Influence of cardiorespiratory fitness and body composition on resting and post-exercise indices of vascular health in young adults.

Poor cardiorespiratory fitness may mediate vascular impairments at rest and following an acute bout of exercise in young healthy individuals. This study aimed to compare flow mediated dilation (FMD) and vascular augmentation index (AIx75) between young adults with low, moderate, and high levels of cardiorespiratory fitness before and after an acute bout of aerobic exercise. Forty-three participants (22 men; 21 women) between 18 and 29 years of age completed the study. Participants were classified into low, moderate, and high health-related cardiorespiratory fitness groups according to age- and sex-based relative maximal oxygen consumption (V˙O2 max) percentile rankings. FMD was performed using Doppler ultrasound and AIx75 was performed using pulse wave analysis at baseline and 60-min after a 30-min bout of treadmill running at 70% V˙O2 max. A significant interaction (p â€‹= â€‹0.047; ηp2 â€‹= â€‹0.142) was observed, with the moderate fitness group exhibiting a higher FMD post-exercise compared with baseline ([6.7% â€‹± â€‹3.1%] vs. [8.5% â€‹± â€‹2.8%], p â€‹= â€‹0.028; d â€‹= â€‹0.598). We found a significant main effect of group for AIx75 (p â€‹= â€‹0.023; ηp2 â€‹= â€‹0.168), with the high fitness group exhibiting lower AIx75 compared to low fitness group ([-10% â€‹± â€‹10%] vs. [2% â€‹± â€‹10%], respectively, p â€‹= â€‹0.019; g â€‹= â€‹1.07). This was eliminated after covarying for body fat percentage (p â€‹= â€‹0.489). Our findings suggest that resting FMD and AIx75 responses are not significantly influenced by cardiorespiratory fitness, but FMD recovery responses to exercise may be enhanced in individuals with moderate cardiorespiratory fitness levels.

The effects of an exercise intervention on executive function among overweight adults with obstructive sleep apnea.

PURPOSE: Obstructive sleep apnea (OSA) is associated with poorer executive function. This study examined the effects of a comprehensive exercise intervention on executive function in overweight adults with mild and moderate-to-severe OSA. METHODS: Participants aged between 30 and 65 years, with a body mass index (BMI) ranging from 27 to 42 kg/m2, participated in a 6-week exercise program. Standardized polysomnographic recording methods provided total Apnea-Hypopnea Index (AHI) and level of hypoxemia. Executive function was assessed using the NIH Toolbox Flanker Inhibitory Control Test. A submaximal treadmill exercise test evaluated cardiorespiratory fitness. Participants with baseline total AHI between 5 and 14.9 events/h were classified as mild OSA and participants with baseline total AHI 15 ≥ events/h were classified as moderate-to-severe OSA. RESULTS: Fifteen participants completed 18 exercise sessions. Significant differences between OSA categories at baseline were observed for sleep characteristics, but not for fitness or executive function. Wilcoxon Signed Rank Tests showed significant increases in median values for the Flanker Test in the moderate-to-severe category only, z = 2.429, p < .015, η2 = .737. CONCLUSION: Six weeks of exercise improved executive function in overweight individuals with moderate-to-severe OSA, but not in those with mild OSA.

High-intensity functional exercise does not cause persistent elevations in augmentation index in young men and women.

Elevations in central augmentation index (AIx) are predictive of cardiovascular disease. The objective of this study was to examine AIx immediately and 24 h following an acute bout of high-intensity functional training (HIFT) in apparently healthy young adults. A second aim compared the exercise-induced AIx recovery response between men and women. Thirty-two recreationally active younger adults (n = 16 men) were tested. Baseline central hemodynamic measures were assessed, followed by a single bout of bodyweight HIFT. The HIFT included 4 rounds of burpees, jump squats, split squats, and walking lunges. Assessments were repeated 5, 10, 15, and 24 h post-exercise. AIx was normalized to a heart rate of 75 bpm (AIx75). There was a significant main effect of time on AIx75 across all groups (P < 0.001) with AIx75 increasing at all acute time points compared with baseline and returning to resting values 24 h post-exercise. When examining sex differences after covarying for height and body fat percentage, the authors found no time × sex interaction (P = 0.62), or main effect for sex (P = 0.41), but the significant main effect of time remained (P < 0.001). The AIx75 response to HIFT follows a similar recovery pattern as previously studied modes of exercise with no residual effects 24 h later and no differences between men and women indicating no persistent cardiovascular strain in younger adults participating in this mode of exercise.

