Harmonization of three different accelerometers to classify the 24 h activity cycle.

Increasing interest in measuring key components of the 24 h activity cycle (24-HAC) [sleep, sedentary behavior (SED), light physical activity (LPA), and moderate to vigorous physical activity (MVPA)] has led to a need for better methods. Single wrist-worn accelerometers and different self-report instruments can assess the 24-HAC but may not accurately classify time spent in the different components or be subject to recall errors.Objective. To overcome these limitations, the current study harmonized output from multiple complimentary research grade accelerometers and assessed the feasibility and logistical challenges of this approach.Approach. Participants (n= 108) wore an: (a) ActiGraph GT9X on the wrist, (b) activPAL3 on the thigh, and (c) ActiGraph GT3X+ on the hip for 7-10 d to capture the 24-HAC. Participant compliance with the measurement protocol was compared across devices and an algorithm was developed to harmonize data from the accelerometers. The resulting 24-HAC estimates were described within and across days.Main results. Usable data for each device was obtained from 94.3% to 96.7% of participants and 89.4% provided usable data from all three devices. Compliance with wear instructions ranged from 70.7% of days for the GT3X+ to 93.2% of days for the activPAL3. Harmonized estimates indicated that, on average, university students spent 34% of the 24 h day sleeping, 41% sedentary, 21% in LPA, and 4% in MVPA. These behaviors varied substantially by time of day and day of the week.Significance. It is feasible to use three accelerometers in combination to derive a harmonized estimate the 24-HAC. The use of multiple accelerometers can minimize gaps in 24-HAC data however, factors such as additional research costs, and higher participant and investigator burden, should also be considered.

Diet Quality Outcomes of a Cooperative Extension Diabetes Prevention Program.

OBJECTIVE: The effectiveness of the National Diabetes Prevention Program (DPP) in improving diet quality (DQ) in community settings is largely unknown. This study aimed to evaluate the DQ changes of Extension DPP participants. METHODS: A single-group, repeated-measures design was used to evaluate an Extension-implemented DPP using the PreventT2 curriculum. Participants were overweight adults with or at high risk for prediabetes (n = 88). Weight and DQ (Healthy Eating Index-2015, Dietary Screener Questionnaire) were evaluated using mixed-effects regression. RESULTS: There was no change in the Healthy Eating Index-2015 total score. Predicted fiber, fruit, and vegetable intake increased (P < 0.05) but remained below recommendations. CONCLUSIONS AND IMPLICATIONS: Clinically meaningful DQ changes of Extension DPP participants were limited. The effect of the DPP on DQ in Extension and other implementation settings should be evaluated through randomized controlled trials. Diabetes Prevention Program curriculum revisions that include more specific dietary goals and educational tools may promote greater DQ changes in DPP participants.

Depressive symptoms, but not moderate-to-vigorous physical activity, impacts sexual well-being and menopause-specific quality of life in middle-aged women.

Inadequate physical activity (PA), unhealthy weight status, prevalence of chronic conditions, and psychosocial distress are common in middle-aged women and are linked to reductions in well-being and quality of life. However, their potential interactive effects, specifically on sexual well-being and menopause-specific quality of life (MENQOL), have not been well characterized in postmenopausal women. PURPOSE: To determine if moderate-to-vigorous physical activity (MVPA) and adiposity (%Fat) influence sexual well-being and MENQOL outcomes, controlling for health status (chronic conditions; medications) and psychosocial well-being (depressive symptoms; perceived stress), in postmenopausal women. Postmenopausal women (n = 68, 58.6 ± 3.4 yr, 80.9 percent married/partnered, 51.5 percent overweight/obese, nonsmoking) were recruited through e-mail advertisements and flyers placed throughout the community. Participants were scheduled for two laboratory visits 7-10 days apart where they were objectively assessed for MVPA with accelerometers (in the interim), adiposity via dual-energy X-ray absorptiometry (DXA), and self-report questionnaires to determine health status, depressive symptoms, perceived stress, sexual well-being, and MENQOL. Lower MVPA and higher %Fat were associated with lower physical domain MENQOL (both r = .27, p < .05); health status and psychosocial well-being were not associated (all p > .05). Hierarchical regression analyses revealed 1) greater number of chronic conditions and medications, and depressive symptoms scores predicted less favorable sexual well-being, independent of MVPA and %Fat (standardized ß range =.22-.56, all p < .05), 2) depression was most consistently associated with MENQOL (models p ≤ .001), and 3) greater adiposity augmented the negative influence of depression on the physical domain of MENQOL (ß = .40. p = .002). CONCLUSIONS: PA may influence sexual well-being and MENQOL indirectly through positive impacts on adiposity, chronic conditions, and depressive symptoms in middle-aged postmenopausal women, a sector of the population often afflicted with compromised sexual well-being.

