Does stress really shortens life

Biological stress begins with the very basic processes in the body that produce and use energy. We eat foods and we breathe, and our body uses those two vital elements (glucose from food and oxygen from the air) to produce energy, in a process known as metabolism. You may already think of metabolism as it pertains to eating“. My metabolism is fast, so I can eat dessert," or “My metabolism has slowed down over the years, so I’m gaining weight.” Since metabolism is all about energy, it also encompasses breathing, 

circulating blood, eliminating waste, controlling body temperature, contracting muscles, operating the brain and nerves, and just about every other activity associated with living.

These everyday metabolic activities that sustain life also create “metabolic stress,” which, over time, results in damage to our bodies. Take breathing—obviously, we could not survive without oxygen, but oxygen is a catalyst for much of the damage associated with aging because of the way it is metabolized inside our cells. Tiny parts of the cell, called mitochondria, use oxygen to convert food into energy. While mitochondria are extremely efficient in doing this, they produce potentially harmful byproducts called oxygen free radicals. A variety of environmental factors, including tobacco smoke and sun exposure, can produce them, too. The oxygen free radicals react with and create instability in surrounding molecules. This process, called oxidation, occurs as a chain reaction: the oxygen free radical reacts with molecule “A” causing molecule “A” to become unstable; molecule “A” attempts to stabilize itself by reacting with neighboring molecule “B”; then molecule “B” is unstable and attempts to become stable by reacting with neighboring molecule “C”; and so on. This process repeats itself until one of the molecules becomes stable by breaking or rearranging itself, instead of 

passing the instability on to another molecule. 

Some free radicals are beneficial. The immune system, for instance, uses oxygen free radicals to destroy bacteria and other harmful organisms. Oxidation and its by-products also help nerve cells in the brain communicate. But, in general, the outcome of free radicals is damage (breaks or rearrangements) to 

other molecules, including proteins and DNA. Because mitochondria metabolize oxygen, they are particularly prone to free radical damage. As damage mounts, mitochondria may become less efficient, progressively 

generating less energy and more free radicals.

Scientists study whether the accumulation of oxidative (free radical) damage in our cells and tissues over time might be responsible for many of the changes we associate with aging. Free radicals are already implicated in many disorders linked with advancing age, including cancer, atherosclerosis, cataracts, and neurodegeneration.

Fortunately, free radicals in the body do not go unchecked. Cells use substances called antioxidants to counteract them. Antioxidants include nutrients, such as vitamins C and E, as well as enzyme proteins produced naturally in the cell, such as superoxide dismutase (SOD), catalase, and glutathione peroxidase. 

Many scientists are taking the idea that antioxidants counter the negative effects of oxygen free radicals a step further. Studies have tested whether altering the antioxidant defenses of the cell can affect the lifespan of animal models. These experiments have had conflicting results. NIA-supported researchers found that inserting extra copies of the SODgene into fruit flies extended the fruit flies’ average lifespan by as much as 30 percent. Other researchers found that immersing roundworms in a synthetic form of SOD and catalase extended their lifespan by 44 percent. However, in a comprehensive set of experiments, increasing or 

decreasing antioxidant enzymes in laboratory mice had no effect on lifespan. Results from a limited number of human clinical trials involving antioxidants generally have not supported the premise that adding antioxidants to the diet will support longer life. Antioxidant supplementation remains a topic of continuing investigation.

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stress and pressure

Stressed men make snap decisions when put under pressure

Stuck in a tricky situation and struggling to make a decision? It would be better if you leave it on your wife, scientists say.
Researchers at the University Of Southern California found that men respond differently to risky situations when under stress, while women tend to take their time before taking a decision.
They found that when the pressure is on, men charge ahead and make snap decisions for small rewards, while women are likely to take their time.
It's also found that the sexes have different brain activation patterns during the decision-making process, the Daily Mail reported.
Lead researcher Nichole Lighthall said: "Being more cautious and taking the time to make a decision will often be the right choice."
"It might be better to have more gender diversity on important decision because men and women offer differing perspectives," she said.
For the study, published in the Social Cognitive and Affective Neuroscience, the researchers gave volunteers a task of filling up a computer-simulated balloon with as much air as possible without popping the balloon.
Subjects earned from USD 4 to USD 45 based on their performance, with the men earning much more cash under stress.
Lighthall said that although men performed this task better, the more important conclusion may be that important decisions made under stress should include input from both genders.
After being subjected to stress, men appeared to be more motivated to act quickly while women would slow down.
For men under stress, playing a risk-taking game stimulated areas in the brain that are activated when one gets a reward or satisfies an addiction.
The same experiment found diminished brain activity for women in the same areas when they were stressed.
Lighthall said: "It appears women do not feel the drive to get a reward as much under stress."
Both stress responses have their benefits, Lighthall said, especially in areas with the need to weigh short-term gain and long-term benefits, such as the stock market, health decisions or retirement planning
But she found that when stress was absent, the behaviour and brain activation of both sexes was much more similar.
Men and women faced with tough decisions might improve their communication by waiting until a stressful situation has passed, Lighthall said.
In her earlier study, Lighthall had found that men under stress may be more likely to take risks, correlating to such real-life behaviour as gambling, smoking, unsafe sex and illegal drug use.