The Association Between Sleep and Musculoskeletal Injuries in Military Personnel: A Systematic Review.

INTRODUCTION: Musculoskeletal injuries (MSKIs) are a significant health problem in the military. Accordingly, identifying risk factors associated with MSKI to develop targeted strategies that attenuate injury risk remains a top priority within the military. Insufficient sleep has garnered increased attention as a potential risk factor for MSKI in both civilians and military personnel. Yet, there are no systematic evaluations of the potential association between sleep and MSKI in the military. The purpose of this review is to examine the relationship between sleep and injury in military personnel. MATERIALS AND METHODS: Literature searches were performed in multiple electronic databases using keywords relevant to sleep quantity and quality, MSKI, and military populations. Two investigators independently assessed the methodological quality of each study using the Newcastle-Ottawa Scale for cohort studies or an adapted form of this scale for cross-sectional studies. RESULTS: The search yielded 2402 total citations, with 8 studies (3 cohort and 5 cross-sectional) fitting the inclusion criteria. Overall, the systematic review found 5 of the 8 reviewed studies supporting an association between sleep (quality and duration) and MSKI in military personnel. Specifically, poor sleep was associated with increased injury incidence in 2 cohort and 3 cross-sectional studies. CONCLUSION: This is the first systematic review to evaluate the published literature on the association between sleep and MSKI risk in military populations. Although there is currently limited research on this topic, findings suggest that sleep is associated with MSKI and should be considered when designing strategies aimed at reducing MSKI risk in military personnel.

Positional Analysis of Body Composition Using Dual-Energy X-Ray Absorptiometry in National Collegiate Athletic Association Division I Football and Men's Lacrosse.

ABSTRACT: Zabriskie, HA, Dobrosielski, DA, Leppert, KM, Droege, AJ, Knuth, ND, and Lisman, PJ. Positional analysis of body composition using dual-energy X-ray absorptiometry in National Collegiate Athletic Association Division I football and men's lacrosse. J Strength Cond Res 36(6): 1699-1707, 2022-Despite the widespread use of dual-energy X-ray absorptiometry (DXA), few studies have examined differences in body composition between positions within sports and none have reported DXA-derived body composition reference values for men's lacrosse. The purpose of this study was to examine differences in measures of total and regional body composition and bone mineral density (BMD) using DXA across sport positions in a large cohort of National Collegiate Athletic Association Division I male lacrosse and football players. A total of 294 male athletes (football, n = 196; lacrosse, n = 98) underwent DXA. One-way analysis of variance or Kruskal-Wallis tests were used to examine whether body composition variables differed by sports position. In football, position was a significant determinant for every compositional variable in football athletes (all, p < 0.05; effect size range = 0.24-0.79). Offensive linemen had the highest total body fat percentage (30.1 ± 2.9%), followed by fullbacks (26.7 ± 3.3%) and defensive linemen (24.6 ± 5.7%); wide receivers had the lowest (14.5 ± 2.1%). For total body BMD, defensive linemen had the highest (1.70 ± 0.09 g·cm-3), followed by linebackers (1.67 ± 0.09 g·cm-3) and offensive linemen (1.65 ± 0.09 g·cm-3); kickers had the lowest (1.45 ± 0.11 g·cm-3) BMD. In lacrosse, no differences were found between positions for any total or regional body composition and BMD measure (all, p > 0.05). Our data confirm that total and regional measures of body composition and BMD vary across positions in football but not in men's lacrosse. Unlike football, similarities in body composition among lacrosse players may indicate that the uniformity of training demands or preferred player attributes in team selection outweigh the unique positional demands in gameplay.

How can exercise reduce cardiovascular disease risk? A primer for the clinician.

