The Impact of a Lifestyle Intervention on Postpartum Cardiometabolic Risk Factors Among Hispanic Women With Abnormal Glucose Tolerance During Pregnancy: Secondary Analysis of a Randomized Trial.

BACKGROUND: Women with abnormal glucose tolerance during pregnancy are at risk for cardiovascular disease (CVD), with higher rates among Hispanics. However, studies on the impact of lifestyle interventions on postpartum CVD profiles are sparse. METHODS: This is a secondary analysis of a controlled trial among a subsample of Hispanic women with abnormal glucose tolerance participating in Estudió PARTO (Project Aiming to Reduce Type twO diabetes; mean age = 28.2 y, SD: 5.8) who were randomized to a culturally modified Lifestyle intervention (n = 45) or a comparison Health and Wellness intervention (n = 55). Primary endpoints were biomarkers of cardiovascular risk (lipids, C-reactive protein, fetuin-A, and albumin-to-creatinine ratio) and insulin resistance (fasting insulin, glucose, HbA1c, homeostasis model assessment, leptin, tumor necrosis factor-alpha, and adiponectin) measured at baseline (6-wk postpartum) and 6 and 12 months. RESULTS: In intent-to-treat analyses, there were no significant differences in changes in biomarkers of CVD risk or insulin resistance over the postpartum year. In prespecified sensitivity analyses, women adherent with the Lifestyle Intervention had more favorable improvements in insulin (intervention effect = -4.87, SE: 1.93, P = .01) and HOMA-IR (intervention effect = -1.15, SE: 0.53, P = .03) compared with the Health and Wellness arm. In pooled analyses, regardless of intervention arm, women with higher postpartum sports/exercise had greater increase in HDL-cholesterol (intervention effect = 6.99, SE: 1.72, P = .0001). CONCLUSIONS: In this randomized controlled trial among Hispanic women with abnormal glucose tolerance, we did not observe a significant effect on postpartum biomarkers of CVD risk or insulin resistance. Women adherent to the intervention had more favorable changes in insulin and HOMA-IR.

Change in Views of Aging, Physical Activity, and Physical Health Over 8 Weeks: Results From a Randomized Study.

The AgingPLUS program targets motivational barriers, including negative views of aging, as mechanisms to increase adult physical activity. A pilot study was conducted to test the efficacy of this new program against a generic successful aging program. Fifty-six participants were randomly assigned to the AgingPLUS group, and 60 participants were assigned to the active control group. Repeated-measures multivariate analyses of variance assessed changes in views of aging, physical activity, blood pressure, and hand-grip strength from pretest (Week 0) to delayed posttest (Week 8). The Condition × Occasion interactions were nonsignificant; however, significant main effects for condition and occasion were found. Follow-up tests showed that views of aging were more positive, and physical activity had significantly increased at Week 8 for all participants. In addition, in the treatment group, elevated blood pressure had significantly decreased and hand-grip strength had significantly increased at Week 8. Despite the nonsignificant multivariate findings, the main effect findings provided partial support for the efficacy of the AgingPLUS program.

Evaluation of Two Training Programs Designed to Enhance Performance on the Army Combat Fitness Test Among ROTC Cadets.

