Virtual Reality Adaptive Training for Personalized Stress Inoculation.

OBJECTIVE: To evaluate a personalized adaptive training program designed for stress prevention using graduated stress exposure. BACKGROUND: Astronauts in the high-risk space mission environment are prone to performance-impairing stress responses, making preemptive stress inoculation essential for their training. METHODS: This work developed an adaptive virtual reality-based system that adjusts environmental stressors based on real-time stress indicators to optimize training stress levels. Sixty-five healthy subjects underwent task training in one of three groups: skill-only (no stressors), fixed-graduated (prescheduled stressor changes), and adaptive. Psychological (subjective stress, task engagement, distress, worry, anxiety, and workload) and physiological (heart rate, heart rate variability, blood pressure, and electrodermal activity) responses were measured. RESULTS: The adaptive condition showed a significant decrease in heart rate and a decreasing trend in heart rate variability ratio, with no changes in the other training conditions. Distress showed a decreasing trend for the graduated and adaptive conditions. Task engagement showed a significant increase for adaptive and a significant decrease for the graduated condition. All training conditions showed a significant decrease in worry and anxiety and a significant increase in the other heart rate variability metrics. CONCLUSION: Although all training conditions mitigated some stress, the preponderance of trial effects for the adaptive condition supports that it is more successful at decreasing stress. APPLICATION: The integration of real-time personalized stress exposure within a VR-based training program not only prepares individuals for high-stress situations by preemptively mitigating stress but also customizes stressor levels to the crew member's current state, potentially enhancing resilience to future stressors.

How Does Rescuer Fitness Affect the Quality of Prolonged Cardiopulmonary Resuscitation?

Objective: High quality cardiopulmonary resuscitation (CPR) is crucial for patients experiencing cardiac arrest. CPR quality declines within the first few minutes of CPR performance. Being more fit is associated with higher CPR quality, yet the fitness parameters needed remain uncertain. It is also unknown how CPR quality is affected during a protocol of realistic CPR when rescuers switch compressors every two minutes, as recommended by the American Heart Association (AHA), and extended duration, as might be encountered with an out-of-hospital cardiac arrest. The purpose of the present study is to determine the extent to which different measures of physical fitness predict high quality CPR performance when rescuers follow current CPR guidelines. Methods: Subjects underwent a fitness assessment evaluating lower back muscular endurance, abdominal muscular endurance, upper body muscular strength, and upper body anaerobic power. At least 48 hours later, subjects returned to the laboratory for CPR testing. CPR quality was determined by compression rate (>100/minute), compression depth (>2 inches, or 50 mm), and adequate (full) chest recoil between compressions, based on American Heart Association guidelines. A CPR Quality Score, designed to represent cardiac output, was calculated as the product of compression rate and depth. Results: Thirty-three of 42 subjects were able to achieve a CPR Quality Score greater than 5000, the minimum needed to meet AHA recommendations. Higher anaerobic power and bench press scores were predictive of both high CPR Quality Scores (R2=0.47) and compression depth (R2=0.47). Sex (female) was predictive of better chest compression recoil percentages (R2=0.15). Conclusion: Most rescuers can maintain high quality CPR if given two minute breaks between cycles. Rescuers with high anaerobic fitness and muscular strength may be able to provide higher quality CPR.

Delayed window of improvements in skin microvascular function following a single bout of remote ischaemic preconditioning.