Effect of power training on rate of torque development and spatiotemporal gait parameters post stroke.

BACKGROUND: Maximizing independence and function post-stroke are two common therapy goals. Rate of torque development in lower-extremity muscles was recently reported to be associated with walking speed; however, trainability and subsequent effect on gait is unknown. This study aimed to determine effect of power training on paretic and non-paretic limb torque parameters, spatiotemporal gait parameters, and walking speed in chronic stroke survivors. METHODS: Individuals with chronic stroke (n = 22; 7 females; 62.7 ± 8.8 yrs) completed 24 progressive power-training sessions over 8 weeks with pre and post assessments. Knee extensor strength was assessed via dynamometry with torque parameters measured from maximal voluntary isometric contractions. Gait speed and spatiotemporal gait parameters were assessed via an instrumented gait mat, and a 6-min walk test was performed. FINDINGS: Rate of torque development at 200 ms and peak torque improved 58.6% and 14.1%, respectively, in the quadricep of the paretic limb (p < 0.05); conversely the non-paretic limb was unchanged. On average, self-selected walking speed, fastest-comfortable walking speed, and 6-min walk test improved 21.7%, 21.1%, and 19.5%, respectively (all p < 0.05). Change in torque development at 100 ms in the quadricep of the non-paretic limb was positively associated with improvements in self-selected and fastest-comfortable walking speeds (both r = 0.70, p < 0.05) and 6-min walk (r = 0.78, p < 0.001). INTERPRETATIONS: These findings suggest power training may be an effective intervention for improving torque development in the quadricep of the paretic limb in individuals with chronic stroke. Further research to explore utility and mechanistic aspects of force development for gait function in chronic stroke survivors is warranted.

Implementation of the Diabetes Prevention Program in Georgia Cooperative Extension According to RE-AIM and the Consolidated Framework for Implementation Research.

Increased dissemination of the CDC's Diabetes Prevention Program (DPP) is imperative to reduce type 2 diabetes. Due to its nationwide reach and mission to improve health, Cooperative Extension (Extension) is poised to be a sustainable DPP delivery system. However, research evaluating DPP implementation in Extension remains scant. Extension professionals delivered the DPP in a single-arm hybrid type II effectiveness-implementation study. Semi-structured interviews with Extension professionals were conducted at three time points. The Consolidated Framework for Implementation Research (CFIR) guided interview coding and analysis. Constructs were rated for magnitude and valence and evaluated as facilitators or barriers of RE-AIM (Reach, Effectiveness, Adoption, Implementation, Maintenance) outcomes. The program reached 119 participants, was adopted by 92% (n = 12/13) of trained Extension professionals and was implemented according to CDC standards: all programs exceeded the minimum 22-session requirement (26 ± 2 sessions). The program was effective in achieving weight loss (5.0 ± 5.2%) and physical activity (179 ± 122 min/week) goals. At post-intervention, eight professionals (67%) had begun or planned to maintain the intervention within the next 6 months. Several facilitators were identified, including Extension leadership structure, organizational compatibility, and technical assistance calls. Limited time to recruit participants was the primary barrier. Positive RE-AIM outcomes, facilitated by contextual factors, indicate Extension is an effective and sustainable DPP delivery system. Extension and other DPP implementers should plan strategies that promote communication, the program's evidence-base, recruitment time, and resource access. Researchers should explore DPP implementation in real-world settings to determine overall and setting-specific best practices, promote intervention uptake, and reduce diabetes.

