Associations between the Dietary Inflammatory Index and Sleep Metrics in the Energy Balance Study (EBS).

(1) Background: Sleep, a physiological necessity, has strong inflammatory underpinnings. Diet is a strong moderator of systemic inflammation. This study explored the associations between the Dietary Inflammatory Index (DII®) and sleep duration, timing, and quality from the Energy Balance Study (EBS). (2) Methods: The EBS (n = 427) prospectively explored energy intake, expenditure, and body composition. Sleep was measured using BodyMedia's SenseWear® armband. DII scores were calculated from three unannounced dietary recalls (baseline, 1-, 2-, and 3-years). The DII was analyzed continuously and categorically (very anti-, moderately anti-, neutral, and pro-inflammatory). Linear mixed-effects models estimated the DII score impact on sleep parameters. (3) Results: Compared with the very anti-inflammatory category, the pro-inflammatory category was more likely to be female (58% vs. 39%, p = 0.02) and African American (27% vs. 3%, p < 0.01). For every one-unit increase in the change in DII score (i.e., diets became more pro-inflammatory), wake-after-sleep-onset (WASO) increased (ßChange = 1.00, p = 0.01), sleep efficiency decreased (ßChange = −0.16, p < 0.05), and bedtime (ßChange = 1.86, p = 0.04) and waketime became later (ßChange = 1.90, p < 0.05). Associations between bedtime and the DII were stronger among African Americans (ßChange = 6.05, p < 0.01) than European Americans (ßChange = 0.52, p = 0.64). (4) Conclusions: Future studies should address worsening sleep quality from inflammatory diets, leading to negative health outcomes, and explore potential demographic differences.

Current and 1-Year Psychological and Physical Effects of Replacing Sedentary Time With Time in Other Behaviors.

INTRODUCTION: Sedentary time is inversely associated with health. Capturing 24 hours of behavior (i.e., sleep, sedentary, light physical activity, and moderate-to-vigorous physical activity) is necessary to understand behavior-health associations. METHODS: Healthy young adults aged 20-35 years (n=423) completed the Profile of Mood States, the Perceived Stress Scale, and dual-energy x-ray absorptiometry and anthropometric measures at baseline and 12 months. Time spent sedentary (total, in prolonged [>30 minutes] and short [≤30 minutes] bouts), in light physical activity (1.5-3.0 METs), moderate-to-vigorous physical activity (>3.0 METs), and asleep, were assessed through SenseWear armband worn 24 hours/day for 10 days at baseline. Isotemporal substitution modeling evaluated cross-sectional and longitudinal psychological and physical health associations of substituting sedentary time with sleep, light physical activity, or moderate-to-vigorous physical activity. Data were collected from 2010 to 2015 and analyzed in 2019. RESULTS: Cross-sectional analyses revealed substituting prolonged sedentary time for sleep was associated with lower stress (standardized ß= -0.11), better mood (-0.12), and lower BMI (-0.10). Substituting total or prolonged sedentary for moderate-to-vigorous physical activity was associated with lower body fat percentage (total, -0.22; prolonged, -0.23) and BMI (-0.40; -0.42). Higher BMI was associated with substituting total or prolonged sedentary for light physical activity (0.15; 0.17); lower BMI with substituting prolonged sedentary for short bouts (-0.09). Prospective analyses indicated substituting total or prolonged sedentary with light physical activity was associated with improved mood (-0.16; -0.14) and lower BMI (-0.15; -0.16); substituting with moderate-to-vigorous physical activity was associated with improved mood (-0.15; -0.15). CONCLUSIONS: Short- and long-term psychological benefits may result from transitioning sedentary time to light physical activity or sleep, whereas increasing moderate-to-vigorous physical activity may be required to influence physical health. TRIAL REGISTRATION: This study is registered at www.clinicaltrials.gov NCT01746186.

The Effect of Exercise Training on Total Daily Energy Expenditure and Body Composition in Weight-Stable Adults: A Randomized, Controlled Trial.

