barriers to change.

Adult↗
PubMed2003

Minimal intervention programs for weight loss in heart transplant candidates: a preliminary examination.

CONTEXT: Overweight can be a contraindication for cardiac transplantation, and empirical findings suggest that obesity may pose serious posttransplant health risks that can increase morbidity and mortality. OBJECTIVE: This study assessed the relative effectiveness of 2 minimal intervention programs to assist weight loss in heart transplant candidates. DESIGN: A randomized trial was employed to assess changes in body weight. SETTING: A large, tertiary care hospital in a Southern locale. PATIENTS: Forty-three heart transplant candidates (74% men, 79% married, 86% white), with a mean pretreatment body mass index of 32.4 (SD = 4.4). INTERVENTIONS: Patients were randomly assigned to a bibliotherapy weight-loss program or a bibliotherapy plus telephone contact weight-loss program. MAIN OUTCOME MEASURES: Change in body weight over 3 months and return rate of measures of program adherence (3-day food diaries and self-monitoring postcards). RESULTS: An intent-to-treat analysis showed a significant weight loss at posttreatment for the sample as a whole. Within-group analyses indicated that a significant weight change (P < .05) in the telephone contact group (mean [SD] = -2.76 [4.96] kg) but not the bibliotherapy-only group (mean [SD] = -1.02 [2.97] kg). Participants in the telephone contact group returned more 3-day food diaries and self-monitoring postcards, with pounds lost significantly correlated with the number of completed self-monitoring postcards. These findings suggest that a minimal intervention program involving information plus limited professional contact may represent a viable approach to assisting overweight transplant candidates in weight management.

Adult↗
PubMed2003

Exercise training, without weight loss, increases insulin sensitivity and postheparin plasma lipase activity in previously sedentary adults.

OBJECTIVE: To determine the effects of exercise, without weight loss, on insulin sensitivity (S(I)), postheparin plasma lipase activity (PHPL), intravenous fat clearance rate (K(2)), and fasting lipids in sedentary adults. RESEARCH DESIGN AND METHODS: At baseline and after 6 months of walk training (intensity 45-55 or 65-75% heart rate reserve, frequency 3-4 or 5-7 days/week, duration 30 min/session), anthropometric indexes, S(I), PHPL, K(2), and fasting lipids were measured in 18 sedentary adults (12 women, 6 men; 51.9 +/- 5.8 years of age, BMI 28.9 +/- 4.6 kg/m(2)). RESULTS: Exercise increased S(I) (2.54 +/- 2.74 vs. 4.41 +/- 3.30 microU ml(-1) x min(-1), P < 0.005) and both lipoprotein lipase (LPL) (1890 +/- 1380 vs. 4926 +/- 1858 nEq free fatty acid [FFA]. ml(-1). h(-1)) and hepatic lipase (HL) activities (3326 +/- 1605 vs. 4636 +/- 1636 nEq FFA. ml(-1) x h(-1)) (both P < 0.001), without altering BMI, waist circumference, K(2), or fasting lipids. Correlations between changes in LPL and the total:HDL cholesterol ratio (r = -0.54) and changes in the LPL:HL ratio and waist circumference (r = -0.50) were significant (P < 0.05). CONCLUSIONS: Exercise, without weight loss, increases S(I) and PHPL activity in previously sedentary adults, without changing K(2) or fasting lipid levels. Furthermore, increased LPL is associated with a decreased total:HDL ratio, and an increased LPL:HL ratio is associated with a decreased waist circumference. Therefore, even modest amounts of exercise in the absence of weight loss positively affect markers of glucose and fat metabolism in previously sedentary, middle-aged adults.

Biomarkers↗
PubMed2002

Walking compared with vigorous exercise for the prevention of cardiovascular events in women.

BACKGROUND: The role of walking, as compared with vigorous exercise, in the prevention of cardiovascular disease remains controversial. Data for women who are members of minority racial or ethnic groups are particularly sparse. METHODS: We prospectively examined the total physical-activity score, walking, vigorous exercise, and hours spent sitting as predictors of the incidence of coronary events and total cardiovascular events among 73,743 postmenopausal women 50 to 79 years of age in the Women's Health Initiative Observational Study. At base line, participants were free of diagnosed cardiovascular disease and cancer, and all participants completed detailed questionnaires about physical activity. We documented 345 newly diagnosed cases of coronary heart disease and 1551 total cardiovascular events. RESULTS: An increasing physical-activity score had a strong, graded, inverse association with the risk of both coronary events and total cardiovascular events. There were similar findings among white women and black women. Women in increasing quintiles of energy expenditure measured in metabolic equivalents (the MET score) had age-adjusted relative risks of coronary events of 1.00, 0.73, 0.69, 0.68, and 0.47, respectively (P for trend, <0.001). In multivariate analyses, the inverse gradient between the total MET score and the risk of cardiovascular events remained strong (adjusted relative risks for increasing quintiles, 1.00, 0.89, 0.81, 0.78, and 0.72, respectively; P for trend <0.001). Walking and vigorous exercise were associated with similar risk reductions, and the results did not vary substantially according to race, age, or body-mass index. A brisker walking pace and fewer hours spent sitting daily also predicted lower risk. CONCLUSIONS: These prospective data indicate that both walking and vigorous exercise are associated with substantial reductions in the incidence of cardiovascular events among postmenopausal women, irrespective of race or ethnic group, age, and body-mass index. Prolonged sitting predicts increased cardiovascular risk.

