Aerobic fitness impacts sympathoadrenal axis responses to concurrent challenges

Gestalt clinical severity score (GCSS) as a predictor of patient severity of illness or injury

OBJECTIVE

To determine if clinical judgement is accurate to predict the severity of injury or illness, and can be used at patient arrival when other formal scoring systems are not yet available.

DESIGN

A multicenter pilot study using a prospective observational convenience sample of patients arriving by EMS to the emergency department (ED) or Trauma Center.

SETTING

Two urban, Level 1 trauma centers at academic tertiary care hospitals.

PATIENTS

Medical and trauma patients age 18 and older transported by EMS (N = 216). Exclusion criteria (prior to arrival): intubation, assisted ventilation (BVM or NPPV), CPR in progress, prisoners, or previously present motor or speech deficits.

MEASUREMENTS

Completion of a novel 15-point scale of Verbal, Motor, and Facial Expression within 1-2 min of arrival by a clinician outside of the treatment team. Primary endpoint was the immediate disposition from the ED or Trauma Center: Home, Brief Observation (<24 h), Admission to Floor, ICU (OR and IR as surrogates since these patients ultimately go to the ICU), or Morgue.

RESULTS

Univariate analysis revealed a strong, positive monotonic correlation between GCSS and disposition (Rho = 0.693, p < .0001). Multivariable logistic regression revealed the "best" model included GCSS and age (group 18-44 years old versus all the other age groups) (p < .0001). There was a 156% increase in the odds of being discharged home (versus being admitted) for a one-unit increase in GCSS (OR = 2.56, 95% CI 1.94, 3.37).

CONCLUSIONS

Physicians can make accurate predictions of severity of injury and illness using a gestalt method and the scoring system we have developed as patient disposition correlates well with GCSS score. GCSS is most accurate with the 18-44 age group.

Firefighters With Higher Cardiorespiratory Fitness Demonstrate Lower Markers of Cardiovascular Disease Risk

OBJECTIVE

High cardiorespiratory fitness (CRF) is associated with reduced markers of oxidative stress and cardiovascular disease (CVD) risk factors; however, this relationship has not been elucidated in firefighters. The purpose of this study was to examine differences in markers of CVD risk between firefighters who have either high or low levels of CRF.

METHODS

Forty-six firefighters participated in a maximal graded exercise test and a dual-energy x-ray absorptiometry scan and provided a fasted blood sample. V˙O 2max values were categorized based on American College of Sports Medicine guidelines to establish high- and low-fitness groups.

RESULTS

High fitness firefighters demonstrated significantly higher high-density lipoprotein cholesterol and lower markers of CVD risk: cholesterol, triglycerides, low-density lipoprotein cholesterol, insulin, homeostatic model assessment for insulin resistance, C-reactive protein, and advanced oxidation protein products concentrations.

CONCLUSION

Firefighters are encouraged to maintain high CRF to reduce risk of CVD.

Behavioral reinforcement of pathological exercise in anorexia nervosa

Pathological exercise in anorexia nervosa (AN) is a harmful behavior associated with a chronic course and poor prognosis. To date, no comprehensive theoretical model exists to describe pathological exercise in the context of AN, and as such, few treatments are effective at promoting direct and sustained pathological exercise extinction. Using a framework put forth by Wise & Koob (2014), debating the relative importance of positive and negative reinforcement in substance use, we present three hypotheses of behavioral reinforcement of exercise, encompassing biological, psychological, and environmental influences. Specifically, we argue that exercise is positively reinforced through receipt of biological and behavioral rewards, negatively reinforced through avoidance of aversive emotions, and that these two systems work in tandem over time to engrain pathological exercise as a habit. We then present suggestions for testing each of these hypotheses as future directions for the field.