INTRODUCTION: Physical fitness is foundational to the U.S. Army as a component of combat readiness, and accurate assessment of readiness is imperative for mission success and soldiers' health and safety. To this end, the Army has developed the Army Combat Fitness Test (ACFT), which more accurately assesses these abilities and may aid development of a more combat-ready force. Reserve Officer Training Corps (ROTC) programs nationwide are often challenged by limited structured training time, as well as access to equipment and training space. Development and/or adaptation of a training program that addresses these limitations would benefit ROTC programs nationally. Therefore, the purpose of this study was to compare a standard military fitness training program to High-Intensity Functional Training (HIFT) in ROTC cadets. We hypothesized that a HIFT program would be more effective than the standard military program developed by the DoD on both ACFT performance and assessment of common Warrior Tasks and Battle Drills (WTBDs). MATERIALS AND METHODS: This study was approved by the Institutional Review Board at Colorado State University (CSU). Participants were recruited from CSU's Army ROTC program. Before and upon completion of the training intervention, participants completed a battery of testing, conducted over three visits. The first visit consisted of body composition assessment and measurement of aerobic capacity (VO2max). Visit 2 was the ACFT, and Visit 3 was a "benchmark test" to assess WTBD performance. Participants then completed 10 weeks of group training. Once weekly, participants completed the Daily Analysis of Life Demands for Athletes (DALDA) survey to monitor the risk of overtraining. STATISTICAL ANALYSIS: Responses to training and survey responses were examined using two-way analysis of variance (time × group) with repeated measures. Baseline characteristics were compared using Student's t-test to assess pre-intervention differences between groups. Pearson product correlations were used to test relationships between ACFT performance, body composition, and performance on the benchmark assessment. The significance level alpha was set at P < .05. RESULTS: Twenty-five men and 10 women competed the study (n = 35). Mean age was 19.8 ± 1.3 years, range 18-23. There were no significant changes in absolute or relative VO2max within or between groups. We found no difference in body mass, but did find a small but statistically significant favorable change in body composition, with no difference between groups. Overall ACFT scores and scores in five of the six events increased significantly across both groups, with no significant differences between groups. For the benchmark test, there was no significant difference between pre- and post-intervention benchmark scores, time to completion, 1,600-m ruck time, or accuracy. DALDA survey results indicate no apparent risk for overtraining. CONCLUSION: Three 60-minute sessions per week of moderate-high-intensity training elicited improvements in ACFT scores, with no statistically significant differences between training programs. For this population of ROTC cadets, implementing a structured training program with expert oversight appears to be effective. Based on the successes and unanticipated challenges encountered in this study, training programs that emphasize intensity, train a wide variety of movements, maximize adherence, and are adaptable to a variety of situations are likely to be successful at improving ACFT scores.

Comprehensive assessment of cardiovascular structure and function and disease risk in middle-aged ultra-endurance athletes.

BACKGROUND AND AIMS: Recent studies suggest that long-term endurance training may be damaging to the heart, thus increasing cardiovascular disease (CVD) risk. However, studies utilizing cardiac imaging are conflicting and lack measures of central and peripheral vascular structure and function, which are also independently predictive of CVD events. METHODS: We performed a comprehensive assessment of cardiovascular structure and function in long-term (≥ 10 years) ultra-endurance athletes (ATH, 14 M/11 F, 50 ± 1 y) and physically active controls (CON, 9 M/9 F, 49 ± 2 y). RESULTS: As expected, left ventricular mass and end-diastolic volume (echocardiography) were greater in ATH vs CON, whereas there was no difference in cardiac function at rest. Coronary artery calcium scores (computed tomography) were not statistically different between groups. There was no evidence of myocardial fibrosis (contrast magnetic resonance imaging) in any subject. Aortic stiffness (carotid-femoral pulse wave velocity) was lower in ATH vs CON (6.2 ± 0.2 vs 6.9 ± 0.2 m/s, p < 0.05), whereas carotid intima-media thickness (ultrasound) was not different between groups. Peripheral vascular endothelial function (flow-mediated vasodilation of the brachial artery) and microvascular function (peak blood velocity) in response to 5 min of forearm ischemia were not different between groups. Furthermore, there was no difference in 10-year coronary heart disease risk (ATH; 2.3 ± 0.5 vs CON; 1.6 ± 0.2%, p > 0.05). CONCLUSIONS: Our data indicate that middle-aged ultra-endurance ATH do not have marked signs of widespread cardiovascular dysfunction or elevated CHD risk compared to CON meeting physical activity guidelines.

Stress and Anxiety are Associated with Lower Gestational Weight Gain in Hispanic Women.

OBJECTIVE: Prior studies indicate that inadequate and excessive gestational weight gain (GWG) are associated with poor maternal and infant outcomes, and that stress and anxiety may contribute to GWG. However, these studies often failed to use validated measures of stress and anxiety, measured only total GWG, and were limited to largely non-Hispanic White populations. We explored the association between stress and anxiety and GWG. METHODS: We used data from 1,308 participants in Proyecto Buena Salud, a prospective cohort of predominantly Puerto Rican women 18-40 years of age (2006-2012). We measured stress with the Perceived Stress Scale and anxiety with the State-Trait Anxiety Scale, and abstracted GWG from medical records. RESULTS: The average GWG was 31.0 ± 16.1 pounds. More than one-half of participants (51.8%) exceeded Institute of Medicine guidelines for GWG. After adjusting for age and pre-pregnancy body mass index, women in the highest quartiles of stress and anxiety in early pregnancy had approximately 4 lbs lower GWG (ß = -3.89; SE = 1.54; p = .012 and ß = -4.37; SE = 1.54; p = .005, respectively) as compared with those in the lowest quartiles. Similarly, women in the highest quartiles of mid/late pregnancy stress and anxiety had lower GWG (ß = -3.84 lbs; SE = 1.39; p = .006, and ß = -3.51 lbs; SE = 1.38; p = .011, respectively) and a lower rate of GWG in the second and third trimesters (ß = -0.117 lbs/week; SE = 0.044; p = .008 and ß = -0.116 lbs/week; SE = 0.043; p = .007, respectively), compared with those in the lowest quartiles. CONCLUSIONS: High stress and anxiety were associated with lower GWG. Interventions to decrease stress and anxiety during pregnancy should include counseling on maintaining healthy GWG.