Despite advances in drug development and medical treatments, cardiovascular diseases (CVDs) remain a leading cause of mortality across the globe. Fortunately, CVD can be delayed by engaging in appropriate lifestyle behaviors. An abundance of epidemiological evidence supports a direct association between increased levels of physical activity or cardiovascular fitness and reduced premature CVD morbidity and mortality. These data have been used as the basis for many medical organizations to issue physical activity guidelines to citizens to improve physical activity participation and, ultimately, reduce the risk of CVDs and other chronic diseases. Despite these efforts, physical activity participation around the globe remains low. The medical professional is well suited to promote exercise as a preventative treatment for CVD, although promotion efforts may be less effective without a clear understanding of the mechanisms through which exercise confers cardioprotection. Thus, the purpose of this review is to highlight the cardioprotective effects of exercise training and to explore the underlying mechanistic pathways that might explain these benefits. The review will focus on those physiological pathways that are directly involved in atherosclerotic disease development. They include hypercholesterolemia, hypertension, chronic inflammation, and insulin resistance.

The Association Between Poor Sleep and the Incidence of Sport and Physical Training-Related Injuries in Adult Athletic Populations: A Systematic Review.

BACKGROUND: The importance of achieving an adequate amount of sleep to optimize health and athletic performance is well recognized. Yet, a systematic evidence compilation of the risk for sport-related injury in adult athletic populations due to poor sleep does not exist. OBJECTIVE: To examine the association between poor sleep and sport and physical training-related injuries in adult athletic populations. DATA SOURCES: Electronic databases were searched using keywords relevant to sleep quantity and quality, and musculoskeletal injury and sport-related concussion (SRC). ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Studies were included in this systematic review if they were comprised of adult athletic populations, reported measures of sleep quantity or quality, followed participants prospectively for injury, and reported an association between sleep and incidence of sport or physical training-related injury. STUDY APPRAISAL: The methodological quality of each study was assessed using the Newcastle-Ottawa Scale for Cohort Studies. RESULTS: From our review of 12 prospective cohort studies, we found limited evidence supporting an association between poor sleep and injury in adult athletic populations. Specifically, there is (a) insufficient evidence supporting the associations between poor sleep and increased risk of injury in specific groups of athletic adults, including professional or elite athletes, collegiate athletes, elite or collegiate dancers, and endurance sport athletes; and (b) limited evidence of an association between poor sleep and increased risk of SRC in collegiate athletes. CONCLUSIONS: The current evidence does not support poor sleep as an independent risk factor for increased risk of sport or physical training-related injuries in adult athletic populations. Given the methodological heterogeneity and limitations across previous studies, more prospective studies are required to determine the association between sleep and injury in this population.

The effects of exercise training on vascular function among overweight adults with obstructive sleep apnea.

Obstructive sleep apnea (OSA) is associated with increased cardiovascular morbidity due, in part, to impaired vascular function. Exercise confers cardioprotection by improving vascular health. Yet, whether OSA severity affects the vascular improvements conferred with exercise training is not known. Overweight (body mass index (BMI) >27 kg/m2) adults were evaluated for OSA and enrolled in a six-week exercise intervention. Baseline assessments of brachial artery flow-mediated dilation (BAFMD), central augmentation index (AIx) and pulse wave velocity (PWV) were repeated post training. Fifty-one participants (25 men; 26 women) completed the study. Despite improved aerobic capacity (p=0.0005) and total fat mass (p=0.0005), no change in vascular function was observed. Participants were divided into two severity groups according to their baseline total apnea-hypopnea index (AHI) as either 5 to 14.9 events•hr-1 (n= 21; Age=48 ± 7 yrs; BMI=33.7 ± 4.6kg•m-2) or 15 ≥events•hr-1 (n=30; Age=56 ± 13 yrs; BMI = 34.3 ± 4.2 kg•m-2). No effect of OSA group was observed for BAFMD (p=0.82), AIx (p=0.37) or PWV (p=0.44), suggesting that OSA severity does not influence the effect of exercise on vascular function. The vascular effects of extended exercise programs of greater intensity in overweight OSA patients should be examined.

Body Composition Values of NCAA Division 1 Female Athletes Derived From Dual-Energy X-Ray Absorptiometry.