Weight Loss and Exercise Effects on Rate of Torque Development and Physical Function in Overweight Older Women.

Exercise training (EX) and weight loss (WL) improve lower extremity physical function (LEPF) in older overweight women; however, effects on rate of torque development (RTD) are unknown. This study aimed to determine the effects of WL + EX or WL alone on RTD, and relatedly LEPF, in overweight older women. Leg strength was assessed using isokinetic dynamometry, and RTD was calculated (RTD200 = RTD at 200 ms, RTDPeak = peak RTD, T2P = time to 1st peak). LEPF was determined via clinical functional tasks. Women (n = 44, 69.1 ± 3.6 years, 30.6 ± 4.3 kg/m2) completed a 6-month trial in EX + WL or WL groups with similar weight loss (-9.8 ± 4.2%, p > .95). EX + WL had greater improvements in (a) most LEPF tasks (p < .001) and (b) RTD200, compared with WL (36% vs. -16%, p = .031); no other RTD parameters differed. Changes in RTD parameters and LEPF were not related (all p > .05). RTD is responsive to EX but is not associated with LEPF in older women.

Differences in physical activity and perceived benefits and barriers to physical activity between LGBTQ + and non-LGBTQ + college students.

ObjectiveTo compare physical activity (PA) behaviors and perceived benefits and barriers among lesbian, gay, bisexual, transgender, and queer (LGBTQ+) and non-LGBTQ + college students. Participants: Participants were 406 college students. Methods: Surveys assessed PA behaviors and perceptions of PA among college students. Multivariate ANOVA assessed differences in PA behaviors and perceptions of PA. Results: LGBTQ + students (n = 71) engaged in 17% less aerobic PA and 42% less resistance training than their counterparts (n = 335; both p < .05). LGBTQ + students reported 6.5% lower total Exercise Benefits and Barriers Scale scores and 13.3% higher Barriers Scale scores (both p < .05). Conclusions: LGBTQ + college students are at higher risk of not meeting PA guidelines than non-LGBTQ + students. More perceived barriers and fewer perceived benefits to PA may contribute to this disparity. Identification of LGBTQ+-specific barriers to PA among college students is needed to inform programming to increase PA among this at-risk community.

Physical activity and perceived benefits, but not barriers, to exercise differ by sex and school year among college students.

Objective: To assess whether sex or school year influence physical activity and exercise (PA/EX) behaviors and perceived benefits and barriers of PA/EX among college students. Participants: Participants were 862 (78% female; 20.1 ± 1.4 years) college students. Methods: The International Physical Activity Questionnaire, Exercise Benefits and Barriers Scale, and resistance training (RT) questions were completed online. Results: Factorial ANOVA (sex x year) determined no significant interaction effects of sex and school year in behaviors or perceived benefits and barriers (all p > .05). Males reported higher levels of PA/EX and RT than females (p < .05) with no differences by school year (p = .34). Benefits Scale scores and some of its subscales were higher for males and first-year students compared to females and third- and fourth-year students (all p < .05). Conclusion: PA/EX promotion programs may need to be tailored differently based on sex and school year.

Sex-specific correlates of metabolic syndrome risk in college-aged young adults.

Objective: To identify the sex-specific prevalence of metabolic syndrome (MetS) risk factors and their physiological, psychosocial, and behavioral correlates in a college-aged population. Participants and methods: Cross-sectional assessment of MetS risk factors and potential correlates occurred in 379 first-year students (aged 18.34 ± 0.49 years, 67.3% female). Multivariable linear regression assessed the relationships between potential correlates and continuous MetS risk scores, derived from principal component analysis. Results: MetS risk factors were present in 58.4% of females and 68.5% of males, with 2.4% and 3.2% having defined MetS. In females, percent body fat (ß = 0.46, p < 0.001), stress (ß = 0.12, p = 0.031), % kcal from sugar (ß = 0.18, p = 0.001), and moderate-to-vigorous physical activity (ß=-0.12, p = 0.036) were associated with risk score. Whereas, correlates in males included percent body fat (ß = 0.54, p < 0.001), C-reactive protein (ß = 0.15, p = 0.045), and AUDIT alcohol consumption score (ß = 0.15, p = 0.033). Conclusion: The sex-specific prevalence of MetS risk factors and correlates suggest that primary prevention strategies on college campuses should also follow a sex-specific approach.