NEW FINDINGS: What is the central question of this study? Animal infarct studies indicate a delayed window of cardiac protection after remote ischaemic preconditioning (RIPC); however, the presence and duration of this delayed effect have not been examined in human microvasculature in vivo. What is the main finding and its importance? Cutaneous vasodilatation induced by local heating or ACh was increased significantly 24 and 48 h after a single bout of RIPC, respectively. Neither response persisted beyond ∼48 h. Sodium nitroprusside-induced cutaneous vasodilatation was not altered. These findings reveal a delayed increase in microvascular endothelial function after a single bout of RIPC. ABSTRACT: Remote ischaemic preconditioning (RIPC) induces protective effects from ischaemia-reperfusion injury. In the myocardium and conduit vasculature, a single bout of RIPC confers delayed protection that begins 24 h afterwards and lasts for 2-3 days. However, the extent and the time line in which a single bout of RIPC affects the human microvasculature are unclear. We hypothesized that a single bout of RIPC results in a delayed increase in skin microvascular function. Sixteen healthy participants (age, 23 ± 4 years; seven males, nine females; MAP, 82 ± 7 mmHg) were recruited to measure cutaneous microvascular function immediately before a single bout of RIPC and 24, 48 and 72 h and 1 week after the bout. The RIPC consisted of four repetitions of 5 min of arm blood flow occlusion interspersed by 5 min reperfusion. Skin blood flow responses to local heating (local temperature of 42°C), ACh and sodium nitroprusside were measured by laser speckle contrast imaging and expressed as the cutaneous vascular conductance (CVC; in perfusion units per millimetre of mercury). Vasodilatation in response to local heating was increased 24 and 48 h after RIPC (ΔCVC, 1.05 ± 0.07 vs. 1.18 ± 0.07 and 1.24 ± 0.08 PU mmHg-1 , pre- vs. 24 and 48 h post-RIPC; P < 0.05). Acetylcholine-induced cutaneous vasodilatation increased significantly 48 h after RIPC (ΔCVC, 0.71 ± 0.07 vs. 0.93 ± 0.12 PU mmHg-1 , pre- vs. 48 h post-RIPC; P < 0.05) and returned to baseline thereafter. Sodium nitroprusside-mediated vasodilatation did not change. Thus, a single bout of RIPC elicited a delayed response in the microvasculature, resulting in an improvement in the endothelium-dependent cutaneous vasodilatory response that peaked ∼48 h post-RIPC.

Improved endothelial-dependent and endothelial-independent skin vasodilator responses following remote ischemic preconditioning.

One week of daily remote ischemic preconditioning (RIPC) improves cutaneous vasodilatory (VD) function. However, the underlying mechanisms and the number of sessions needed to optimize this adaptive response remain unclear. We hypothesized that the responses to localized heating of the skin will be greater after 2 wk as opposed to 1 wk of RIPC. Furthermore, 2 wk of repeated RIPC will augment cutaneous VD responses to thermal and pharmacological stimuli. In methods, twenty-four participants (24 ± 2 yr; 13 men, 11 women) performed repeated RIPC (7 daily sessions over 1 wk, n = 11; 12 sessions over 2 wk, n = 13), consisting of four repetitions of 5 min of arm blood flow occlusion separated by 5 min reperfusion. Laser speckle contrast imaging was used to measure skin blood flow responses, in perfusion units (PU), to local heating (Tloc = 42°C), acetylcholine (ACh), and sodium nitroprusside (SNP) before and after repeated RIPC. Data were expressed as cutaneous vascular conductance (CVC, in PU/mmHg). In results, the VD response to local heating increased after RIPC (∆CVC from baseline; 1 wk: 0.94 ± 0.11 to 1.19 ± 0.15, 2 wk: 1.18 ± 0.07 to 1.33 ± 0.10 PU/mmHg; P < 0.05) but the ∆CVC did not differ between weeks. SNP-induced VD increased after 2 wk of RIPC (∆CVC; 0.34 ± 0.07 to 0.63 ± 0.11 PU/mmHg; P < 0.05), but ACh-induced VD did not. In conclusion, repeated RIPC improves local heating- and SNP-mediated cutaneous VD. When compared with 1 wk of RIPC, 2 wk of RIPC does not induce further improvements in cutaneous VD function.NEW & NOTEWORTHY Repeated RIPC increases the cutaneous vasodilatory response to local heating and to sodium nitroprusside but not to acetylcholine. Thus, endothelial-independent and local heating-mediated cutaneous vasodilation are improved following RIPC. However, 2 wk of RIPC sessions are not more effective than 1 wk of RIPC sessions in enhancing local heating-mediated cutaneous vasodilation.

