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Human physiology, hazards and health risks
Published in Stephen Battersby, Clay's Handbook of Environmental Health, 2023
Revati Phalkey, Naima Bradley, Alec Dobney, Virginia Murray, John O’Hagan, Mutahir Ahmad, Darren Addison, Tracy Gooding, Timothy W Gant, Emma L Marczylo, Caryn L Cox
The sympathetic nervous system is active in states of emotional excitement and stress and gives rise to what has been called the ‘flight or fight’ reaction. Increased sympathetic nerve activity causes the heart to beat faster and increases the force of contraction of the ventricles of the heart (the force with which the heart muscle contracts) which result in an increase in the output from the heart (cardiac output). Therefore, the blood pressure increases. In addition, the pupils of the eye dilate, the air passages increase in diameter allowing an individual to breathe in more air, and also contracts the muscles associated with sweat glands and skin causing the hair to ‘stand on end’ and form goose pimples. The rate at which breathing occurs also increases due to excitement of the respiratory centres in the brain. In addition, sympathetic stimulation slows down the contractions of the digestive tract.
Environmental Health
Published in Lorris G. Cockerham, Barbara S. Shane, Basic Environmental Toxicology, 2019
Camille J. George, William J. George
Noise can be stressful for many people. This function of noise was clearly used for survival by our primitive ancestors. Loud noises warned of the approach of hostile tribes or dangerous animals and initiated the “fight or flight” response. This immediate response from the sympathetic nervous system results in an increase in heart and respiration rates, blood pressure, and muscle contraction. Chronic exposure to noise can result in headaches, ulcers, colitis, and even elevated serum cholesterol (Nadakavukaren, 1986). The necessity for such an “alert” system is evident in a primitive setting; however, this survival reaction has become a nuisance in modern man. The noises that trigger this system may not be associated with impending danger. The noises are now man-made and often chronic in nature. Such exposure results in a chronic stimulation of the sympathetic nervous system and the production of stress which affect millions of people in society today. Factory workers in noisy environments have more medical problems, especially respiratory infections, than fellow workers in quiet settings. Rhesus monkeys exposed to noisy environments similar to that of a factory setting, have displayed a 30% increase in blood pressure. This hypertension continued for some time after the noise was reduced. The study suggests that noise can result in adverse medical conditions that may not be readily relieved by removal of the source (Terry, 1979).
Effect of smoking on superoxide dismutase levels in DM with pulmonary TB patients
Published in Cut Adeya Adella, Stem Cell Oncology, 2018
M.I. Sari, S.S. Widjaja, Z. Amir, D.M. Darlan, D.D. Wijaya
Cigarette smoke is one of the exogenous sources of free radicals (oxidants). This is a factor in the occurrence of systemic disease and organ damage, including the pancreas. It happens via the pathway of the phosphatidylinositol-3-kinase enzyme. Inhibition of this enzyme causes a decrease of adiponectin secretion. This process can decrease the insulin sensitivity, which directly disrupts the process of glucose metabolism (Hilawe et al., 2015). Oxidative stress also increases the levels of the hormones epinephrine and norepinephrine. These hormones affect the sympathetic nervous system and increase the rate of gluconeogenesis and glycogenolysis that causes hyperglycaemia (Vu et al., 2014). Both of these pathways will cause metabolic disorders such as Diabetes Mellitus (DM) (Hilawe et al., 2015; Vu et al., 2014). The condition of hyperglycaemia in people with DM will lead to auto oxidative glucose reactions, protein glycation and the activation of polyol metabolism pathways that will accelerate the formation of free radicals, and this can cause damage to the organs.
Moderate continuous- and high-intensity interval training elicit comparable cardiovascular effect among middle-aged men regardless of recovery mode
Published in European Journal of Sport Science, 2023
Blake E. G. Collins, Cheyne Donges, Robert Robergs, Joshua Cooper, Kristie Sweeney, Michael Kingsley
Despite advances in medical treatments and lifestyle interventions, cardiovascular disease (CVD) remains the leading cause of mortality in developed nations (Australian Institute of Health and Welfare, 2017; Bots et al., 2017; de Lucia et al., 2019). Males remain at higher risk for adverse events, with 40–60 years of age identified as a transitional stage of disease development (Australian Institute of Health and Welfare, 2017; Bots et al., 2017). Elevated adiposity, sedentary lifestyle, and adverse lipid profile are established indicators of future cardiovascular risk (Crichton & Alkerwi, 2015); however, autonomic nervous system (ANS) dysfunction has become a topic of interest due to the direct mechanistic role in disease pathogenesis (de Lucia et al., 2019; Hadaya & Ardell, 2020). Regulating all aspects of cardiac function, deregulation of cardiac and vascular adrenergic signalling can result in a hyperactive sympathetic nervous system (SNS) with adverse effects on myocardial and endothelial function (de Lucia et al., 2019; Hadaya & Ardell, 2020). Therefore, interventions aimed at improving endothelial health, ANS modulation, and cardiovascular function of middle-aged men may decrease future disease burden.
Obstructive sleep apnea risk and hearing impairment among occupational noise-exposed male workers
Published in Archives of Environmental & Occupational Health, 2023
Seunghyeon Cho, Won-Ju Park, Ji-Sung Ahn, Dae-Young Lim, Su-Hwan Kim, Jai-Dong Moon
In patients with OSA, repeated apnea episodes lead to chronic hypoxemia and decreased oxygen saturation levels. Chronic hypoxemia and decreased oxygen saturation levels in patients with OSA may be detrimental for auditory transduction and transmission mechanisms. The intermittent hypoxia and reoxygenation that repeatedly occur in patients with OSA result in the production of reactive oxidative stress (ROS), endothelial dysfunction, and activation of the inflammatory cascade. These harmful stimuli can cause activation of the sympathetic nervous system, promotion of oxidative stress and systemic inflammation, and impairment of vascular endothelial function.29 Also, hypoxemia can result in peripheral nerve injury by harming the vasa nervorum.30,31 Patients with OSA had significantly lower optoacoustic emissions, with damage to hair cells being considered a possible mechanism.15 Studies have shown that poor sleep quality (such as that observed in patients with insomnia) is a risk factor for hearing damage in occupational noise-exposed workers.32 There is a possibility that damage caused by noise during working hours is less likely to recover during sleep owing to insomnia or OSA.
Stress and burnout among attending and resident physicians in the ED: a comparative study
Published in IISE Transactions on Healthcare Systems Engineering, 2020
Vishnunarayan Girishan Prabhu, Kevin Taaffe, Ronald Pirrallo, Dotan Shvorin
HRV, which is the change in the time between successive heartbeats, is a reliable reflection of many physiological factors (Acharya et al., 2006). It has been used as a quantitative marker to understand the interplay between the sympathetic and parasympathetic nervous systems. The sympathetic nervous system is our fight and flight response, whereas the parasympathetic is the rest and digest response. The former activates during high stress, anxiety, or fear while the latter helps the body to maintain homeostasis (McCorry, 2007). Although HRV can be analyzed and interpreted using a variety of methods, the most common and reliable methods used are time domain and frequency domain metrics (Malik et al., 1996). Hence for analysis, we considered both time domain and frequency domain metrics of the HRV.