Using Ecological Momentary Assessment to Examine the Effects of Duty Status on Acute Stress and Tiredness in Firefighters: A Pilot Study.

OBJECTIVE: Characterize firefighters' acute stress and tiredness by duty status (ie, "off night/day," "on night/day"). METHODS: Thirty nine career firefighters completed three, eight-day smartphone-based ecological momentary assessment periods with seven surveys per day assessing stress and tiredness. Mixed-effects location scale models examined duty status effects on stress and tiredness. RESULTS: Firefighters' lowest stress and tiredness levels were when off-duty (ß = 16.27 and ß = 24.71, respectively) and their highest levels were when on-duty (ß = 24.47 and ß = 32.18, respectively). Within-subject effects of duty status accounted for a larger proportion of variability in stress and tiredness for all duty types, except for stress when "on-duty night/off-duty day." CONCLUSIONS: Firefighters had more similar stress and tiredness outcomes when they were on-duty and less similar outcomes when off-duty. This could be due to firefighters having more similar experiences when they are on- versus off-duty.

The impact of a randomized controlled trial of a lifestyle intervention on postpartum physical activity among at-risk hispanic women: Estudio PARTO.

AIMS: To assess the impact of a culturally modified, motivationally targeted, individually-tailored intervention on postpartum physical activity (PA) and PA self-efficacy among Hispanic women. METHODS: Estudio PARTO was a randomized controlled trial conducted in Western Massachusetts from 2013-17. Hispanic women who screened positive for gestational diabetes mellitus were randomized to a Lifestyle Intervention (LI, n = 100) or to a comparison Health and Wellness (HW, n = 104) group during late pregnancy. Exercise goals in LI were to meet American College of Obstetrician & Gynecologists guidelines for postpartum PA. The Pregnancy Physical Activity Questionnaire (PPAQ) and the Self-Efficacy for Physical Activity Questionnaire were administered at 6 weeks, 6 months, and 1 year postpartum. RESULTS: Compared to baseline levels, both groups had significant increases in moderate-to-vigorous PA at 6 months and one year postpartum (i.e., LI: mean change = 30.9 MET-hrs/wk, p = 0.05; HW: 27.6 MET-hrs/wk, p = 0.01), with only LI group experiencing significant increases in vigorous PA (mean change = 1.3 MET-hrs/wk, p = 0.03). Based on an intent-to-treat analysis using mixed effects models, we observed no differences in pattern of change in PA intensity and type over time between intervention groups (all p > 0.10). However, there was the suggestion of a greater decrease in sedentary activity in the LI group compared to the HW group (ß = -3.56, p = 0.09). CONCLUSIONS: In this randomized trial among high-risk Hispanic women, both groups benefitted from participation in a postpartum intervention.

Metrics of Diabetes Risk Are Only Minimally Improved by Exercise Training in Postmenopausal Breast Cancer Survivors.