ABSTRACT: Dobrosielski, DA, Leppert, KM, Knuth, ND, Wilder, JN, Kovacs, L, and Lisman, PJ. Body composition values of NCAA Division 1 female athletes derived from dual-energy x-ray absorptiometry. J Strength Cond Res 35(10): 2886-2893, 2021-This study generated descriptive data for regional and total body composition and bone mineral density (BMD) measures using dual-energy x-ray absorptiometry (DXA) across 12 NCAA Division 1 female competitive sports. Two hundred seventy-eight female collegiate athletes underwent DXA: basketball (BB; n = 28), cross country (CC = 11), field hockey (FH; n = 35), gymnastics (GYM; n = 23), lacrosse (LAX; n = 48), soccer (SOC; CC = 27), softball (SB; n = 24), swimming and diving (SW; n = 35), tennis (TN; n = 11), track and field ([TR-throw; n = 10]; [TR-run; n = 10]), and volleyball (VB; n = 16). Descriptive statistics for all body composition and BMD measures were calculated. Group mean differences in all regional and total body composition (all, p < 0.001; η2 range = 0.177-0.365) and BMD (all, p < 0.001; η2 range = 0.317-0.383) measures were observed between teams. The total BF% for gymnasts (23.5%) was lower than TN, FH, LAX, SB, and TR-throw (mean difference range: -4.6 to -12.9%, all p < 0.01); TR-throw had the highest total BF% (36.4%). Cross country had lower total BMD (1.17 g·cm-2) than FH, TR-throw, LAX, GYM, SOC, SB, VB, and BB (mean difference range: -0.12 to -0.26 g·cm-2, all p < 0.01); BB and TR-throw had the highest total BMD (1.40 and 1.43 g·cm-2, respectively). Our data confirm that regional and total body composition and BMD measures varied across female collegiate sports. These findings may assist sports medicine and strength and conditioning practitioners with identifying sport-specific goal values for BF% and BMD to optimize program design.

Examination of Sleep and Injury Among College Football Athletes.

Burke, TM, Lisman, PJ, Maguire, K, Skeiky, L, Choynowski, JJ, CapaldiII, VF, Wilder, JN, Brager, AJ, and Dobrosielski, DA. Examination of sleep and injury among college football athletes. J Strength Cond Res 34(3): 609-616, 2020-The purpose of this study was to characterize subjective sleep metrics in collegiate football players at the start of the season, determine the relationship between preseason subjective sleep measures and in-season objective sleep characteristics, and examine the association between subjective and objective sleep metrics and incidence of time-loss injury during the competitive season. Ninety-four Division I football players completed 5 validated sleep-related questionnaires to assess sleep quality, insomnia severity, daytime sleepiness, sleep apnea risk, and circadian preference before the start of the season. Clinical thresholds for sleep questionnaires were used to determine risk of sleep disorders. Continuous wrist actigraphy was collected throughout the season to generalize sleep behaviors. Time-loss injury incidence data were recorded and used for analysis. Results indicated that 67.4% (60 of 89) of athletes scored above clinical threshold in at least 1 questionnaire to indicate sleep disorder risk. At the start of the season, players subjectively reported an average sleep duration of 7:16 ± 1:18 hours:minutes, which was in contrast to the 6:04 ± 0:41 hours:minutes measured through actigraphy during the season. Logistic regression models adjusted for age and body mass index revealed no significant associations between injury and subjective (odds ratio [OR] = 1.00; 95% confidence interval [CI] = 0.99-1.01) and objective (OR = 1.01; 95% CI = 0.99-1.02) sleep duration or measures attained from sleep questionnaires (ORs ranged from 1.01 to 2.87). Sleep metrics (quantity and quality) were not associated with increased risk of injury in this cohort of collegiate football players.

Diet and exercise in the management of obstructive sleep apnoea and cardiovascular disease risk.

Obstructive sleep apnoea (OSA) is associated with increased cardiovascular disease (CVD) morbidity and mortality. It is accepted that OSA and obesity commonly coexist. The American Academy of Sleep Medicine recommends dietary-induced weight loss and exercise as lifestyle treatment options for OSA. However, most clinical trials upon which this recommendation is based have focused on establishing the effectiveness of calorie-restricted, often low-fat diets for improving OSA severity, whereas less attention has been given to the means through which weight loss is achieved (e.g. altered dietary quality) or whether diet or exercise mediates the associations between reduced weight, improved OSA severity and the CVD substrate. The current evidence suggests that the benefits of a low-carbohydrate or Mediterranean diet in overweight and obese individuals go beyond the recognised benefits of weight reduction. In addition, exercise has an independent protective effect on vascular health, which may counter the increased oxidative stress, inflammation and sympathetic activation that occur in OSA patients. This review aims to expand our understanding of the effects of diet and exercise on OSA and associated CVD complications, and sets the stage for continued research designed to explore optimal lifestyle strategies for reducing the CVD burden in OSA patients.