BACKGROUND: The present study examined, among weight-stable overweight or obese adults, the effect of increasing doses of exercise energy expenditure (EEex) on changes in total daily energy expenditure (TDEE), total body energy stores, and body composition. METHODS: Healthy, sedentary overweight/obese young adults were randomized to one of 3 groups for a period of 26 weeks: moderate-exercise (EEex goal of 17.5 kcal/kg/wk), high-exercise (EEex goal of 35 kcal/kg/wk), or observation group. Individuals maintained body weight within 3% of baseline. Pre/postphysical activity between-group measurements included body composition, calculated energy intake, TDEE, energy stores, and resting metabolic rate. RESULTS: Sixty weight-stable individuals completed the protocols. Exercise groups increased EEex in a stepwise manner compared with the observation group (P < .001). There was no group effect on changes in TDEE, energy intake, fat-free mass, or resting metabolic rate. Fat mass and energy stores decreased among the females in the high-exercise group (P = .007). CONCLUSIONS: The increase in EEex did not result in an equivalent increase in TDEE. There was a sex difference in the relationship among energy balance components. These results suggest a weight-independent compensatory response to exercise training with potentially a sex-specific adjustment in body composition.

Relationships between chronotype, social jetlag, sleep, obesity and blood pressure in healthy young adults.

Sleep disturbances, chronotype and social jetlag (SJL) have been associated with increased risks for major chronic diseases that take decades to develop, such as obesity, metabolic syndrome and cardiovascular disease. Potential relationships between poor sleep, chronotype and SJL as they relate to metabolic risk factors for chronic disease have not been extensively investigated. This prospective study examined chronotype, SJL and poor sleep in relation to both obesity and elevated blood pressure among healthy young adults. SJL and objective sleep measures (total sleep time, sleep onset latency, wake after sleep onset and sleep efficiency) were derived from personal rest/activity monitoring (armband actigraphy) among 390 healthy adults 21-35 years old. Participants wore the device for 6-10 days at 6-month intervals over a 2-year period (n = 1431 repeated observations). Chronotypes were categorized into morning, intermediate and evening groups using repeated measures latent class analysis. Means of SJL and sleep measures among latent chronotype groups were compared using partial F-tests in generalized linear mixed models. Generalized linear mixed models also were used to generate odds ratios (ORs) with 95% confidence intervals (CIs) examining the relationship between repeated measures of chronotype, SJL, sleep and concurrent anthropometric outcome measures (body mass index, percentage of body fat, waist-to-hip ratio, waist-to-height ratio), systolic blood pressure and diastolic blood pressure. Sleep latency ≥12 min was associated with increased odds of a high waist-to-height ratio (OR = 1.37; CI: 1.03-1.84). Neither chronotype nor SJL was independently associated with anthropometric outcomes or with blood pressure. Relationships between poor sleep and anthropometric outcomes or blood pressure varied by chronotype. Morning types with total sleep time <6 h, sleep efficiency <85% or wake after sleep onset ≥60 min were more likely to have an increased percentage of body fat, waist-to-hip ratio and waist-to-height ratio relative to those with an intermediate chronotype. Similarly, sleep latency ≥12 min was associated with increased odds of elevated systolic blood pressure (OR = 1.90; CI: 1.15-3.16, pinteraction = 0.02) among morning versus intermediate chronotypes. No relationships between poor sleep and obesity or elevated blood pressure were observed among evening chronotypes. The results from this study among healthy young adults suggest that poor sleep among morning types may be more strongly associated with obesity and elevated blood pressure relative to those with an intermediate (neutral) chronotype. Sleep-related metabolic alterations among different chronotypes warrant further investigation.

Changes in sedentary time are associated with changes in mental wellbeing over 1 year in young adults.

Excessive sedentary time is related to poor mental health. However, much of the current literature uses cross-sectional data and/or self-reported sedentary time, and does not assess factors such as sedentary bout length. To address these limitations, the influence of objectively measured sedentary time including sedentary bout length (i.e. <30 min, ≥30 min) on mood, stress, and sleep, was assessed in 271 healthy adults (49% women; age 27.8 ±â€¯3.7) across a 1-year period between 2011 and 2013 in Columbia, SC. Participants completed the Profile of Mood States and the Perceived Stress Scale, and wore a Sensewear Armband to assess sedentary time, physical activity, and sleep for ten days at baseline and one year. A series of fixed-effects regressions was used to determine the influence of both baseline levels and changes in daily sedentary time (total and in bouts) and physical activity on changes in mood, stress, and sleep over one year. Results showed that across the year, decreases in total sedentary time, and time in both short and long bouts, were associated with improvements in mood, stress and sleep (p < 0.05). Increases in physical activity were only significantly predictive of increases in sleep duration (p < 0.05). Thus, reductions in sedentary time, regardless of bout length, positively influenced mental wellbeing. Specifically, these results suggest that decreasing daily sedentary time by 60 min may significantly attenuate the negative effects of high levels of pre-existing sedentary time on mental wellbeing. Interventions manipulating sedentary behavior are needed to determine a causal link with wellbeing and further inform recommendations.