CONTEXT: Insulin resistance is a risk factor for breast cancer recurrence. How exercise training changes fasting and postglucose insulin resistance in breast cancer survivors is unknown. OBJECTIVE: To evaluate exercise-induced changes in postglucose ingestion insulin concentrations, insulin resistance, and their associations with cancer-relevant biomarkers in breast cancer survivors. SETTING: The University of Massachusetts Kinesiology Department. PARTICIPANTS: 15 postmenopausal breast cancer survivors not meeting the physical activity guidelines (150 min/week of exercise). INTERVENTION: A supervised 12-week aerobic exercise program (60 min/day, 3-4 days/week). MAIN OUTCOME MEASURES: Postglucose ingestion insulin was determined by peak insulin and area under the insulin curve (iAUC) during a 5-sample oral glucose tolerance test. Insulin sensitivity was estimated from the Matsuda composite insulin sensitivity index (C-ISI). Changes in fitness and body composition were determined from submaximal VO2peak and dual energy X-ray absorptiometry. RESULTS: Participants averaged 156.8 ± 16.6 min/week of supervised exercise. Estimated VO2peak significantly increased (+2.8 ± 1.4 mL/kg/min, P < .05) and body weight significantly decreased (-1.1 ± 0.8 kg, P < .05) following the intervention. There were no differences in fasting insulin, iAUC, C-ISI, or peak insulin following the intervention. Insulin was only significantly lower 120 min following glucose consumption (68.8 ± 34.5 vs 56.2 ± 31.9 uU/mL, P < .05), and there was a significant interaction with past/present aromatase inhibitor (AI) use for peak insulin (-11.99 non-AI vs +13.91 AI uU/mL) and iAUC (-24.03 non-AI vs +32.73 AI uU/mL). CONCLUSIONS: Exercise training had limited overall benefits on insulin concentrations following glucose ingestion in breast cancer survivors but was strongly influenced by AI use.

Accounting for the Nutritional Context to Correctly Interpret Results from Studies of Exercise and Sedentary Behavior.

There is a wealth of research lauding the benefits of exercise to oppose cardiometabolic disease such as diabetes, CVD and hypertension. However, in the great majority of these studies, the nutritional context (energy balance, deficit, or surplus) has been ignored, despite its profound effect on responses to both exercise and inactivity. Even a minor energy deficit or surplus can strongly modulate the magnitude and duration of the metabolic responses to an intervention; therefore, failure to account for this important confounding variable obscures clear interpretation of the results from studies of exercise or inactivity. The aim of this review is to highlight key lessons from studies examining the interaction between exercise and sedentary behavior, energy status, and glucose and insulin regulation. In addition to identifying notable problems, we suggest a few potential solutions.

The combination of exercise training and sodium-glucose cotransporter-2 inhibition improves glucose tolerance and exercise capacity in a rodent model of type 2 diabetes.

PURPOSE: Exercise is recommended in addition to pharmacotherapies for the management of type 2 diabetes, but metformin and exercise training may have non-additive or even inhibitory effects on exercise-induced improvements in glycemic control and exercise capacity. The objectives of this report were to determine if co-treatment with a sodium-glucose cotransporter-2 inhibitor and exercise could (1) further improve glycemic control when compared to either monotherapy and (2) not worsen exercise capacity when compared to exercise alone. METHODS: A rodent model of type 2 diabetes (30 mg/kg streptozotocin and high-fat feeding in male Sprague-Dawley rats) was used to assess 12 weeks of co-treatment with a sodium-glucose cotransporter 2 inhibitor (SGLT2i) and exercise (EX; treadmill running) on glycemic control and exercise capacity. Animals were randomized to the following conditions (n = 7-10/group): vehicle (0.5% methyl cellulose) sedentary (VEH SED), VEH EX, canagliflozin (3 mg kg-1 d-1) SED (SGLT2i SED), or SGLT2i EX. RESULTS: Both EX and SGLT2i independently improved indices of glycemic control. The combination of SGLT2i and EX further improved glucose tolerance (glucose area under the curve 1109 ±â€¯51 vs 1427 ±â€¯82 mmol/ L 120 min-1 for SGLT2i EX vs. SGLT2i SED, respectively; p < 0.05) and insulin responses (insulin area under the curve 24,524 ±â€¯4126 vs. 41,208 ±â€¯2714 pmol L-1 120 min-1 for SGLT2i EX vs. VEH EX, respectively; p < 0.05) during an oral glucose tolerance test. Only the combination of SGLT2i EX lowered body weight compared to VEH SED (p < 0.01). SGLT2i caused several metabolic adaptations including increased ketone production and a greater reliance on fat as a source of energy during normal cage activity. Interestingly, animals that were given the SGLT2i and underwent exercise training (SGLT2i EX) had better submaximal exercise capacity than EX alone, as indicated by distance run prior to fatigue (882 ±â€¯183 vs.433 ±â€¯33 m for SGLT2i EX and VEH EX, respectively; p < 0.01), and this was accompanied by a greater reliance on fat as an energy source during exercise (p < 0.01). CONCLUSIONS: If these findings with the combination of SGLT2i and exercise translate to humans, they will have important clinical health implications.