The Association between Regional Fat Distribution and Acute Mountain Sickness in Young Hikers.

Acute mountain sickness (AMS) can occur upon rapid ascent from low to high altitude. This study examined the association between central adiposity and the development of AMS in young adults during a high-altitude hike. Total and regional body fat were measured at sea level using dual-energy X-ray absorptiometry. Within 24 h of arriving in Cusco, Peru (3 400 meters) participants embarked on a 14-mile hike across the Andes Mountain range in southern Peru. Symptoms of AMS were assessed using the Lake Louise score at 24 h (3 400 meters), 29 h (4 100 meters), 34 h (3 800 meters) and 53 h (2 900 meters). 14 participants (mean age 21±2 years; women: 11, men: 3) completed the study. The number of participants exhibiting at least mild AMS increased from 6 (54%) at 3 400 meters to 9 (64%) at 3 800 meters. A higher AMS score at 4 100 meters was associated with greater android (r=0.72, p<0.01), trunk (r=0.73, p<0.01) and total body (r=0.71, p<0.01) fat, but not with total body fat % (r=0.39, p=0.16). Our findings suggest that central obesity, but not total body fat per se, may be an important factor in the development of AMS.

Estimating the Prevalence of Sleep-Disordered Breathing Among Collegiate Football Players.

BACKGROUND: Obstructive sleep apnea is a clinical disorder characterized by loud snoring, apneic episodes, and chronic sleep disruption. Collegiate football players exhibit several risk factors for OSA, including large neck circumference and high body mass index, although the prevalence of OSA in this cohort is unknown. METHODS: The STOP-BANG questionnaire was administered at random to members of a collegiate football team and used to stratify the players into high and low risk for sleep-disordered breathing (SDB). Those who completed the questionnaire were then evaluated for SDB during preseason camp using a single-channel (finger pulse oximetry) photoplethysmography-based device. SDB was defined as an apnea-hypopnea index of ≥5. RESULTS: Of 56 players who underwent overnight photoplethysmography monitoring, valid results were available for 51. Forty-eight percent of the players were high-risk (neck size = 44.6 ± 2.2 cm, body mass index = 33.0 ± 5.4) versus low-risk (neck size = 41.4 ± 2.8 cm, body mass index = 27.6 ± 3.6) (both P values <.001). An apnea-hypopnea index of ≥5 was found in 2 (8.3%, 95% CI 1.0-20.0%) high-risk and 2 (7.7, 95% CI 1.0-18.4%) low-risk players. Two offensive linemen, a linebacker, and a tight end accounted for the positive cases. CONCLUSIONS: Based on our sample, we estimate the prevalence of SDB among collegiate football players to be 8%, regardless of risk stratification. Given the strong link between SDB and cardiovascular disease, these data underscore the importance of screening and subsequent treatment of SDB in this highly conditioned yet potentially vulnerable group of athletes.

Associations between vasodilatory capacity, physical activity and sleep among younger and older adults.