Energy Intake Derived from an Energy Balance Equation, Validated Activity Monitors, and Dual X-Ray Absorptiometry Can Provide Acceptable Caloric Intake Data among Young Adults.

Background: Assessments of energy intake (EI) are frequently affected by measurement error. Recently, a simple equation was developed and validated to estimate EI on the basis of the energy balance equation [EI = changed body energy stores + energy expenditure (EE)]. Objective: The purpose of this study was to compare multiple estimates of EI, including 2 calculated from the energy balance equation by using doubly labeled water (DLW) or activity monitors, in free-living adults. Methods: The body composition of participants (n = 195; mean age: 27.9 y; 46% women) was measured at the beginning and end of a 2-wk assessment period with the use of dual-energy X-ray absorptiometry. Resting metabolic rate (RMR) was calculated through indirect calorimetry. EE was assessed with the use of the DLW technique and an arm-based activity monitor [Sensewear Mini Armband (SWA); BodyMedia, Inc.]. Self-reported EI was calculated by using dietitian-administered 24-h dietary recalls. Two estimates of EI were calculated with the use of a validated equation: quantity of energy stores estimated from the changes in fat mass and fat-free mass occurring over the assessment period plus EE from either DLW or the SWA. To compare estimates of EI, reporting bias (estimated EI/EE from DLW × 100) and Goldberg ratios (estimated EI/RMR) were calculated. Results: Mean ± SD EEs from DLW and SWA were 2731 ± 494 and 2729 ± 559 kcal/d, respectively. Self-reported EI was 2113 ± 638 kcal/d, EI derived from DLW was 2723 ± 469 kcal/d, and EI derived from the SWA was 2720 ± 730 kcal/d. Reporting biases for self-reported EI, DLW-derived EI, and SWA-derived EI are as follows: -21.5% ± 22.2%, -0.7% ± 18.5%, and 0.2% ± 20.8%, respectively. Goldberg cutoffs for self-reported EI, DLW EI, and SWA EI are as follows: 1.39 ± 0.39, 1.77 ± 0.38, and 1.77 ± 0.38 kcal/d, respectively. Conclusions: These results indicate that estimates of EI based on the energy balance equation can provide reasonable estimates of group mean EI in young adults. The findings suggest that, when EE derived from DLW is not feasible, an activity monitor that provides a valid estimate of EE can be substituted for EE from DLW.

The Influence of Life Events and Psychological Stress on Objectively Measured Physical Activity: A 12-Month Longitudinal Study.

BACKGROUND: This study examined how life event occurrences and stressfulness influence objectively measured light through vigorous physical activity (PA) among young adults. METHODS: Every 3 months over a 12-month period, 404 healthy young adults completed questionnaires on the occurrence and stress of 16 life events and wore an accelerometer for 10 days. RESULTS: A modest positive relationship was seen between cumulative life event occurrences [between effect: ß = 22.2 (9.7) min/d, P = .02] and cumulative stress [between effect: ß = 7.6 (2.9) min/d, P = .01] with light through vigorous PA among men. When considering events individually, job change, starting a first job, beginning a mortgage, and changes in a relationship influenced men's PA. For women, mortgage, starting a first job, job change, and engagement had significant associations. Life event stressfulness influenced PA in women more than in men. For men, stress from changes in a relationship or job positively influenced PA. Stress of a mortgage, quitting a job, changing jobs or a first job influenced women's PA. CONCLUSION: Considering each life event individually was more informative than the summation of life events or summation of stress. Specific life events substantially altered PA, and this change varied by gender, direction of association, and PA intensity and duration.

Persistence of social jetlag and sleep disruption in healthy young adults.