Elevated insulin levels following 7 days of increased sedentary time are due to lower hepatic extraction and not higher insulin secretion.

Higher insulin following sedentary behavior may be due to increased insulin secretion (IS), decreased hepatic insulin extraction (HIE), or a combination of both. Ten healthy adults completed glucose tolerance tests following 7 days of normal activity and 7 days of increased sitting. There were no differences in IS; however, HIE at 120 min after ingestion (85.4% ± 7.2% vs. 74.6% ± 6.6%, p < 0.05) and the area under the curve (73.6% ± 9.4% vs. 67.5% ± 11.3%, p < 0.05) were reduced following 7 days of increased sedentary time.

Managing free-living hyperglycemia with exercise or interrupted sitting in type 2 diabetes.

Breaking up sitting with light physical activity (PA) is effective in reducing hyperglycemia in the laboratory. Whether the same effects are observed in the free-living environment remains unknown. We evaluated how daily and postprandial glycemia is impacted by 20, 40, or 60 min of activity performed as either breaks from sitting after each meal (BR) or as one continuous walk after breakfast (WALK). Thirty individuals with type 2 diabetes completed three experimental conditions [BR, WALK, and control (CON)] in a randomized crossover design. Conditions were performed in a free-living environment with strict dietary control over 7 days. Participants increased PA in BR and WALK by 20, 40, or 60 min ( n = 10 in each group) and maintained habitual levels of PA during CON. A continuous glucose monitor (iPro2) and activPAL activity monitor were worn to quantify glycemic control and PA. Using linear mixed models with repeated measures, we 1) compared postprandial glucose (PPG) across conditions and 2) assessed the relationship between activity volume and glucose responses. Whereas WALK tended to shorten the daily duration of hyperglycemia compared with CON ( P = 0.0875), BR was not different from CON. BR and WALK significantly attenuated the breakfast PPG versus CON ( P ≤ 0.05), but lunch and dinner PPG were unaffected by BR and WALK. In conclusion, continuous walking was more effective than breaks from sitting in lowering daily hyperglycemia for the group, but both conditions lowered breakfast PPG. In contrast to tightly controlled laboratory studies, breaks from sitting did not lower hyperglycemia in the free-living environment. NEW & NOTEWORTHY Our "ecolabical" approach is new and noteworthy. This approach combines the external validity of the free-living environment (ecological) with the control of key confounding variables in the laboratory and allows for highly translatable findings by minimizing confounding variables. We found that both postmeal continuous walking and short breaks from sitting similarly attenuated the postprandial glucose (PPG) response to breakfast. Unlike previous laboratory studies, neither condition (walk after breakfast or postmeal breaks) significantly impacted PPG at lunch or dinner.

The Health Behaviors of Ethnically Diverse Women at Increased Risk of Gestational Diabetes: The Behaviors Affecting Baby and You (B.A.B.Y.) Study.

Objectives Cigarette smoking, low physical activity, and sedentary behavior are modifiable risk factors for adverse pregnancy outcomes. However, only one study has evaluated predictors of these health risk behaviors among women at high risk for gestational diabetes mellitus (GDM). Therefore, our goal was to examine predictors of smoking, low physical activity, and sedentary behavior during pregnancy in an ethnically diverse high risk cohort. Methods This cross-sectional analysis utilized baseline data from the Behaviors Affecting Baby and You (B.A.B.Y.) study conducted among prenatal care patients at high risk for GDM (personal history of GDM or family history of diabetes and body mass index [BMI] ≥ 25 kg/m2). Smoking was assessed using questions from the Pregnancy Risk Assessment Monitoring System questionnaire and sedentary behavior (top vs. lower quartiles) and moderate/vigorous physical activity (bottom vs. upper quartile) via the Pregnancy Physical Activity Questionnaire. Results Participants (n = 400) enrolled at a mean of 12.4 (SD 3.6) weeks gestation. A total of 150 (44.1%) engaged in one, 37 (10.9%) in two, and 4 (1.2%) in three risk behaviors. Lower household income and not having children at home were each associated with a 2-6 fold increased odds of smoking, high sedentary behavior, and engaging in at least one risk behavior. Being married, Hispanic or of younger age was associated with a 2-6 fold reduced odds of smoking. BMI and personal history of GDM were not associated with risk behaviors. Conclusions for Practice Findings help characterize high risk groups and inform prenatal interventions targeting these health risk behaviors.