Exercise and Protein Effects on Strength and Function with Weight Loss in Older Women.

Obesity negatively affects lower extremity physical function (LEPF) in older adults. Exercise and a higher protein diet are both known to positively and independently affect body composition, muscle strength, and LEPF during weight loss; however, their potential interactive effects have not been well characterized in older women. PURPOSE: The aim of this study was to determine the relative efficacy of a higher protein diet with or without exercise to improve body composition, muscle strength, and LEPF in older inactive overweight/obese women after weight loss. METHODS: Postmenopausal women (body mass index = 31.1 ± 5.1 kg·m, 69.2 ± 3.6 yr) completed a 6-month weight loss program after randomization to three groups (n = 72 randomized; 15% dropout): 1) higher protein diet (PRO, ~30% energy from protein; n = 20), 2) PRO plus exercise (PRO + EX; n = 19), or 3) a conventional protein control diet plus EX (CON + EX, ~18% energy from protein; n = 22). EX was supervised, multicomponent (aerobic, muscle strengthening, balance, and flexibility), and three sessions per week. Body composition was measured via dual-energy x-ray absorptiometry, leg strength by isokinetic dynamometry, and LEPF via 6-min walk, 8-ft up and go, and 30-s chair stand tests. RESULTS: Changes in weight (-7.5 ± 4.1 kg; -9.2% ± 4.8%), fat mass, and leg lean mass did not differ among groups (all P > 0.50). Despite weight loss, muscle strength improved in the exercise groups (PRO + EX and CON + EX) but it declined in the PRO group (P = 0.008). For all LEPF measures, the PRO group had attenuated improvements compared with both PRO + EX and CON + EX (all P < 0.01). CONCLUSION: Exercise during weight loss is critical to preserve strength and enhance LEPF; however, a higher protein diet does not appear to influence body composition, muscle strength, or LEPF changes when combined with multicomponent exercise.

Sex-Specific Muscular Mediation of the Relationship Between Physical Activity and Cortical Bone in Young Adults.

Muscle mass is a commonly cited mediator of the relationship between physical activity (PA) and bone, representing the mechanical forces generated during PA. However, neuromuscular properties (eg, peak force) also account for unique portions of variance in skeletal outcomes. We used serial multiple mediation to explore the intermediary role of muscle mass and force in the relationships between cortical bone and moderate-to-vigorous intensity PA (MVPA). In a cross-sectional sample of young adults (n = 147, 19.7 ± 0.7 years old, 52.4% female) cortical diaphyseal bone was assessed via peripheral quantitative computed tomography at the mid-tibia. Peak isokinetic torque in knee extension was assessed via Biodex dynamometer. Thigh fat-free soft tissue (FFST) mass, assessed via dual-energy X-ray absorptiometry, represented the muscular aspect of tibial mechanical forces. Habitual MVPA was assessed objectively over 7 days using Actigraph GT3X+ accelerometers. Participants exceeded MVPA guidelines (89.14 ± 27.29 min/day), with males performing 44.5% more vigorous-intensity activity relative to females (p < 0.05). Males had greater knee extension torque and thigh FFST mass compared to females (55.3%, and 34.2%, respectively, all p < 0.05). In combined-sex models, controlling for tibia length and age, MVPA was associated with strength strain index (pSSI) through two indirect pathways: (i) thigh FFST mass (b = 1.11 ± 0.37; 95% CI, 0.47 to 1.93), and (i) thigh FFST mass and knee extensor torque in sequence (b = 0.30 ± 0.16; 95% CI, 0.09 to 0.73). However, in sex-specific models MVPA was associated with pSSI indirectly through its relationship with knee extensor torque in males (b = 0.78 ± 0.48; 95% CI, 0.04 to 2.02) and thigh FFST mass in females (b = 1.12 ± 0.50; 95% CI, 0.37 to 2.46). Bootstrapped CIs confirmed these mediation pathways. The relationship between MVPA and cortical structure appears to be mediated by muscle in young adults, with potential sex-differences in the muscular pathway. If confirmed, these findings may highlight novel avenues for the promotion of bone strength in young adults. © 2019 American Society for Bone and Mineral Research.