Seven consecutive days of remote ischaemic preconditioning improves cutaneous vasodilatory capacity in young adults.

KEY POINTS: Remote ischaemic preconditioning (RIPC), induced by brief bouts of ischaemia followed by reperfusion, confers vascular adaptations that protect against subsequent bouts of ischaemia; however, the effect of RIPC repeated over several days on the human microcirculation is unknown. Using skin as a model, microvascular function was assessed at a control and a NO-inhibited area of skin before 1 day after and 1 week after administering seven consecutive days of repeated RIPC on the contralateral arm. Maximal vasodilatation was increased by ∼20-50% following 7 days of repeated RIPC, and this response remained elevated 1 week after stopping RIPC; however, NO-mediated vasodilatation was not affected by the RIPC stimulus. These data indicate that repeated RIPC augments maximal vasodilatation, but the underlying mechanism for this improvement is largely independent of NO. This finding suggests a role for other endothelium-derived mediators and/or for endothelium-independent adaptations with repeated RIPC. ABSTRACT: Remote ischaemic preconditioning (RIPC), induced by intermittent periods of ischaemia followed by reperfusion, confers cardiovascular protection from subsequent ischaemic bouts. RIPC increases conduit and resistance vessel function; however, the effect of RIPC on the microvasculature remains unclear. Using human skin as a microvascular model, we hypothesized that cutaneous vasodilatory (VD) function elicited by localized heating would be increased following repeated RIPC. Ten participants (23 ± 1 years, 6 males, 4 females) performed RIPC for seven consecutive days. Each daily RIPC session consisted of 4 repetitions of 5 min of arm blood flow occlusion interspersed by 5 min reperfusion. Before, 1 day after and 1 week after the 7 days of RIPC, two microdialysis fibres were placed in ventral forearm skin for continuous infusion of Ringer solution or 20 mM l-NAME. Red blood cell flux was measured by laser Doppler flowmetry at each fibre site during local heating (Tloc  = 39°C) and during maximal VD elicited by heating (Tloc  = 43°C) and 28 mM sodium nitroprusside infusion. Data were normalized to cutaneous vascular conductance (flux/mmHg). Seven days of RIPC did not alter the nitric oxide (NO) contribution to the VD response to local heating (P > 0.05). However, the maximal VD was augmented (Pre: 2.5 ± 0.2, Post: 3.8 ± 0.5 flux/mmHg; P < 0.05) and remained elevated 1 week post RIPC (3.3 ± 0.4 flux/mmHg; P < 0.05). Repeated RIPC improves maximal VD but does not affect NO-mediated VD in the cutaneous microvasculature. This finding suggests that other factors may explain the vasodilatory adaptations that occur following repeated RIPC.

Gerontological education: Course and experiential differences across academic colleges.

A knowledgeable workforce is key to meeting the demands of an aging population that is expected to nearly triple by 2030 and their attitudes influence propensity to seek aging-related careers. Postsecondary education offers an opportunity to increase aging-related knowledge and facilitates intergenerational experiential-learning opportunities; however, research is lacking regarding attitudes toward aging and experiences among an academically diverse sample. To address this gap, the aims of this study were to (1) examine differences in students' attitudes toward older adults by academic college, (2) assess differences in aging-related coursework and course experiences by academic college, and (3) explore key factors associated with students' attitudes toward older adults. Online survey methodology was used with a sample of 816 undergraduate students from a single university who represented all academic colleges offering undergraduate degrees. Significant differences among students' attitudes toward older adults by academic college were noted: those enrolled in the College of Human Sciences reported better stereotype, separation, and affective attitudes. Furthermore, factors associated with students' aging-related attitudes were sex, affiliation with academic college, perception of "old," contact frequency, and desire to learn aging-related content. The authors suggest interdisciplinary and disciplinary-specific educational recommendations to improve students' attitudes toward older adults.

