Blood Pressure Responses Are Dependent on Call Type and Related to Hypertension Status in Firefighters

Background: Impaired cardiovascular health is a concern for firefighters, with over 50% of line-of-duty deaths having cardiac causes. Many firefighters have hypertension and \u3c25% have their blood pressure (BP) controlled. The alarm response could be an unidentified cardiac risk, but interestingly, the BP response to different calls and on-the-job activity is unknown. Purpose: We aimed to measure the physiological stress resulting from different call types (fire, medical) and job activity (riding apparatus, pre-alert alarms) through ambulatory BP (ABP) monitoring in a population of firefighters. Materials and methods: During 111 12-h work shifts firefighters wore an ABP monitor. BP was measured at 30-min intervals and manual measurements were prompted when the pager went off or whenever they felt stress. Results: Firefighters were hypertensive (124.3 ± 9.9/78.1 ± 6.7 mmHg), overweight (30.2 ± 4.6 kg/m2), middle-aged (40.5 ± 12.6 years) and experienced (17.3 ± 11.7 years). We calculated an average 11% increase in systolic and 10.5% increase in diastolic BP with alarm. Systolic BP (141.9 ± 13.2 mmHg) and diastolic BP (84.9 ± 11.1 mmHg) and the BP surges were higher while firefighters were responding to medical calls compared to fire calls. Between BP groups we found that medical call systolic BP (p = .001, d = 1.2), diastolic BP (p = .017, d = 0.87), and fire call systolic BP (p = .03, d = 0.51) levels were higher in the hypertensive firefighters. Conclusion: This is the first report of BP surge responses to alarms and to occupational activities in firefighters, and medical calls elicited the largest overall responses.PLAIN LANGUAGE SUMMARYCardiovascular disease and impaired cardiovascular health are substantially more prevalent in firefighters, with over 50% of line-of-duty deaths being cardiac related.Many firefighters are diagnosed with high blood pressure (hypertension), which is known to increase the risk of heart attacks, strokes, heart disease, and other serious health complications.Upon stress, our body enacts the \u27fight or flight\u27 response where sympathetic nervous system activity triggers an immediate increase in heart rate and blood pressure. This response can be dangerous when surges reach extreme levels due to underlying impaired cardiovascular function. It is known that alarm sounds trigger a stress response.Firefighters respond to different alarms while on the job, each indicating different call types, such as a house fire or a medical emergency. Due to the prevalence of impaired cardiovascular health in firefighters, the physical stress resulting from these alerts is cause for concern.The blood pressure surge response to different call types and job activities in healthy and hypertensive firefighters had not been measured before this study.Through the ambulatory blood pressure monitoring of 111 on-duty firefighters, this study discovered that medical calls caused the greatest blood pressure and heart rate surge.Also, firefighters with hypertension experienced a greater blood pressure surge in response to alarms than their non-hypertensive co-workers

The effects of whole‐body vibration amplitude on glucose metabolism, inflammation, and skeletal muscle oxygenation