The relationship between animal and plant protein intake and overall diet quality in young adults.

BACKGROUND & AIMS: Overall diet quality is a key predictor of disease risk and mortality. Diets higher in animal protein have been associated with increased disease risk and all-cause mortality. However, the source of protein consumed will inevitably influence the intake of other macronutrients and micronutrients which can also play a role in the onset of disease. The aim of the present study was to assess the relationship between animal and plant protein intake and overall diet quality in young adult females and males. METHODS: Dietary intake was assessed via 3-day food log (n = 150; 53% females) and data were analyzed using the Nutrition Data Systems for Research (NDSR). RESULTS: Females and males consuming <70% of their protein from animal sources had higher scores on a modified Healthy Eating Index (HEI) compared those consuming >70% of their protein from animal sources. Males scored lower than females on the modified HEI regardless of protein source intake variation. CONCLUSIONS: Our findings suggest that overall diet quality differs with varying protein source consumption and eating <70% of protein from animal sources might lead to a better score on the HEI. Future research investigating protein source and disease risk should examine overall dietary quality as a potential effect modifier.

Mortality Risk Reductions for Replacing Sedentary Time With Physical Activities.

INTRODUCTION: Excess sitting is a risk factor for early mortality. This may be resulting, at least in part, from the displacement of physical activity with sedentary behaviors. The purpose of this observational study was to examine the mortality risk reductions associated with replacing 30minutes/day sitting for an equivalent duration of light or moderate to vigorous physical activity (MVPA). METHODS: Participants included 37,924 men and 54,617 women in the Cancer Prevention Study-II Nutrition Cohort, of which 14,415 men and 13,358 women died during follow-up (1999-2014). An isotemporal substitution approach to the Cox proportional hazards regression model was used to estimate adjusted hazard ratios and 95% CIs for mortality associated with the substitution of 30minutes/day self-reported sitting for light physical activity or MVPA. Analyses were conducted in 2018. RESULTS: Among the least active participants (≤17minutes/day MVPA), the replacement of 30minutes/day sitting with light physical activity was associated with a 14% mortality risk reduction (hazard ratio=0.86, 95% CI=0.81, 0.89) and replacement with MVPA was associated with a 45% mortality risk reduction (hazard ratio=0.55, 95% CI=0.47, 0.62). Similar associations were seen among moderately active participants (light physical activity replacement, hazard ratio=0.94, 95% CI=0.91, 0.97; MVPA replacement, hazard ratio=0.83, 95% CI=0.76, 0.88). However, for the most active (MVPA >38 minutes/day), substitution of sitting time with light physical activity or MVPA was not associated with a reduction in mortality risk (hazard ratio=1.00, 95% CI=0.97, 1.03, and hazard ratio=0.99, 95% CI=0.95, 1.02, respectively). CONCLUSIONS: These findings suggest that the replacement of modest amounts of sitting time with even light physical activity may have the potential to reduce the risk of premature death among less active adults.

Demographic-specific Validity of the Cancer Prevention Study-3 Sedentary Time Survey.

PURPOSE: This study examined the 1-yr test-retest reliability and criterion validity of sedentary time survey items in a subset of participants from a large, nationwide prospective cohort. METHODS: Participants included 423 women and 290 men age 31 to 72 yr in the Cancer Prevention Study-3. Reliability was assessed by computing Spearman correlation coefficients between responses from prestudy and poststudy surveys. Validity was assessed by comparing survey-estimated sedentary time with a latent variable representing true sedentary time estimated from the 7-d diaries, accelerometry, and surveys through the method of triads. Sensitivity analyses were restricted to 566 participants with an average of 14+ h of diary and accelerometer data per day for 7 d per quarter. RESULTS: Reliability estimates for total sitting time were moderate or strong across all demographic strata (Spearman ρ ≥ 0.6), with significant differences by race (P = 0.01). Reliability estimates were strongest for the TV-related sedentary time item (Spearman ρ, 0.74; 95% confidence interval, 0.70-0.77). The overall validity coefficient (VC) for survey-assessed total sedentary time was 0.62 (95% confidence interval, 0.55-0.69), although VC varied by age group and activity level (P < 0.05). However, VC were similar across groups (P < 0.05) when restricting to highly compliant participants in a sensitivity analysis. CONCLUSIONS: The Cancer Prevention Study-3 sedentary behavior questionnaire has acceptable reliability and validity for ranking or categorizing participants according to sedentary time. Acceptable reliability and validity estimates persist across various demographic subgroups.