A Community-Based Exergaming Physical Activity Program Improves Readiness-to-Change and Self-Efficacy Among Rural-Residing Older Adults.

Rural-residing older adults (OA) are not meeting physical activity (PA) recommendations, such that identifying methods of increasing PA among OA remains an ongoing challenge. This study evaluated the effect of a community-based exergaming program on PA readiness-to-change and self-efficacy among rural-residing OA (n = 265). There was a significant (p = .008) increase in readiness-to-change classification from PRE to POST. Significant increases in self-efficacy, or confidence in their ability to be physically active for a prescribed period of time, were detected for 35 (p = .011) and 40 min (p = .035) of continuous PA. PA self-efficacy change for 35 min of continuous PA (F [3,137] = 3.973, p = .010) and 40 min of continuous PA (F [3,137) = 2.893, p = .038) were influenced by the interaction between PRE self-reported health and PRE PA readiness-to-change levels. Results suggest that an exergaming-themed PA intervention is effective at increasing PA participation and self-efficacy for PA among rural-residing OA.

Community-based exergaming program increases physical activity and perceived wellness in older adults.

Exergaming may be an effective strategy to increase physical activity participation among rural older adults. This pilot project examined the effects of a 24-wk exergaming and wellness program (8 wk onsite exergaming, 16-wk wellness newsletter intervention) on physical activity participation and subjective health in 46 rural older adults. Sociodemographic data and self-reported physical activity were analyzed using descriptive statistics and Cochran's Q, respectively. Qualitative data were reviewed, categorized on the basis of theme, and tabulated for frequency. Increased physical activity and perceived health were the most reported perceived positive changes. Significant increases in physical activity participation were maintained among participants who were physically inactive at baseline. Best-liked features were physical activity and socialization. Findings suggest that this pilot exergaming and wellness program is effective in increasing physical activity in sedentary rural older adults, increasing socialization, and increasing subjective physical health among rural older adults.

Psychological correlates of physical activity among adults living in rural and urban settings.

Middle-aged and older adults living in rural settings have been consistently less likely to report regular physical activity (PA) than those living in urban settings. While past literature has identified sociodemographic and environmental correlates of PA that may contribute to these differences, consideration of psychological correlates has been limited. A total of 95 rural and urban adults ≥50 years old provided self-reported sociodemographic information, PA level, and psychological correlates of PA including measures assessing motivation, self-efficacy, social support, and attitudes related to PA. The average participant age was 68.6 years, and most were female (62.1%) and married (70.5%). While PA level did not differ significantly between the rural and urban groups, different psychological correlates contributed significantly to separate rural and urban linear regression models considering PA status. Among rural adults, more positive attitudes toward PA, and greater PA self-efficacy and social support were associated with greater amounts of PA while for urban adults, no psychological correlates were significantly associated with PA. Psychosocial factors may be key considerations in developing more effective PA interventions in middle-aged and older adults living in rural areas.

Assessing the Mental Model State of Emergency Responders in the Context of Radiological Dispersal Device (RDD) Incidents: A Multi-state Study.