Whole‐body vibration (WBV) is an exercise mimetic that elicits beneficial metabolic effects. This study aims to investigate the effects of WBV amplitude on metabolic, inflammatory, and muscle oxygenation responses. Forty women and men were assigned to a high (HI; n = 20, Age: 31 ± 6 y) or a low‐amplitude group (LO; n = 20, Age: 33 ± 6 y). Participants engaged in 10 cycles of WBV [1 cycle =1 min of vibration followed by 30 s of rest], while gastrocnemius muscle oxygen consumption (mVO(2)) was assessed using near‐infrared spectroscopy (NIRS). Blood samples were collected PRE, POST, 1H, 3Hs, and 24H post‐WBV and analyzed for insulin, glucose, and IL‐6. In the LO group, Homeostatic Model Assessment for Insulin Resistant (HOMA‐IR) at 3 h (0.7 ± 0.2) was significantly lower compared to PRE (1.1 ± 0.2; p = 0.018), POST (1.3 ± 0.3; p = 0.045), 1H (1.3 ± 0.3; p = 0.010), and 24H (1.4 ± 0.2; p < 0.001). In addition, at 24H, HOMA‐IR was significantly lower in the LO when compared to the HI group (LO: 1.4 ± 0.2 vs. HI: 2.2 ± 0.4; p = 0.030). mVO(2) was higher (p = 0.003) in the LO (0.93 ± 0.29 ml/min/100 ml) when compared to the HI group (0.63 ± 0.28 ml/min/100 ml). IL‐6 at 3H (LO: 13.2 ± 2.7 vs. HI: 19.6 ± 4.0 pg·ml(−1); p = 0.045) and 24H (LO: 4.2 ± 1.1 vs. HI: 12.5 ± 3.1 pg·ml(−1); p = 0.016) was greater in the HI compared to the LO group. These findings indicate that low‐amplitude WBV provides greater metabolic benefits compared to high‐amplitude WBV

Endothelin‐1 response to whole‐body vibration in obese and normal weight individuals

Upregulation of endothelin‐1 (ET‐1) is the hallmark of various cardiovascular diseases (CVD). The purpose of the present study was to assess the ET‐1 response to an acute bout of whole‐body vibration (WBV) in humans and to determine the role of adiposity. Twenty‐two participants volunteered for the study; they were grouped into overweight/obese [(OW/OB): n = 11, Age: 33 ± 4 years, Body mass index (BMI): 35 ± 10 kg/m(2)] or normal weight [(NW): n = 11, Age: 28 ± 7 years, BMI: 21 ± 2 kg/m(2)]. Participants engaged in 10 cycles of WBV exercise (1 cycle = 1 min WBV followed by 30 s of rest). Blood samples were analyzed for ET‐1 pre‐WBV (PRE), immediately post (POST), 1 h (1H), 3 h (3H), and 24 h (24H) post‐WBV. There was a significant time main effect of WBV on circulating ET‐1 (F = 12.5, p < 0.001); however, the ET‐1 response was similar (F = 0.180, p = 0.677) between groups. Specifically, compared to PRE, a significant increase in ET‐1 was observed at 1H (p = 0.017) and 3H (p = 0.025). In addition, concentrations of ET‐1 were significantly lower at 24H compared to PRE (p = 0.019), 1H (p < 0.001), and 3H (p < 0.001). Maximal oxygen uptake during WBV was similar between the two groups. Acute WBV resulted in an initial rise in ET‐1, followed by a significantly lower ET‐1 at 24H in both groups. Findings support the utility of routine WBV exercise to elicit a decrease in ET‐1 and improve CVD risk, similar to what has been reported with traditional modes of exercise

Blood Pressure of Firefighters and Emergency Medical Technicians (EMT) in Response to Emergency Calls

High levels of stress can lead to a higher resting blood pressure (BP) eventually leading to hypertension and increased risks for cardiovascular disease (CVD). Sources of stress can be a result of many factors but often stem from one’s occupation and lifestyle. There is an association between work stress, an increased heart rate, and systolic BP, which are all risk factors of CVD. Levels of stress can vary depending on the specific occupation. Emergency medical technicians (EMT), first responders, and firefighters (FF) have some of the most stressful jobs due to the demands of the occupation. Studies have demonstrated that EMTs, paramedics, and FF experience increased systolic and diastolic BP as well as higher heart rate during a work day. Importantly, sudden cardiac events are the number one cause of in-line duty death of volunteer FF, so understanding how these risk factors are affected is important. Symptoms could potentially carry into everyday life and increase their risk of CVD earlier in life. This study monitors BP using an ambulatory BP cuff, during a typical work day or night to observe BP response in FF and EMTs to receiving emergency dispatch calls. Data so far suggests a systolic and diastolic BP surge in response to a pager call. There is also a potential relationship between years of experiences and pager surge as well as with the specific type of emergency call. This observation is suggesting specific emergency calls create more of a stress reaction in some responders over others