Reduced body weight or increased muscle quality: Which is more important for improving physical function following exercise and weight loss in overweight and obese older women?

The purpose of this study was to examine the relative contributions of changes in muscle quality and body composition to changes in lower-extremity physical function (LEPF) following a 6-month exercise and weight loss intervention in overweight and obese older women. Thirty-eight overweight and obese (BMI = 30.0 ±â€¯4.4 kg/m2) older (age = 69.3 ±â€¯4.1 y) women completed 6 months of multicomponent exercise (cardiorespiratory, resistance, balance and flexibility training) and weight loss (hypocaloric diet that reduced energy intake by ~500 kcal/d). Body composition was measured via dual-energy X-ray absorptiometry and muscle quality (N-m/kg) was defined as maximal concentric isokinetic knee torque divided by upper-leg lean mass. The standardized scores of four objective measures of physical function were summed to yield a composite LEPF Z-score. At 6 months, there were significant reductions in body weight (-9.6 ±â€¯3.5%, p < 0.01), absolute fat mass (-6.8 ±â€¯2.4 kg, p < 0.01) and relative adiposity (-4.9 ±â€¯2.1%, p < 0.01). There were also improvements in both muscle quality (+1.6 ±â€¯1.8 N-m/kg, p < 0.01) and individual measures of LEPF (11-57%, p < 0.01). Multivariate linear regression indicated that increased muscle quality was the strongest independent predictor of an improvement in LEPF Z-score (standardized ß = 0.64, p < 0.01) and explained 34% of the variance. A reduction in body weight also predicted an improvement in LEPF, independent of the change in muscle quality. In conclusion, muscle quality can be increased in the presence of clinically meaningful weight loss, and is the primary determinant of improved physical function in overweight/obese older women.

Flexible Eating Behavior Predicts Greater Weight Loss Following a Diet and Exercise Intervention in Older Women.

Eating behaviors (cognitive restraint, flexible and rigid restraint, disinhibition, hunger) have been associated with obesity and weight loss success in middle-aged individuals, but little is known about these relationships in older adults. This study examined relationships between eating behaviors and weight loss in overweight/obese older women (n = 61; 69 ± 3.6 years; body mass index = 31.1 ± 5.0 kg/m2) completed a 6-month behavioral weight loss intervention. Baseline, postintervention, and change measures of eating behaviors (51-items Three-Factor Eating Questionnaire) were assessed for relationships with weight loss. In the final regression model, an increase in flexible restraint accompanied by a decrease in rigid restraint predicted greater weight loss (adjusted R2 = 0.21, Model F (4, 56) = 4.97, P < 0.01). No associations were found with disinhibition or hunger and degree of weight loss (all P > 0.05). Results suggest encouraging a flexible approach to eating behavior and discouraging rigid adherence to a diet may lead to better intentional weight loss for overweight and obese older women.

Predicting Diaphyseal Cortical Bone Status Using Measures of Muscle Force Capacity.

