Obese people need more vitamin E, but actually get less

A recent study suggests that obese people with metabolic syndrome face an unexpected quandary when it comes to vitamin E - they need more than normal levels of the vitamin because their weight and other problems are causing ...

Nov 02, 2015
popularity16 comments 0

Easing PTSD symptoms with exercise

A novel trial at the QUT Health Clinics' exercise physiology clinic investigating the use of exercise to alleviate the symptoms of post-traumatic stress disorder (PTSD) is producing new findings on the needs of those with ...

Nov 04, 2015
popularity79 comments 0

Stress is a term that is commonly used today but has become increasingly difficult to define. It shares, to some extent, common meanings in both the biological and psychological sciences. Stress typically describes a negative concept that can have an impact on one’s mental and physical well-being, but it is unclear what exactly defines stress and whether or not stress is a cause, an effect, or the process connecting the two. With organisms as complex as humans, stress can take on entirely concrete or abstract meanings with highly subjective qualities, satisfying definitions of both cause and effect in ways that can be both tangible and intangible.

The term stress had none of its contemporary connotations before the 1920s. It is a form of the Middle English destresse, derived via Old French from the Latin stringere, "to draw tight." It had long been in use in physics to refer to the internal distribution of a force exerted on a material body, resulting in strain. In the 1920s and 1930s, the term was occasionally being used in biological and psychological circles to refer to a mental strain, unwelcome happening, or, more medically, a harmful environmental agent that could cause illness. Walter Cannon used it in 1926 to refer to external factors that disrupted what he called homeostasis.

Homeostasis is a concept central to the idea of stress. In biology, most biochemical processes strive to maintain equilibrium, a steady state that exists more as an ideal and less as an achievable condition. Environmental factors, internal or external stimuli, continually disrupt homeostasis; an organism’s present condition is a state in constant flux wavering about a homeostatic point that is that organism’s optimal condition for living. Factors causing an organism’s condition to waver away from homeostasis can be interpreted as stress. A life-threating situation such as a physical insult or prolonged starvation can greatly disrupt homeostasis. On the other hand, an organism’s effortful attempt at restoring conditions back to or near homeostasis, oftentimes consuming energy and natural resources, can also be interpreted as stress. In such instances, an organism’s fight-or-flight response recruits the body’s energy stores and focuses attention to overcome the challenge at hand. The ambiguity in defining this phenomenon was first recognized by Hans Selye in 1926 who loosely described stress as something that “…in addition to being itself, was also the cause of itself, and the result of itself." First to use the term in a biological context, Selye continued to define stress as “the non-specific response of the body to any demand placed upon it.” Present-day neuroscientists including Bruce McEwen and Jaap Koolhaas believe that stress, based on years of empirical research, “should be restricted to conditions where an environmental demand exceeds the natural regulatory capacity of an organism.” Despite the numerous definitions given to stress, homeostasis appears to lie at its core.

Biology has progressed in this field greatly, elucidating complex biochemical mechanisms that appear to underlie diverse aspects of stress, shining a necessary light on its clinical relevance and significance. Despite this, science still runs into the problem of not being able to settle or agree on conceptual and operational definitions of stress. Because stress is ultimately perceived as a subjective experience, it follows that its definition perhaps ought to remain fluid. For a concept so ambiguous and difficult to define, stress nevertheless plays an obvious and predominant role in the every day lives of humans and nature alike.

This text uses material from Wikipedia licensed under CC BY-SA

Latest Spotlight News

First language wires brain for later language-learning

You may believe that you have forgotten the Chinese you spoke as a child, but your brain hasn't. Moreover, that "forgotten" first language may well influence what goes on in your brain when you speak English or French today.

Genes for a longer, healthier life found

Out of a 'haystack' of 40,000 genes from three different organisms, scientists at ETH Zurich and a research consortium in Jena have found genes that are involved in physical ageing. If you influence only one of these genes, ...

Watching eyes prevent littering

People are less likely to drop litter if it has printed eyes on it, researchers at Newcastle University, UK, have found. An image of watching eyes reduced the odds of littering by around two thirds.

Anxiety can kill your social status

Neuroscientists at EPFL identify a brain region that links anxious temperament to low social status. The researchers were able to tweak social hierarchy in animals by using vitamin B3.

Wiring rules untangle brain circuitry

Our brains contain billions of neurons linked through trillions of synaptic connections, and although disentangling this wiring may seem like mission impossible, a research team from Baylor College of Medicine took on the ...

Higher cigarette taxes linked to fewer infant deaths

Higher taxes and prices for cigarettes are strongly associated with lower infant mortality rates in the United States, according to a new study from Vanderbilt University and the University of Michigan released Dec. 1 in ...

Researchers grow retinal nerve cells in the lab

Johns Hopkins researchers have developed a method to efficiently turn human stem cells into retinal ganglion cells, the type of nerve cells located within the retina that transmit visual signals from the eye to the brain. ...