Combined mental task and metaboreflex impair cerebral oxygenation in patients with type 2 diabetes mellitus

Cardiovascular regulation is altered by type 2 diabetes mellitus (DM2), producing an abnormal response to muscle metaboreflex. During physical exercise, cerebral blood flow is impaired in patients with DM2, and this phenomenon may reduce cerebral oxygenation (COX). We hypothesized that the simultaneous execution of a mental task (MT) and metaboreflex activation would reduce COX in patients with DM2. Thirteen individuals suffering from DM2 (6 women) and 13 normal age-matched controls (CTL, 6 women) participated in this study. They underwent five different tests, each lasting 12 min: postexercise muscle ischemia (PEMI) to activate the metaboreflex, control exercise recovery (CER), PEMI + MT, CER + MT, and MT alone. COX was evaluated using near-infrared spectroscopy with sensors applied to the forehead. Central hemodynamics was assessed using impedance cardiography. We found that when MT was superimposed on the PEMI-induced metaboreflex, patients with DM2 could not increase COX to the same extent reached by the CTL group (101.13% ± 1.08% vs. 104.23% ± 2.51%, P < 0.05). Moreover, patients with DM2 had higher mean blood pressure and systemic vascular resistance as well as lower stroke volume and cardiac output levels compared with the CTL group, throughout our experiments. It was concluded that patients with DM2 had reduced capacity to enhance COX when undertaking an MT during metaboreflex. Results also confirm that patients with DM2 had dysregulated hemodynamics during metaboreflex, with exaggerated blood pressure response and vasoconstriction. This may have implications for these patients' lack of inclination to exercise.

Physical exercise and catecholamines response: benefits and health risk: possible mechanisms

Beneficial effect of regular moderate physical exercise (PE) and negative effect of severe exercise and/or overtraining as an activator of the sympathetic nervous system (SNS) have been shown in numerous aspects of human health, including reduced risk of cardiovascular disease, neurological disease, depression, and some types of cancer. Moderate-to-vigorous PE stimulates the SNS activation, releasing catecholamines (CATs) adrenaline, noradrenaline, dopamine that play an important regulatory and modulatory actions by affecting metabolic processes and the immune system. Summary of the dispersed literature in this area and explanation of the biological mechanisms operating between PE-CATs and the immune system would lead to a better understanding of the beneficial and negative effects of PE on health. This overview aimed to: demonstrate representative literature findings on the exercise released CATs levels, major functions performed by these hormones, their interactions with the immune system and their effects on carbohydrate and lipid metabolism. Also, mechanisms of cytotoxic free radicals and reactive oxygen species (ROS) generation during CATs oxidation, and molecular mechanisms of CATs response to exercise are discussed to demonstrate positive and negative on human health effects. Owing to the large body of the subject literature, we present a representative cross-section of the published studies in this area. The results show a significant role of CATs in carbohydrate and lipid metabolism, immunity and as generators of ROS, depending on PE intensity and duration. Further investigation of the PE-CATs relationship should validate CATs levels to optimize safe intensity and duration of exercise and individualize their prescription, considering CATs to be applied as markers for a dose of exercise. Also, a better understanding of the biological mechanisms is also needed.

Effects of psychological stress during exercise on markers of oxidative stress in young healthy, trained men

PURPOSE

Those engaged in high stress occupations such as firefighters and military personnel are exposed to a variety of psychological and physiological stressors. The combination of mental and physical stress [i.e., dual stress challenges (DSC)] results in significant increases in stress hormones, which causes oxidative stress (OS) and contributes to elevated risk for cardiovascular disease. However, data are needed to determine the impact of DSC on markers of OS in exercise-trained individuals.

METHOD

Fourteen healthy trained men aged 21-30 yrs. participated in a randomized, cross-over design to investigate the impact of DSC on blood markers of OS. The exercise alone condition (EA) consisted of 35 min of cycling at 60% V̇O_{2 peak}. The DSC involved 20 min of mental stress challenges during exercise. Blood was sampled before exercise, as well as immediately, and 30 and 60 min after exercise and analyzed for glutathione (GSH), superoxide dismutase (SOD), hydrogen peroxide (H₂O₂) and advanced oxidation protein products (AOPP).

RESULT

No significant treatment × time interactions were found. No time effects were noted for SOD, or H₂O₂; however, AOPP were reduced at 30 (p = .034) and 60 min post exercise (p = .006). GSH was reduced at 30 (p = .009) and 60 min post exercise (p = .031).

CONCLUSION

These results indicate the OS response from DSC is not greater than that produced from EA in exercise trained men. Future work should investigate the impact of chronic resistance and endurance exercise training on OS resulting from DSC.