The Effect of an Exercise Intervention on Gestational Weight Gain: The Behaviors Affecting Baby and You (B.A.B.Y.) Study: A Randomized Controlled Trial.

PURPOSE: To examine the effect of a prenatal exercise intervention on gestational weight gain (GWG) and to update meta-analyses. DESIGN: Randomized controlled trial and meta-analysis. SETTING: Obstetrical practices in a Western Massachusetts hospital. PATIENTS: We analyzed 241 ethnically diverse pregnant participants at high risk for gestational diabetes in the Behaviors Affecting Baby and You (B.A.B.Y.) study. A total of 118 participants were randomized to an exercise intervention group and 123 to a comparison health and wellness intervention group. INTERVENTION: A 12-week individually tailored, motivationally matched program designed to increase the compliance with guidelines for exercise during pregnancy (30 min/day). MEASURES: The GWG and compliance with 2009 Institute of Medicine (IOM) guidelines for GWG abstracted from medical records. ANALYSIS: Unadjusted logistic regression, intent-to-treat. Results were added to the existing meta-analyses using a random effects model. RESULTS: Women randomized to the exercise group had a lower mean GWG than the comparison group (-0.97 kg, P value = .39) and were less likely to exceed IOM guidelines (odds ratio = 0.69, 95% confidence interval [CI] 0.34-1.40), but results were not statistically significant. Meta-analyses yielded a -0.63 kg (95% CI -1.17 to -0.08, P = .02) reduction in GWG and a 20% reduction in odds of exceeding IOM guidelines (95% CI 0.73 to 0.89) for the exercise intervention. CONCLUSION: Findings from this randomized trial among ethnically diverse women contribute to the results of meta-analyses supporting exercise as a means of attenuating GWG.

Prepregnancy Body Mass Index, Gestational Weight Gain, and Odds of Cesarean Delivery in Hispanic Women.

OBJECTIVE: This study aimed to evaluate the association between prepregnancy body mass index (BMI), gestational weight gain (GWG), and cesarean delivery in Hispanics. METHODS: We examined these associations among 1,215 participants in Proyecto Buena Salud, a prospective cohort of Hispanic women studied from 2006 to 2011. Prepregnancy BMI, GWG, and the mode of delivery were abstracted from medical records. RESULTS: A quarter of the participants entered pregnancy with obesity, 23% delivered via cesarean, and 52% exceeded the Institute of Medicine guidelines for GWG. After adjusting for age, women with obesity had 2.03 times the odds of cesarean delivery compared with women with normal BMI (95% confidence interval [CI]: 1.46-2.82); findings remained significant after adjusting for GWG. Women with excessive total GWG had 1.49 times the odds of cesarean delivery (95% CI: 1.06-2.10) compared with women who gained within guidelines. An excessive rate of third trimester GWG (standard deviation [SD] change in GWG per week) increased the odds of cesarean delivery (odds ratio = 1.66; 95% CI: 1.05-2.62), while an excessive rate of first and third trimester GWG was not associated with increased odds. CONCLUSIONS: Obesity prior to pregnancy was associated with increased odds of cesarean delivery among Hispanics. Excessive GWG across pregnancy and an excessive rate of third trimester GWG were also associated with increased odds.

Exercise training and metformin, but not exercise training alone, decreases insulin production and increases insulin clearance in adults with prediabetes.