Sleep disruption has been associated with increased risks for several major chronic diseases that develop over decades. Differences in sleep/wake timing between work and free days can result in the development of social jetlag (SJL), a chronic misalignment between a person's preferred sleep/wake schedule and sleep/wake timing imposed by his/her work schedule. Only a few studies have examined the persistence of SJL or sleep disruption over time. This prospective investigation examined SJL and sleep characteristics over a 2-year period to evaluate whether SJL or poor sleep were chronic conditions during the study period. SJL and sleep measures (total sleep time [TST], sleep onset latency [SOL], wake after sleep onset [WASO]), and sleep efficiency [SE]), were derived from armband monitoring among 390 healthy men and women 21-35 years old. Participants wore the armband for periods of 4-10 days at 6-month intervals during the follow-up period (N = 1431 repeated observations). The consistency of SJL or sleep disruption over time was analyzed using generalized linear mixed models (GLMMs) for repeated measures. Repeated measures latent class analysis (RMLCA) was then used to identify subgroups among the study participants with different sleep trajectories over time. Individuals in each latent group were compared using GLMMs to identify personal characteristics that differed among the latent groups. Minor changes in mean SJL, chronotype, or TST were observed over time, whereas no statistically significant changes in SOL, WASO, or SE were observed during the study period. The RMLCA identified two groups of SJL that remained consistent throughout the study (low SJL, mean ± SE: 0.4 ± 0.04 h, 42% of the study population; and high SJL, 1.4 ± 0.03 h, 58%). Those in the SJL group with higher values tended to be employed and have an evening chronotype. Similarly, two distinct subgroups were observed for SOL, WASO, and SE; one group with a pattern suggesting disrupted sleep over time, and another with a consistently normal sleep pattern. Analyses of TST identified three latent groups with relatively short (5.6 ± 1.0 h, 21%), intermediate (6.5 ± 1.0 h, 44%), and long (7.3 ± 1.0 h, 36%) sleep durations, all with temporally stable, linear trajectories. The results from this study suggest that sleep disturbances among young adults can persist over a 2 year period. Latent groups with poor sleep tended to be male, African American, lower income, and have an evening chronotype relative to those with more normal sleep characteristics. Characterizing the persistence of sleep disruption over time and its contributing factors could be important for understanding the role of poor sleep as a chronic disease risk factor.

Psychosocial Determinants of Weight Loss Among Young Adults With Overweight and Obesity: HOW DOES DRIVE FOR THINNESS AFFECT WEIGHT LOSS?

PURPOSE: The ardent wish to lose weight, drive for thinness (DT), might be 1 psychosocial contributor to weight loss (WL) in adults with overweight and obesity. In examining DT as a predictor of WL, it is important to determine whether its predictive value is equal in males and females and whether it exerts its effects primarily through changes in diet or physical activity (PA). METHODS: Two-hundred three men and women with overweight and obesity (body mass index >25 kg/m; aged 21-35 years; 47% female) participated in this 12-month observational study. DT score and demographic information were collected at baseline. Participants were measured at quarterly intervals for objectively measured PA, energy intake, and anthropometrics. Linear mixed regression analyses determined whether DT predicted WL over time and whether these effects were moderated by sex. Followup mediation analyses determined whether the effects of DT on WL could be explained by either changes in diet or PA. RESULTS: Females reported higher DT as compared with males at baseline (P < .001). We observed a significant sex × time × DT interaction on WL (P < .04), such that higher DT predicted WL in males (P < .04), but not in females (P = .54). This effect of DT on WL in overweight and obese males was mediated by changes in PA (indirect effect, -0.43; 95% CI, -1.52 to -0.05), but not changes in energy intake. CONCLUSIONS: Among young adults with overweight and obesity who have higher DT, PA appears to be more important to WL than caloric restriction, particularly in males.

Cross-sectional and longitudinal associations between different exercise types and food cravings in free-living healthy young adults.

INTRODUCTION: An increase in energy intake due to alterations in hedonic appetite sensations may, at least in part, contribute to lower-than-expected weight loss in exercise interventions. The aim of this study was to examine cross-sectional and longitudinal associations between habitual exercise participation and food cravings in free-living young adults. METHODS: A total of 417 adults (49% male, 28 ± 4 years) reported frequency and duration of walking, aerobic exercise, resistance exercise and other exercise at baseline and every 3 months over a 12-month period. Food cravings were assessed via the Control of Eating Questionnaire at baseline and 12-month follow-up. RESULTS: Cross-sectional analyses revealed more frequent cravings for chocolate and a greater difficulty to resist food cravings in women compared to men (p < 0.01). Only with resistance exercise significant sex by exercise interaction effects were observed with favorable responses in men but not in women. Significant main effects were shown for walking and aerobic exercise with exercisers reporting more frequent food cravings for chocolate and fruits and greater difficulty to resist eating compared to non-exercisers (p < 0.05). Longitudinal analyses revealed significant interaction effects for other exercise (p < 0.05) with favorable results in men but not women. Furthermore, significant main effects were observed for aerobic exercise, resistance exercise and total exercise with an increase in exercise being associated with a reduced difficulty to resist food cravings (p < 0.05). DISCUSSION: The association between exercise participation and hedonic appetite sensations varies by exercise type and sex. Even though exercise was associated with more frequent and greater difficulty to food cravings in the cross-sectional analyses, which may be attributed to greater energy demands, longitudinal results indicate beneficial effects of increased exercise on appetite control, particularly in men.