ABSTRACT: Hazardous Materials (HAZMAT) Technicians' notions of mental model, or cognitive representations of their understanding and beliefs regarding Radiological Dispersal Devices (RDDs) incidents, have not been previously explored. A prior study developed an Expected Mental Model State (EMMS) framework specific to RDD incident response for HAZMAT technicians. The work herein presents the development of a derivative of this framework, the EMMS Diagnostic Matrix, to evaluate the actual Mental Model State (MMS) of HAZMAT technicians in the context of RDD incidents. The EMMS Diagnostic Matrix was administered via a survey and simulation activity in four U.S. states representing the Northeast, West, South, and Midwest regions. Data were collected and coded using grounded theory methodology. Reflexive thematic analysis was employed to identify themes across related areas where the notions of mental model for the HAZMAT technician responders' actual MMS differed from the EMMS. The analysis of the collected data revealed four significant themes representing incomplete notions of the mental model spanning various EMMS conceptual domains: Overestimation of Radiation Dose and Health Effects, indicating misunderstandings about the health impacts of radiation exposure, Acute Radiation Syndrome (ARS), particularly in the lower range of radiation doses; Overreliance on Responder Protection [personal protective equipment (PPE)/self-contained breathing apparatus (SCBA)], highlighting gaps in understanding radiation principles and radioactive material dispersal properties from a radiological dispersal device; Misunderstanding Radiation Detection and Units, signifying confusion about radiation units and differentiation between dose rate and accumulated dose; and Incomplete Understanding of Radiation Characteristics and Dispersal Properties, outlining a limited grasp of inhalation risks from radiation and the dispersal traits of a radiological dispersal device. The interconnectedness of these technical misunderstandings can guide the development of a strategic plan to evaluate and modify existing training, aiming at these specific themes to improve the efficiency of HAZMAT technicians in emergency situations and to identify areas for further research.

Law Enforcement Officers Have an Increased Prevalence of Subclinical Cardiovascular Disease That Is Not Explained by Traditional Risk Factors.

OBJECTIVES: The aim of the study is to determine if law enforcement officers develop subclinical atherosclerotic cardiovascular disease (ASCVD) earlier than nonofficers and, if so, the extent to which conventional risk factors explain this difference. Methods: Estimated pulse wave velocity (ePWV) was the marker of subclinical ASCVD. EPWV, ASCVD risk factors, metabolic syndrome (MetS), and 10-year risk for ASCVD were compared among 408 law enforcement officers and a civilian cohort. Results: EPWV, 10-year ASCVD risk, and MetS prevalence increased significantly with age. All but the officers age 55 and older had higher ePWV cohort than the civilian cohort ( P < 0.001). Ten-year ASCVD risk explained the most variability of ePWV ( R2 = 0.49, P < 0.001). Conclusions: Officers develop subclinical ASCVD earlier than nonofficers. Conventional ASCVD risk factors only explain about half of this increase. Occupational factors may play a role in contributing to this increased ASCVD risk.

Perceptions of technology among older adults.

Changes and advancements in technology have the potential to benefit older adults by promoting independence and increasing the ability to age in place. However, older adults are less likely to adopt new technology unless they see benefits to themselves. This study assessed the perceptions of 30 older adults in the Midwest concerning technology via three separate focus groups (i.e., independent apartment complex, a rural community, exercise program participants), which addressed a need in the literature (i.e., inclusion of oldest-old and rural individuals). The focus group questions included items such as what technology older adults currently used, desired improvements in technology, and the greatest challenges participants were facing or would face in the future. Overall, older adults were enthusiastic about learning new forms of technology that could help them maintain their independence and quality of life. Five themes emerged from all three focus groups: (a) Frustrations, Limitations, and Usability Concerns; (b) Transportation; (c) Help and Assistance; (d) Self-Monitoring; and (e) Gaming. The themes have important implications for future technology developed for older adults; in particular, older adults were willing and eager to adopt new technology when usefulness and usability outweighed feelings of inadequacy.

The effect of soy protein beverages on serum cell adhesion molecule concentrations in prehypertensive/stage 1 hypertensive individuals.