Aged↗
PubMed2002

The effects of physical and emotional status on adherence to a low-fat dietary pattern in the Women's Health Initiative.

OBJECTIVE: To examine whether the effects of physical and emotional status on adherance to a low-fat (20% energy) dietary pattern are mediated by participation in an intervention program (attending sessions and self-monitoring). DESIGN: The Baron and Kenny mediator model, a series of 4 regression analyses, was used to evaluate whether: a) physical and emotional status predicted program participation, b) program participation predicted dietary adherence, c) physical and emotional status factors predicted dietary adherence, and, ultimately d) the effects of physical and emotional status on dietary adherence were mediated by program participation. SUBJECTS/SETTING: Data from 13,277 postmenopausal women randomly assigned to the low-fat intervention arm of the Women's Health Initiative Dietary Modification Trial. INTERVENTION: The nutrition goals for women randomly assigned to the low-fat intervention were to reduce total fat intake to 20% or less of energy from fat and to consume 5 or more fruit/vegetable servings daily and 6 or more grain servings daily. MAIN OUTCOME MEASURES: Year 1 program participation (degree of attending group sessions and submitting fat scores) and adherence to the low-fat dietary pattern (percent energy from fat) as predicted by baseline physical and emotional status (eight SF-36 Health Survey subscales). RESULTS: Participating in the dietary intervention program reduced (mediated) the negative effect of poorer mental health on dietary adherence by 15%. Additional findings included that a 10% increase in physical functioning increased session attendance by 0.4% (P<.001) and a 10% increase in mental health predicted a decrease in percent energy from fat of 0.3% (P<.001). Program participation had a marked effect on dietary adherence: a 10% increase in session attendance predicted a 1.2% decrease in percent energy from fat (P<.001). APPLICATIONS/CONCLUSIONS: Understanding and using instruments to assess the physical and emotional status of a target population will help dietetic professionals promote healthful dietary change and maintenance.

Adult↗
PubMed2002

Impact of body weight on long-term survival after lung transplantation.

STUDY OBJECTIVES: The purpose of this study was to determine the impact of a pretransplantation determination of body mass index (BMI) on survival after lung transplantation. DESIGN AND PATIENTS: Univariate and multivariate survival analyses of a single institution database consisting of 85 patients who had undergone lung transplantations between March 1994 and October 1998. SETTING: University of Florida Health Science Center. RESULTS: Kaplan-Meier survival curves showed that patients who were obese (ie, BMI, > or = 30) at a pretransplantation assessment had a marked decrease in posttransplantation survival time (log rank, p < 0.05; Wilcoxon, p < 0.05). The final Cox regression model revealed that the most powerful predictors of mortality after lung transplantation were higher pretransplantation BMI and the development of obliterative bronchiolitis. CONCLUSIONS: Our results suggest that the posttransplantation risk for mortality is possibly three times greater for obese patients than for nonobese patients. Additional study is needed to identify the mechanisms for such higher risk in obese patients. Our data also suggest that transplantation centers should not routinely reject underweight patients (ie, BMI, < 18.5) or overweight patients (ie, BMI, 25 to 29.9) for lung transplantation listing solely on the basis of weight, as their outcomes may not be significantly different than patients with normal BMIs.

Adult↗
PubMed2002

Adherence to exercise prescriptions: effects of prescribing moderate versus higher levels of intensity and frequency.

Sedentary adults (N = 379) were randomly assigned in a 2 x 2 design to walk 30 min per day at a frequency of either 3-4 or 5-7 days per week, at an intensity of either 45%-55% or 65%-75% of maximum heart rate reserve. Analyses of exercise accumulated over 6 months showed greater amounts completed in the higher frequency (p = .0001) and moderate intensity (p = .021) conditions. Analyses of percentage of prescribed exercise completed showed greater adherence in the moderate intensity(p = .02) condition. Prescribing a higher frequency increased the accumulation of exercise without a decline in adherence, whereas prescribing a higher intensity decreased adherence and resulted in the completion of less exercise.

Adult↗