The Association of Physical Activity during Weekdays and Weekend with Body Composition in Young Adults.

Physical activity (PA) is a key contributor in long-term weight management but there remains limited research on the association between weekly PA patterns and weight change. The purpose of the present study was to examine the prospective association between weekly PA patterns and weight change in generally healthy young adults. Anthropometric measurements, including dual X-ray absorptiometry, were obtained every 3 months over a period of one year in 338 adults (53% male). At each measurement time, participants wore a multisensor device for a minimum of 10 days to determine total daily energy expenditure and time spent sleeping, sedentary, in light PA (LPA), in moderate PA (MPA), and in vigorous PA (VPA). PA did not differ between weekdays and the weekend at baseline. Twenty-four-hour sleep time, however, was significantly longer during weekends compared to weekdays, which was associated with less time spent sedentary. Weight loss was associated with a significant increase in LPA at the expense of sedentary time during the weekend but not during weekdays. Regression analyses further revealed an inverse association between change in VPA during the weekend and body composition at 12-month follow-up. Taken together, these results suggest that weekend PA plays an important role in long-term weight management.

Effects of moderate and vigorous physical activity on fitness and body composition.

Current physical activity (PA) guidelines indicate that moderate-intensity (MPA) and vigorous intensity (VPA) PA provide similar benefits when total volume is equal. The present study examined the associations of MPA and VPA with body composition and cardiorespiratory fitness in free-living young adults. A total of 197 young adults (52.8 % male) were followed over a period of 15 months. Body composition was assessed via dual X-ray absorptiometry and time spent in various PA intensities was determined with a multi-sensor device every 3 months. Cardiorespiratory fitness was assessed with a graded exercise test at baseline and 15-months follow-up. Change in VPA was positively associated with cardiorespiratory fitness while MPA had beneficial associations with percent body fat. In overweight/obese participants the association with VO2peak was similar for MVPA bouts and VPA. Even though MPA and VPA have positive associations with overall health, their associations on key health parameters differ.

Anti-inflammatory Dietary Inflammatory Index scores are associated with healthier scores on other dietary indices.

Dietary components are important determinants of systemic inflammation, a risk factor for most chronic diseases. The Dietary Inflammatory Index (DII) was developed to assess dietary inflammatory potential. It was hypothesized that anti-inflammatory DII scores would be associated with "healthier" scores on other dietary indices. The Energy Balance Study is an observational study focusing on energy intake and expenditure in young adults; only baseline data were used for this analysis (n=430). The DII, as well as the Healthy Eating Index-2010 (HEI-2010), the Alternative Healthy Eating Index (AHEI), and the Dietary Approaches to Stop Hypertension Index (DASH) were calculated based on one to three 24-hour dietary recalls. General linear models were used to estimate least square means of the AHEI, HEI-2010, and DASH according to DII quartiles. Those with higher (ie, more proinflammatory) DII scores were more likely to be males, have less than a completed college education, and be younger. In addition, those with higher scores for cognitive restraint for eating or drive for thinness had lower (ie, anti-inflammatory) DII scores. Linear regression analyses indicated that as the DII increased, the AHEI, HEI-2010, and DASH dietary indices decreased (ie, became more unhealthy, all P<.01). The DII is a novel tool that characterizes the inflammatory potential of diet and is grounded in the peer-reviewed literature on diet and inflammation. Findings from the Energy Balance Study indicate that the DII is associated with other dietary indices, but has the added advantage of specifically measuring dietary inflammatory potential, a risk factor for chronic disease.

Is nutrient intake associated with physical activity levels in healthy young adults?

OBJECTIVE: Both physical activity (PA) and diet are important contributors to health and well-being; however, there is limited information on the association of these behaviours and whether observed associations differ by weight. The present study aimed to evaluate whether nutrient intake is associated with PA and if this association varies by weight in young adults. DESIGN: Cross-sectional study to analyse the association between PA and nutrient intake. SETTING: Participants were stratified as normal weight (18·5 kg/m2

Relation of Body's Lean Mass, Fat Mass, and Body Mass Index With Submaximal Systolic Blood Pressure in Young Adult Men.