OBJECTIVE: Prehypertensive and hypertensive individuals are at increased risk of atherosclerotic cardiovascular disease (CVD), in part because hypertension contributes to endothelial dysfunction and increased cell adhesion molecule expression. Soy protein and isoflavones may favorably alter CVD risk factors, and hence the aim of this study was to determine whether intake of cow's milk compared with soy beverage prepared from whole soy bean (WSB) or soy protein isolate (SPI) would lower soluble cell adhesion molecule concentrations as a means of decreasing CVD risk. METHODS: We enrolled healthy prehypertensive/stage 1 hypertensive men (n = 60; 18-63 years) and premenopausal women (n = 8; 20-48 years). Participants were randomized to 1 of 3 groups for 8 weeks: cow's milk (600 mL/d), SPI beverage (840 mL/d; 30.1 mg total isoflavones/d), or WSB beverage (840 mL/d; 91.4 mg total isoflavones/d). We measured soluble vascular cell adhesion molecule-1 (VCAM-1), intercellular cell adhesion molecule-1 (ICAM-1), and endothelial-leukocyte adhesion molecule-1 (E-selectin) concentrations at baseline and week 8. RESULTS: Soluble CAM concentrations were not altered by treatment and did not differ between prehypertensive and hypertensive participants. However, analysis of variance indicated a treatment × gender interaction (gender effect) for ICAM-1 (p = 0.0037) but not for E-selectin (p = 0.067) or VCAM-1 (p = 0.16). Men had higher concentrations of ICAM-1 and E-selectin, respectively, at baseline (p = 0.0071, p = 0.049) and week 8 (p = 0.0054, p = 0.038) than women did. CONCLUSION: Neither intake of cow's milk nor soy beverage for 8 weeks altered soluble CAM concentrations in prehypertensive/stage 1 hypertensive individuals, suggesting that neither type of beverage diminished atherosclerotic CVD risk in mildly hypertensive individuals by way of improving circulating CAM concentrations.

The dose-response relationship of balance training in physically active older adults.

A 6-wk group balance-training program was conducted with physically active older adults (based on American College of Sports Medicine requirements) to investigate the effect of dose-related static and dynamic balance-specific training. All participants, age 60-87 yr, continued their regular exercise program while adding balance training in 1 of 3 doses: three 20-min sessions/wk (n = 20), one 20-min session/wk (n = 21), or no balance training (n = 19). Static balance (single-leg-stance, tandem), dynamic balance (alternate stepping, limits of stability), and balance confidence (ABC) were assessed pre- and posttraining. Significant interactions were observed for time in single-leg stance, excursion in limits of stability, and balance confidence, with the greatest increase observed in the group that completed 3 training sessions/wk. The results demonstrate a dose-response relationship indicating that those who are already physically active can improve balance performance with the addition of balance-specific training.

Delayed Cutaneous Microvascular Responses With Non-consecutive 3 Days of Remote Ischemic Preconditioning.

The optimal frequency and duration of remote ischemic preconditioning (RIPC) that augments microvascular function is unknown. A single bout of RIPC increases cutaneous endothelial function for ∼48 h, whereas 1 week of daily RIPC bouts improves more sustained endothelium-independent function. We hypothesized that 3 days of RIPC separated by rest days (3QOD RIPC) would result in sustained increases in both endothelium-dependent and endothelium-independent functions. Cutaneous microvascular function was assessed in 13 healthy young participants (aged 20.5 ± 3.9 years; 5 males, 8 females) before 3QOD and then 24, 48, and 72 h and a week after 3QOD. RIPC consisted of four repetitions of 5 min of blood flow occlusion separated by 5 min of reperfusion. Skin blood flow responses to local heating (T loc = 42°C), acetylcholine (Ach), and sodium nitroprusside (SNP) were measured using laser speckle contrast imaging and expressed as cutaneous vascular conductance (CVC = PU⋅mmHg-1). Local heating-mediated vasodilation was increased 72 h after 3QOD and the increased responsivity persisted a week later (1.08 ± 0.24 vs. 1.34 ± 0.46, 1.21 ± 0.36 PU⋅mmHg-1; ΔCVC, pre-RIPC vs. 72 h, a week after 3QOD; P = 0.054). Ach-induced cutaneous vasodilation increased a week after 3QOD (0.73 ± 0.41 vs. 0.95 ± 0.49 PU⋅mmHg-1; ΔCVC, pre-RIPC vs. a week after 3QOD; P < 0.05). SNP-induced cutaneous vasodilation increased 24 h after 3QOD (0.47 ± 0.28 vs. 0.63 ± 0.35 PU⋅mmHg-1; ΔCVC, pre-RIPC vs. 24 h; P < 0.05), but this change did not persist thereafter. Thus, 3QOD induced sustained improvement in endothelium-dependent vasodilation but was not sufficient to sustain increases in endothelium-independent vasodilation.