Blood Pressure and Cardiovascular Responses to Emergency Calls in Volunteer Firefighters and Emergency Medical Technicians

Hypertension and obesity are both primary risk factors for cardiovascular (CV) disease. Among the firefighter (FF) population cardiac events remain the leading cause of line-of-duty deaths. Work related stress can cause a surge in heart rate and blood pressure (BP) and studies have noted that FF and Emergency Medical Technicians (EMTs) have increased heart rate and BP throughout the day. Thus, understanding the risk factors associated with work related stress in FF and EMTs, including BP surges and CV disease risk are important factors in continual need of study

Endogenous estradiol contributes to vascular endothelial dysfunction in premenopausal women with type 1 diabetes

Abstract Background Endogenous estrogen is cardio-protective in healthy premenopausal women. Despite this favorable action of estrogen, animal models depict a detrimental effect of estradiol on vascular function in the presence of diabetes. The present study sought to determine the role of endogenous estradiol on endothelial function in women with type 1 diabetes. Method 32 women with type 1 diabetes (HbA1c = 8.6 ± 1.7%) and 25 apparently healthy women (HbA1c = 5.2 ± 0.3%) participated. Flow-mediated dilation (FMD), a bioassay of nitric-oxide bioavailability and endothelial function was performed during menses (M) and the late follicular (LF) phase of the menstrual cycle to represent low and high concentrations of estrogen, respectively. In addition, a venous blood sample was collected at each visit to determine circulating concentrations of estradiol, thiobarbituric acid reactive substances (TBARS), and nitrate/nitrite (NOx), biomarkers of oxidative stress and nitric oxide, respectively. Data were collected in (1) 9 additional women with type 1 diabetes using oral hormonal birth control (HBC) (HbA1c = 8.3 ± 2.1%) during the placebo pill week and second active pill week, and (2) a subgroup of 9 demographically matched women with type 1 diabetes not using HBC (HbA1c = 8.9 ± 2.1%). Results Overall, estradiol was significantly increased during the LF phase compared to M in both type 1 diabetes (Δestradiol = 75 ± 86 pg/mL) and controls (Δestradiol = 71 ± 76 pg/mL); however, an increase in TBARS was only observed in patients with type 1 diabetes (ΔTBARS = 3 ± 13 µM) compared to controls (ΔTBARS = 0 ± 4 µM). FMD was similar (p = 0.406) between groups at M. In addition, FMD increased significantly from M to the LF phase in controls (p = 0.024), whereas a decrease was observed in type 1 diabetes. FMD was greater (p = 0.015) in patients using HBC compared to those not on HBC, independent of menstrual cycle phase. Conclusion Endogenous estradiol increases oxidative stress and contributes to endothelial dysfunction in women with diabetes. Additionally, HBC use appears to be beneficial to endothelial function in type 1 diabetes

Effects of circuit exercise training on vascular health and blood pressure

As the global burden of cardiovascular disease (CVD) rises, public health-related interventions aimed at prevention of heart disease have gained medical attention. Clinical research reports that exercise is a protective risk factor associated with CVD and that clinicians need to provide exercise recommendations to patients. Nevertheless, physical inactivity remains a public health problem. In certain populations, like firefighters (FF), increased risk of CVD is especially concerning. The workload FF face is extreme, 50% of line-of-duty deaths (LODD) in FF are cardiac-related, and research on the volunteer FF population is scarce. Government regulations do not require volunteer FF companies to have fitness testing or programming, so exercise intervention studies are necessary to improve the burden of CVD risk in this population. Therefore, this study examined the effects of a 4-week exercise circuit training (CT) intervention on vascular health and fitness in volunteer FF (N = 27) from the Philadelphia PA area compared to a control group of Non-FF (N = 25). Carotid artery intima-media thickness (IMT), brachial artery flow-mediated dilation (FMD), augmentation index, and pulse pressure (PP), brachial and central blood pressure (BP) and fitness were measured pre- and post- intervention. Overall, volunteer FF had more significant improvements (p < 0.05) in vascular health measures (FMD, IMT, and PP). In both groups, we also found that brachial and central BP decreased with exercise. We show that a 4 week CT program can improve vascular structure and function in the volunteer FF population, suggesting that clinicians may be able to reduce or prevent cardiac LODD by exercise. Keywords: Vascular health, Flow-mediated dilation, Blood pressure, Exercise, Carotid artery intima media thickness, Volunteer firefighter