We examined the association of body composition and body mass index (BMI) with submaximal systolic blood pressure (SSBP) among young adult men. The analysis included 211 men with BMI between 20 and 35 kg/m(2). Total lean mass and fat mass were measured using dual x-ray absorptiometry and lean mass percentage was calculated from the total lean mass. Fat mass index (FMI) and BMI were calculated using height and weight (total fat mass and total weight, respectively) measurements. SSBP was measured at each stage of a graded exercise test. Quintiles of lean mass percentage, FMI, and BMI were created with quintile 1 the lowest and quintile 5 the highest lean mass percentage, FMI, and BMI. Compared with men in lean mass percentage quintile 1, those in quintiles 2, 3, and 4 had significantly lower SSBP, whereas there was no significant difference in SSBP between quintile 1 and 5 at 6, 8, and 10 minutes. Compared with men in FMI quintile 5, those in quintiles 2, 3, and 4 had significantly lower SSBP, whereas there was no significant difference in SSBP between quintile 1 and 5. SSBP among men in lean mass percentage quintile 5 and FMI quintile 1 were still less than lean mass percentage quintile 1 and FMI quintile 5, respectively. There were no significant differences in SSBP across BMI quintiles 1 to 4 but a significantly higher SSBP in quintile 5 compared with quintiles 1 to 4. In conclusion, there was a J-curve pattern between SSBP and components of body composition, whereas, a linear relation between SSBP and BMI.

The Association of Neighborhood Gene-Environment Susceptibility with Cortisol and Blood Pressure in African-American Adults.

BACKGROUND: African-American adults are disproportionately affected by stress-related chronic conditions like high blood pressure (BP), and both environmental stress and genetic risk may play a role in its development. PURPOSE: This study tested whether the dual risk of low neighborhood socioeconomic status (SES) and glucocorticoid genetic sensitivity interacted to predict waking cortisol and BP. METHODS: Cross-sectional waking cortisol and BP were collected from 208 African-American adults who were participating in a follow-up visit as part of the Positive Action for Today's Health trial. Three single-nucleotide polymorphisms were genotyped, salivary cortisol samples were collected, and neighborhood SES was calculated using 2010 Census data. RESULTS: The sample was mostly female (65 %), with weight classified as overweight or obese (M BMI = 32.74, SD = 8.88) and a mean age of 55.64 (SD = 15.21). The gene-by-neighborhood SES interaction predicted cortisol (B = 0.235, p = .001, r (2) = .036), but not BP. For adults with high genetic sensitivity, waking cortisol was lower with lower SES but higher with higher SES (B = 0.87). Lower neighborhood SES was also related to higher systolic BP (B = -0.794, p = .028). CONCLUSIONS: Findings demonstrated an interaction whereby African-American adults with high genetic sensitivity had high levels of waking cortisol with higher neighborhood SES, and low levels with lower neighborhood SES. This moderation effect is consistent with a differential susceptibility gene-environment pattern, rather than a dual-risk pattern. These findings contribute to a growing body of evidence that demonstrates the importance of investigating complex gene-environment relations in order to better understand stress-related health disparities.

Cardiorespiratory Fitness, Body Fatness, and Submaximal Systolic Blood Pressure Among Young Adult Women.

OBJECTIVES: We examined the independent and combined associations of cardiorespiratory fitness (CRF), body fat (BF) percentage (BF%), and body mass index (BMI) with submaximal systolic blood pressure (SSBP) among young adult women. MATERIALS AND METHODS: Analyses included a sample of 211 normotensive women with a BMI between 20 and 35 kg/m(2); BF% was calculated using total BF measured from dual X-ray absorptiometry, CRF was assessed using a graded exercise test, and SSBP was measured at each stage. RESULTS: There was a significant direct association of SSBP with BF% and BMI, whereas an inverse association between SSBP and CRF when adjusted for the covariates. There was no significant association between SSBP and BF% across the stages 1-3 with a borderline significant association at stage 4 when further adjusted for CRF, whereas no association at any of the stages when adjusted for BMI. A borderline significant association between SSBP and BMI was found at stage 1 and significant association at stages 2-4 when additionally adjusted for CRF, whereas the association disappeared at stages 1-2 when adjusted for BF%. The inverse association between SSBP and CRF was eliminated at stages 3-4 when further adjusted for BF% with borderline significant association at stages 1-2. The associations remained significant at the stages 1-2 but not at stages 3-4 after adjusting for BMI. CONCLUSION: CRF, BF%, and BMI seem to have critical roles in determining SSBP with CRF and BF% being more potent at lower intensity exercise, whereas BMI was more strongly associated at higher intensity exercise.