Stress and cardiovascular disease risk in female law enforcement officers.

PURPOSE: To assess the levels of stress and the prevalence of cardiovascular disease (CVD) risk factors in female law enforcement officers (LEOs). METHODS: Self-reported data including job-related stress and CVD risk factors were obtained from 65 female LEOs. Stress scores were compared with 429 males LEOs and CVD risk factors were compared with 1,213 demographically similar female respondents to the CDC BRFSS survey. All subjects resided in Iowa. RESULTS: Female LEOs had more stress (perceived stress, p < 0.01), more job-related stress (job strain, vital exhaustion and effort-reward imbalance, p < 0.01 for all), but similar social support (social provision scale, p = 0.412) than male LEOs. Female LEOs had a significantly higher prevalence of hypercholesterolemia than the general Iowa female population (46.2 vs. 29.3%, p < 0.01). There was a trend towards a higher prevalence of diabetes in female LEOs (9.2 vs. 4.5%, p = 0.084). The most commonly cited contributor to their perceived CVD risk was stress (77%). Female LEOs who felt that being either a LEO (67.7%) or a female LEO (41.5%) contributed to their risk for chronic diseases had more stress and a higher prevalence of overweight and obesity than female LEOs who felt differently. CONCLUSIONS: Female LEOs have higher stress than male LEOs. The prevalences of hypercholesterolemia and diabetes are higher in female LEOs than that of the general female population. Thus, female LEOs may be at a greater risk for CVD than their male counterparts.

LBNP tolerance analyzed retrospectively using a structural equation model.

UNLABELLED: It would be useful to be able to predict tolerance to lower body negative pressure (LBNP) because of the association of low LBNP tolerance to low orthostatic tolerance. PURPOSE: To determine how well tolerance to LBNP can be modeled using laboratory variables assessed noninvasively. METHODS: There were 125 male and female college age and older (> 60 yr) subjects who underwent graded LBNP to presyncope. Tolerance was quantified by the LBNP tolerance index (LTI). Noninvasive variables assessed at rest and at presyncope were used to predict LTI via structural equation modeling (SEM). SEM can better address the correlation and variable interaction effects inherent in assessing orthostatic tolerance, e.g., multicollinearity, compared to traditional regression techniques. RESULTS: With SEM, the manifest variables of gender, % body fat, maximal change in heart rate from rest to presyncope (delta HR), and resting total peripheral conductance (TPC) explained 40% of the variance in LTI. All the variables had direct significant influences on LTI; in addition, % body fat mediated the influence of gender and age while AHR mediated the effects of TPC. An exaggerated HR response to LBNP was associated with an increased LBNP tolerance (beta = -0.396). CONCLUSION: About 40% of the variability in LBNP tolerance can be predicted using easily measured variables. Male gender, a potentiated HR response to LBNP, higher resting TPC, older age, and lower body fat are associated with an increased LBNP tolerance.

Milwaukee police department retirees: cardiovascular disease risk and morbidity among aging law enforcement officers.

This study explored the self-reported prevalence of cardiovascular disease (CVD) and accompanying risk factors among 165 male retirees 43 years and older (M = 56.2, SD = 7.1) from the Milwaukee Police Department (MPD) compared to 671 individuals of similar age and income who responded to the 2005 Wisconsin Behavioral Risk Factor Surveillance System (BRFSS). CVD and other risk factors were more prevalent in the MPD retirees than the general population (CVD 15.2% vs. 9.5%, p = .036; hypertension 51.5% vs. 36.2%, p = .001; hypercholesterolemia 62.4% vs. 44.4%, p = .001; overweight and obesity 85.1% vs. 74.7%, p = .005). In addition, other factors associated with CVD prevalence included working in law enforcement (odds ratio = 1.70; 95% confidence interval = 1.03 to 2.79). Results suggest an association between employment in law enforcement and an increase in CVD morbidity.