SARS-CoV-2 Spike Protein Stimulates Macropinocytosis in Murine and Human Macrophages via PKC-NADPH Oxidase Signaling

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). While recent studies have demonstrated that SARS-CoV-2 may enter kidney and colon epithelial cells by inducing receptor-independent macropinocytosis, it remains unknown whether this process also occurs in cell types directly relevant to SARS-CoV-2-associated lung pneumonia, such as alveolar epithelial cells and macrophages. The goal of our study was to investigate the ability of SARS-CoV-2 spike protein subunits to stimulate macropinocytosis in human alveolar epithelial cells and primary human and murine macrophages. Flow cytometry analysis of fluid-phase marker internalization demonstrated that SARS-CoV-2 spike protein subunits S1, the receptor-binding domain (RBD) of S1, and S2 stimulate macropinocytosis in both human and murine macrophages in an angiotensin-converting enzyme 2 (ACE2)-independent manner. Pharmacological and genetic inhibition of macropinocytosis substantially decreased spike-protein-induced fluid-phase marker internalization in macrophages both in vitro and in vivo. High-resolution scanning electron microscopy (SEM) imaging confirmed that spike protein subunits promote the formation of membrane ruffles on the dorsal surface of macrophages. Mechanistic studies demonstrated that SARS-CoV-2 spike protein stimulated macropinocytosis via NADPH oxidase 2 (Nox2)-derived reactive oxygen species (ROS) generation. In addition, inhibition of protein kinase C (PKC) and phosphoinositide 3-kinase (PI3K) in macrophages blocked SARS-CoV-2 spike-protein-induced macropinocytosis. To our knowledge, these results demonstrate for the first time that SARS-CoV-2 spike protein subunits stimulate macropinocytosis in macrophages. These results may contribute to a better understanding of SARS-CoV-2 infection and COVID-19 pathogenesis

Heart Rate and Blood Pressure Responses to Gear Weight Under a Controlled Workload

Objective: To compare the effects of personal protective equipment (PPE) weight on blood pressure (BP) and heart rate (HR), between volunteer firefighters (FF) and athletes. Methods: Athletes and FF were matched by body size and came to the lab twice for two treadmill tests. The “Regular” test was completed in normal fitness clothing, and PPE test was completed in full structural PPE with monitoring of HR assessment every minute and BP each stage. Results: In the FF cohort, all submaximal HR and BP levels were different. HRmax and VO2max were also different (all P \u3c 0.05). In athletes, HRmax was higher in Regular test than PPE. Conclusions: Future research should examine the effect of different PPE weights on HR and BP responses

Effects of 4-Week Lifestyle Intervention on Fitness Levels of Adults

Cardiovascular disease (CVD) has been identified as a leading cause of death in the United States, with more than two million Americans having a heart attack or a stroke and close to a million deaths each year. Research shows that one of the independent risk factors for CVD is increased sedentary time. Sedentary behaviors predominate modern life, and there are numerous negative health effects associated with inactivity. Physical fitness is inversely related to mortality, and it is believed that by simply decreasing sedentary time and increasing exercise time, cardiovascular risk factors and vascular health measures will improve. Previous studies have found that four weeks of exercise reduces blood pressures, leads to fat weight loss, and improves fitness