INTRODUCTION: Exercise promotes cardiovascular health through its direct impact on the vascular endothelium. Conversely, poor sleep quality is associated with endothelial dysfunction, which may explain the increased cardiovascular disease amongst poor sleepers. Yet, the influence of physical activity and poor sleep quality on vascular health is not clear. PURPOSE: This study examined the relationships between forearm vasodilatory capacity, self-reported sleep quality and free-living, actigraphy-derived energy expenditure in a group of young and older community dwelling adults. METHODS: Venous occlusion plethysmography determined baseline and peak forearm blood flow following reactive hyperemia. Sleep quality was measured using the Pittsburgh Sleep Quality Index (PSQI). Measures of body composition were assessed using dual energy X-ray absorptiometry. RESULTS: A total of 104 (61 young; 43 old) participants completed the study. In general, younger participants were more active, as determined by steps per day and average daily energy expenditure, but reported poorer sleep quality. In the combined sample, those who reported moderate sleep disturbances (PSQI total score; 11-15) had significantly lower vasodilatory capacity (16.8 ± 7.6 ml/100 ml/min) compared to those who reported no sleep disturbance (PSQI total score; 0-5) (22.3 ± 7.2 ml/100 ml/min) or mild sleep disturbance (PSQI total score; 6-10) (22.3 ± 8.1 ml/100 ml/min) (p < 0.01). After adjustment for physical activity, total body fat and age, moderately poor sleep remained an independent predictor of forearm vasodilatory capacity. CONCLUSIONS: These findings suggest that any positive vascular benefits accrued through increased physical activity might be offset by the negative consequences of chronically disturbed sleep.

Lifestyle Intervention for Sleep Disturbances Among Overweight or Obese Individuals.

Little is known about the effect of different lifestyle interventions on sleep disturbances among sedentary obese or overweight persons. We randomized men and women aged 35-65 to 6 months of a weight loss diet (D); or D combined with supervised exercise training D + E. Measurements were self-reported sleep disturbances, the Profile of Mood States questionnaire, BMI, total abdominal subcutaneous and visceral fat by magnetic resonance imaging, and aerobic fitness expressed as VO2peak. The groups did not differ in changes for body weight, abdominal total fat, VO2peak, and sleep disturbances. The novel finding herein is that reduced abdominal subcutaneous fat and depressive symptoms, with either D or D + E were associated with less sleep disturbances.

Lean Mass and Fat Mass as Contributors to Physical Fitness in an Overweight and Obese African American Population.

OBJECTIVE: To determine the association of lean vs fat mass with fitness in healthy, overweight and obese African Americans from families with early-onset coronary disease. DESIGN: Cross-sectional study. SETTING: Baltimore, Maryland. PARTICIPANTS: 191 healthy, overweight, sedentary African Americans (69% women; aged 44.8 ± 11 years; body mass index 34 ± 5 kg/m2). MAIN OUTCOME MEASURES: Anthropometrics, smoking, blood pressure, lipids, c-reactive protein, and glucose were assessed with standard methods; body composition was determined by dual energy X-ray absorptiometry; cardiorespiratory fitness was expressed as VO(2peak) attained during a maximal treadmill test. RESULTS: In both men and women, greater lean mass was independently associated with higher VO(2peak) (P < .05) and explained > 21% of the variance in VO(2peak), adjusted for body mass index, fat mass, important covariables, and nonindependence of families. CONCLUSIONS: In this cross-sectional study, lean mass was the key determinant of cardiorespiratory fitness, independent of sex, age, and magnitude of obesity. These data provide a strong rationale for examining whether interventions that increase lean mass may also improve fitness, even among high-risk overweight and obese African Americans.

Effects of exercise and weight loss in older adults with obstructive sleep apnea.

PURPOSE: Obstructive sleep apnea (OSA) is prevalent among older individuals and is linked to increased cardiovascular disease morbidity. This study examined the change in OSA severity after exercise training and dietary-induced weight loss in older adults and the association of the changes in OSA severity, body composition, and aerobic capacity with arterial distensibility. METHODS: Obese adults (n = 25) with OSA, age 60 yr or older, were instructed to participate in supervised exercise (3 d·wk) and follow a calorie-restricted diet. Baseline assessments of OSA parameters, body weight and composition, aerobic capacity, and arterial distensibility were repeated at 12 wk. RESULTS: Nineteen participants completed the intervention. At 12 wk, there were reductions in body weight (-9%) and percentage of total body fat (-5%) and trunk fat (-8%) whereas aerobic capacity improved by 20% (all P < 0.01). The apnea-hypopnea index decreased by 10 events per hour (P < 0.01) and nocturnal SaO2 (mean SaO2) improved from 94.9% at baseline to 95.2% after intervention (P = 0.01). Arterial distensibility for the group was not different from that at baseline (P = 0.99), yet individual changes in distensibility were associated with the change in nocturnal desaturations (r = -0.49, P = 0.03) but not with the change in body weight, apnea-hypopnea index, or aerobic capacity. CONCLUSIONS: The severity of OSA was reduced after an exercise and weight loss program among older adults, suggesting that this lifestyle approach may be an effective first-line nonsurgical and nonpharmacological treatment for older patients with OSA.