Comparative effectiveness of aerobic, resistance, and combined training on cardiovascular disease risk factors: A randomized controlled trial.

Although exercise has well-documented health benefits on cardiovascular disease (CVD), the benefit of combination exercise on CVD risk factors in individuals with elevated risk has not been fully elucidated. We compared the effects of aerobic, resistance, and a combination of both aerobic and resistance training on CVD risk factors including peripheral and central BP, cardiorespiratory fitness (CRF), muscular strength, body composition, blood glucose and lipids. Sixty-nine adults (58±7 years) with an elevated blood pressure or hypertension, overweight/obesity, and sedentary lifestyle were randomized to one of the three 8-week exercise programs or a non-exercise control group. Participants in all three exercise groups had an equal total exercise time, 3 days/week (aerobic: 60 minutes/session vs. resistance: 60 minutes/session vs. combination: aerobic 30 minutes/session plus resistance 30 minutes/session). Combined training provided significant reductions in peripheral (-4 mmHg) and central diastolic BP (-4 mmHg), increase in CRF (4.9 ml/kg/min), increase in upper (4 kg) and lower (11 kg) body strength, and increase in lean body mass (0.8 kg) (p <0.05). Aerobic training only increased CRF (7.7 ml/kg/min), and reduced body weight (-1.0 kg) and fat mass (-0.9 kg) (p <0.05). Resistance training only increased lower body strength (13 kg) and reduced waist circumference (-1.7 cm) (p <0.05). However, neither aerobic or resistance training alone showed significant reductions in BP (p>0.05). Furthermore, a composite score of CVD risk factors indicated a greater reduction with combination training compared to the control group. In conclusion, among individuals at an increased risk for CVD, as little as 8-weeks of combined training may provide more comprehensive CVD benefits compared to time-matched aerobic or resistance training alone.

Associations of Health Club Membership with Physical Activity and Cardiovascular Health.

INTRODUCTION: This study evaluates whether a health club membership is associated with meeting the US physical activity (PA) guidelines and/or favorable cardiovascular health. METHODS: Using cross-sectional data of health club members (n = 204) and non-members (n = 201) from April to August 2013, this is the first study to our knowledge to examine a health club membership in relation to objectively measured cardiovascular health indicators including resting blood pressure, resting heart rate, body mass index, waist circumference, and cardiorespiratory fitness based on a non-exercise test algorithm. To determine the total PA and sedentary time, this study used a comprehensive PA questionnaire about both aerobic and resistance activities at the health club, as well as lifestyle activities in other settings, which was developed based on the International Physical Activity Questionnaire (IPAQ). RESULTS: The odds ratios (95% confidence interval) of meeting either the aerobic, resistance, or both aerobic and resistance PA guidelines for members compared to non-members were 16.5 (9.8-27.6), 10.1 (6.2-16.3), and 13.8 (8.5-22.4), respectively. Significant associations of health club membership with more favorable cardiovascular health outcomes and sedentary behavior were observed for resting heart rate (B: -4.8 b/min, p<0.001), cardiorespiratory fitness (B: 2.1 ml/kg/min, p<0.001), and sedentary time (B: -1.4 hours, p<0.001). Participants with a health club membership of >1 year had more favorable health outcomes, with a smaller waist circumference (men, B: -4.0 cm, p = 0.04; women, B: -3.4 cm, p = 0.06), compared to non-members. CONCLUSIONS: Health club membership is associated with significantly increased aerobic and resistance physical activity levels and more favorable cardiovascular health outcomes compared to non-members. However, longitudinal, randomized controlled trials would be clearly warranted as cross-sectional data prohibits causal inferences.