PURPOSE: Muscle cross-sectional area (MCSA) is often used as a surrogate for the forces applied to bones during physical activity. Although MCSA is a strong predictor of cortical bone status, its use makes assumptions about the relationship between muscle size and force that are inaccurate. Furthermore, to measure MCSA and other muscle force surrogates typically requires expensive and/or radiative laboratory equipment. Thus, this study aimed to determine whether clinical laboratory- and field-based methodologies for measuring muscular force capacity accounted for similar variance in diaphyseal cortical bone status as a commonly used muscular force surrogate, MCSA, at the midtibia in young men and women. METHODS: Healthy young adults (n = 142, 19.7 ± 0.7 yr old, 52.8% female) were assessed via peripheral quantitative computed tomography at the midtibia for cortical bone status and MCSA. Muscle force capacity was measured via Biodex dynamometer, Nottingham leg extensor power rig, and Vertec vertical jump. Regression analysis compared the independent variance predicted by each muscle force measure with that of MCSA, accounting for relevant confounders. RESULTS: MCSA, knee extension peak torque, and peak anaerobic power from vertical jump were independent predictors of select cortical structural outcomes (cortical thickness and area, periosteal and endosteal circumference, and estimated strength) accounting for up to 78.4% of the variance explained (all P < 0.05). However, cortical volumetric bone mineral density was unrelated to any measure or surrogate of muscle force capacity. CONCLUSIONS: MCSA is a strong independent predictor of cortical bone structure; however, both laboratory- and field-based measures of peak torque and/or peak anaerobic power are promising alternatives, explaining similar and sometimes greater variance than MCSA.

Interactive associations of physical activity, adiposity, and oral contraceptive use on C-reactive protein levels in young women.

Oral contraceptives (OCs) are the most frequently used type of birth control among young women. OC-users have higher C-reactive protein (CRP) values, an indicator of systemic inflammation, than do non-OC-users. In addition, adiposity (percent fat) is positively associated with CRP, and physical activity (PA) is inversely associated with CRP. The present study determined the interactive associations of PA, percent fat, and OC-use with CRP. Data were collected during 2012-2015 at the University of Georgia. Objective PA was measured via pedometers. Percent fat was measured via dual X-ray absorptiometry. The current OC-use was self-reported. High-sensitivity (hs) CRP was determined using venipuncture. Multivariate linear regression determined the interactive associations of percent fat, OC-use, and PA with hs-CRP. Participants (n = 247; mean age 18.9 ± 1.4 years, 60.7 percent white) accumulated a mean of 10,075.7 ± 3,593.4 steps/day. One-third of participants were categorized as overweight/obese by BMI (mean = 24.5 ± 4.8 kg/m2, mean percent fat = 35.2 ± 6.8). The current OC-use was reported by 26.2 percent of the sample (n = 61). A significant three-way interaction (ß = 0.01, p = .03) indicated that higher PA was associated with lower hs-CRP in non-OC-users with higher percent fat, but not among OC-users with higher percent fat. These results highlight the need to measure and account for the current OC-use in studies examining the relationship between PA and CRP.

Moderate, but not vigorous, intensity exercise training reduces C-reactive protein.

BACKGROUND: Sprint interval cycle training is a contemporary popular mode of training but its relative efficacy, under conditions of matched energy expenditure, to reduce risk factors for cardiometabolic disease is incompletely characterised, especially in young women. The purpose of this investigation was to determine the relative efficacy of six weeks of moderate-intensity cycling (MOD-C) and vigorous sprint-interval cycling (VIG-SIC) on lipid profile, insulin (INS) and insulin resistance using the homeostatic model assessment (HOMA-IR) and C-reactive protein (CRP) in inactive, overweight/obese (OW/OB) young women. METHODS: Participants (BMI ≥25 kg/m2, waist circumference ≥88 cm) were randomly assigned to MOD-C (20-30 min at 60-70% of heart rate reserve(HRR)) or VIG-SIC (5-7 repeated bouts 30-second maximal effort sprints, followed by four minutes of active recovery) supervised training three days/week for six weeks, with each group matched on energy expenditure. Adiposity (%Fat) was measured using dual x-ray absorptiometry. RESULTS: Forty-four participants (20.4 ± 1.6 years, 65.9% Caucasian, 29.8 ± 4.1 kg/m2) were included in the analysis. The improvement in CRP observed in the MOD-C group was larger than the VIG-C group (p = .034). Overall, high-density lipoprotein (HDL-C) and low-density lipoprotein (LDL-C) levels improved following training (p < .05); however, total cholesterol, triglyceride, INS and HOMA-IR did not improve (p > .05). CONCLUSION: These results indicate MOD-C training may be more effective in reducing CRP than VIG-SIC.