The effect of intermittent pneumatic compression of legs on the levels of nitric oxide related species in blood and on arterial function in the arm.

BACKGROUND: Intermittent pneumatic compression (IPC) of legs exerts beneficial local vascular effects, possibly through local release of nitric oxide (NO). However, studies demonstrating systemic transport of nitrogen oxide species and release of NO prompt the question of whether IPC could also exert nonlocal effects. We tested whether IPC (1) affects systemic levels of nitrite, S-nitrosothiols and red blood cell (RBC) NO, and (2) exerts vasoactive effects in the brachial artery (BA), although this hypothesis-generating pilot study did not investigate cause and effect relationship between (1) and (2). METHODS: In 10 healthy subjects, ages 24-39 years, we measured plasma nitrite, plasma S-nitrosothiols and RBC-NO from venous blood samples drawn before and after IPC treatment. We also measured BA responses to 5 min of upper arm occlusion at rest and during 1 h of leg IPC. RESULTS: There was a significant decrease in plasma nitrite (112±26 nM to 90±15 nM, p=0.0008) and RBC-NO (129±72 nM to 102±41 nM, p=0.02). Plasma S-nitrosothiols were unchanged (5.79±4.81 nM to 6.27±5.79 nM, p=0.3). BA occlusion-mediated constriction (OMC) was significantly attenuated with IPC treatment (-43±13% to -33±12%, p=0.003). High-flow mediated BA dilation was unchanged (13.3±9.4% to 11.5±7.2%, p=0.2). CONCLUSION: Plasma nitrite, RBC-NO, and BA OMC decreased with leg IPC. We hypothesize that this decrease in circulatory pool of plasma nitrite and RBC-NO may result from the transfer of their NO-bioactivity from blood to the hypoxic arm tissue, to be stored and released under hypoxic stress and oppose OMC. Future studies should investigate whether IPC-induced decreases in brachial OMC are caused by the changes in systemic NO activity, and whether leg IPC could benefit distant arterial function in systemic cardiovascular disease.

Effect of exercise on abdominal fat loss in men and women with and without type 2 diabetes.

OBJECTIVE: To examine the effect of exercise on abdominal adipose tissue in adults with and without type 2 diabetes mellitus (T2DM). DESIGN: Post hoc analysis of two randomised controlled trials. SETTING: Outpatient secondary prevention programme in Baltimore, Maryland, USA. PARTICIPANTS: 97 men and women with prehypertension, stage 1 or medically controlled hypertension. 49% of the sample was also diagnosed with T2DM. INTERVENTION: All participants completed a 26-week (6.5 months) supervised aerobic and resistance exercise programme following American College of Sports Medicine guidelines. PRIMARY AND SECONDARY OUTCOME MEASURES: The main outcomes in this post hoc analysis were total abdominal adipose tissue (TAT), subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) measured by MRI. Secondary outcomes were to determine whether the magnitude of abdominal fat change differed by diabetes status in men and women and to identify the predictors of change in abdominal fat distribution with exercise. RESULTS: Overall, participants (mean age 61±6 years; 45% women) significantly improved peak oxygen uptake by 15% (p<0.01) and reduced weight by 2% (p<0.01). No change in SAT was observed after training. The reduction in VAT following exercise was attenuated in participants with T2DM (-3%) compared with participants who were non-T2DM (-18%, p<0.001 for the difference in change). The magnitude of VAT loss was associated with a decrease in body weight (r=0.50, p<0.001). After adjustment for weight change using regression analysis, diabetes status remained an independent predictor of the change in VAT. CONCLUSIONS: Although participants with and without T2DM attained an exercise training effect as evidenced by increased fitness, VAT was unchanged in T2DM compared to those without T2DM, suggesting that these individuals may be resistant to this important benefit of exercise. The strategies for reducing cardiovascular disease risk in T2DM may be most effective when they include a weight loss component. CLINICAL TRIALS REGISTRATION: Clinicaltrials.gov Registry NCT00212303.