Adding metformin to exercise does not augment the effect of training alone to boost whole body insulin sensitivity and lower circulating insulin concentrations. Although lower insulin concentrations (lower supply) following lifestyle and/or pharmacological interventions are primarily attributed to reductions in insulin secretion that match increases in peripheral insulin sensitivity (lower demand), it is unclear whether exercise and/or metformin exert direct effects on insulin production, extraction, or clearance. Thirty-six middle-aged, obese, sedentary adults with prediabetes were randomized to placebo (P), metformin (M), exercise and placebo (E+P), or exercise and metformin (E+M) for 12 wk. Fasting plasma proinsulin (an indicator of insulin production), C-peptide, insulin, and glucose were collected before and after the intervention. Peripheral insulin sensitivity (euglycemic clamp), hepatic insulin extraction, insulin clearance, body weight, and cardiorespiratory fitness were also measured. Fasting proinsulin was unchanged following P (19.4 ± 10.1 vs. 22.6 ± 15.0 pmol/l), E+P (15.1 ± 7.4 vs. 15.5 ± 7.4 pmol/l), or M (24.8 ± 18.9 vs. 16.7 ± 20.3 pmol/l) but was significantly reduced after E+M (18.6 ± 11.9 vs. 13.9 ± 6.7 pmol/l; P = 0.04). Insulin clearance was significantly greater following M (384.6 ± 19.4 vs. 477.4 ± 49.9; P = 0.03) and E+M (400.1 ± 32.0 vs. 482.9 ± 33.9; P = 0.02) but was unchanged in P or E+P. In this study, metformin combined with exercise training reduced circulating proinsulin, and both groups taking metformin increased insulin clearance. This suggests that adding metformin to exercise may augment or attenuate training effects depending on the outcome or organ system being assessed.NEW & NOTEWORTHY Exercise is increasingly viewed as medication, creating a need to understand its interactions with other common medications. Research suggests metformin, a widely prescribed diabetes medication, may diminish the benefits of exercise when used in combination. In this study, however, metformin combined with exercise training, but not exercise alone, lowered proinsulin concentrations and increased insulin clearance in adults with prediabetes. This may directly influence personalized prescriptions of lifestyle and/or pharmacology to reduce diabetes risk.

Using a novel data resource to explore heart rate during mountain and road running.

Online, accessible performance and heart rate data from running competitions are posted publicly or semi-publicly to social media. We tested the efficacy of one such data resource- Strava- as a tool in exercise physiology investigations by exploring heart rate differences in mountain racing and road racing running events. Heart rate and GPS pace data were gathered from Strava activities posted by 111 males aged 21-49, from two mountain races (Mt. Washington Road Race and Pike's Peak Ascent) and two road race distances (half marathon and marathon). Variables of interest included race finish time, average heart rate, time to complete the first half (by distance) of the race, time to complete the second half, average heart rate for both the first and second half, estimated maximal heart rate, and competitiveness (finish time as percentage of winning time). Mountain runners on average showed no change in heart rate in the second versus first half of the event, while road racers at the half marathon and marathon distances showed increased second-half heart rate. Mountain runners slowed considerably more in the second half than road runners. Heart rate increases in road races were likely reflective of cardiac drift. Altitude and other demands specific to mountain racing may explain why this was not observed in mountain races. Strava presents enormous untapped opportunity for exercise physiology research, enabling initial inquiry into physiological questions that may then be followed by targeted laboratory studies.

Gestational Weight Gain, Body Mass Index, and Risk of Hypertensive Disorders of Pregnancy in a Predominantly Puerto Rican Population.

Objectives To prospectively evaluate the association between gestational weight gain (GWG), prepregnancy body mass index (BMI), and hypertensive disorders of pregnancy using the revised Institute of Medicine (IOM) Guidelines. Methods We examined these associations among 1359 participants in Proyecto Buena Salud, a prospective cohort study conducted from 2006 to 2011 among women from the Caribbean Islands. Information on prepregnancy BMI, GWG, and incident diagnoses of hypertension in pregnancy were based on medical record abstraction. Results Four percent (n = 54) of women were diagnosed with hypertension in pregnancy, including 2.6 % (n = 36) with preeclampsia. As compared to women who gained within IOM GWG guidelines (22.8 %), those who gained above guidelines (52.5 %) had an odds ratio of 3.82 for hypertensive disorders (95 % CI 1.46-10.00; ptrend = 0.003) and an odds ratio of 2.94 for preeclampsia (95 % CI 1.00-8.71, ptrend = 0.03) after adjusting for important risk factors. Each one standard deviation (0.45 lbs/week) increase in rate of GWG was associated with a 1.74 odds of total hypertensive disorders (95 % CI 1.34-2.27) and 1.86 odds of preeclampsia (95 % CI 1.37-2.52). Conclusions for Practice Findings from this prospective study suggest that excessive GWG is associated with hypertension in pregnancy and could be a potentially modifiable risk factor in this high-risk ethnic group.

Impact of Metformin on Exercise-Induced Metabolic Adaptations to Lower Type 2 Diabetes Risk.

Combining metformin with exercise has been proposed to improve glucose homeostasis. However, we primarily discuss evidence suggesting that metformin and other pharmacological agents/dietary supplements (e.g., statins, resveratol, or antioxidants) may in fact oppose exercise-induced benefits on insulin sensitivity and cardiometabolic health. We explore the novel hypothesis that attenuation of oxidative stress from exercise by these exogenous compounds blunts metabolic adaptation.