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Study suggests working more than 39 hours a week is bad for you

Study suggests working more than 39 hours a week is bad for you Science & Technology World Website


Putting in long hours at the office seems normal with projects to finish, paperwork to complete and those numbers to compile for the monthly meeting.

In Australia, about two in three work more than 40 hours a week at their full-time jobs.

Now science has confirmed that those who do more than 39 hours are putting their health at risk.

Research from the Australian National University (ANU) shows the work limit for a healthy life should be set at 39 hours a week instead of the 48-hour limit set internationally about 80 years ago.

The death by suicide last year of a 24-year-old Japanese woman, after working 105 overtime hours in one month, sparked an international debate on long working hours.

"Long work hours erode a person’s mental and physical health, because it leaves less time to eat well and look after themselves properly," says Huong Dinh from the ANU Research School of Population Health.

The researchers say Australia needs to do more to change attitudes to work and to support men to take time at home without penalty or prejudice.

Australians also need to dispel the widespread belief that people need to work long hours to do a good job.

"Despite the fact that women on average are as skilled as men, women on average have lower paid jobs and less autonomy than men, and they spend much more time on care and domestic work," says Dinh.

"Given the extra demands placed on women, it’s impossible for women to work long hours often expected by employers unless they compromise their health."

The study, published in the journal Social Science & Medicine, used data from about 8,000 Australian adults as part of the Household, Income and Labour Dynamics in Australia (HILDA) Survey.


Keeping your nights dark can provide a massive health boost

Study suggests working more than 39 hours a week is bad for you Science & Technology World Website


Today most people do not get enough sleep. The Centers for Disease Control and Prevention (CDC) has called insufficient sleep an epidemic. While we are finally paying attention to the importance of sleep, the need for dark is still mostly ignored.

That’s right. Dark. Your body needs it too.

Being exposed to regular patterns of light and dark regulates our circadian rhythm. Disruption of this rhythm may increase the risk of developing some health conditions including obesity, diabetes and breast cancer.

The physiological processes that control the daily cycle of sleep and wake, hunger, activity levels, body temperature, melatonin level in the blood, and many other physiological traits are called the endogenous circadian rhythm.

On its own, the endogenous circadian rhythm is nearly, but not exactly, 24 hours. Our bodies rely on the Sun to reset this cycle and keep it at precisely 24 hours, the length of our days. The light – and the dark – are important signals for the cycle. This circadian rhythm has developed over three billion years as life evolved on Earth in the context of the Sun’s day/night cycle. It is built deeply into our genetic makeup.

During the night, in the dark, body temperature drops, metabolism slows, and the hormone melatonin rises dramatically. When the Sun comes up in the morning, melatonin has already started falling, and you wake up. This natural physiological transition into and out of night is of ancient origin, and melatonin is crucial for the process to proceed as it should.

If you were to put someone in a dark cave with no time cues at all, the cycle will last about 24 hours, but not exactly. Without time cues like those from the Sun, eventually that person would become out of sync with people outside. In fact many profoundly blind people, who cannot perceive light, must cope with this de-synchronization in their daily lives.

Before electricity, people experienced bright, full-spectrum days of sunlight and dark nights. We slept in a different way than we do now. The dark lasted about twelve hours and during this time people slept for eight or nine hours in two separate bouts, and were awake, but in the dark, for another three or four hours.

Everything changed when electric lighting was invented in the latter part of the 19th century. Since then there has been an ever increasing assault on dark. Outdoor environments are relentlessly lit, and more and more people use computer tablets and smart phones at all hours, bathing their faces in bright blue light at times of day when they should be transitioning to nighttime physiology.

When people get away from the city and its artificial light to go camping, they often notice a marked improvement in their sleep. A recent study has verified this effect.

Today, most of us get too little light during the day and too much at night for our circadian rhythm to function at its best. It is the rare person who sleeps in a completely dark bedroom, and many people get very little sunlight because they work inside all day long.

What can you do for your circadian health? Get bright, blue light in the morning (preferably from the Sun), and use dim, longer wavelength light (more yellow and red like incandescent) in the evening. And sleep in the dark.

This will certainly improve sleep, and may reduce risk of later disease.


Nutrition linked to brain health and intelligence in older adults

Study suggests working more than 39 hours a week is bad for you Science & Technology World Website


A study of older adults links consumption of a pigment found in leafy greens to the preservation of "crystallized intelligence," the ability to use the skills and knowledge one has acquired over a lifetime.

The study is reported in the journal Frontiers in Aging Neuroscience.

Lutein (LOO-teen) is one of several plant pigments that humans acquire through the diet, primarily by eating leafy green vegetables, cruciferous vegetables such as broccoli, or egg yolks, said University of Illinois graduate student Marta Zamroziewicz, who led the study with Illinois psychology professor Aron Barbey. Lutein accumulates in the brain, embedding in cell membranes, where it likely plays "a neuroprotective role," she said.

"Previous studies have found that a person's lutein status is linked to cognitive performance across the lifespan," Zamroziewicz said. "Research also shows that lutein accumulates in the gray matter of brain regions known to underlie the preservation of cognitive function in healthy brain aging."

The study enrolled 122 healthy participants aged 65 to 75 who solved problems and answered questions on a standard test of crystallized intelligence. Researchers also collected blood samples to determine blood serum levels of lutein and imaged participants' brains using MRI to measure the volume of different brain structures.

The team focused on parts of the temporal cortex, a brain region that other studies suggest plays a role in the preservation of crystallized intelligence.

The researchers found that participants with higher blood serum levels of lutein tended to do better on tests of crystallized intelligence. Serum lutein levels reflect only recent dietary intakes, Zamroziewicz said, but are associated with brain concentrations of lutein in older adults, which reflect long-term dietary intake.

Those with higher serum lutein levels also tended to have thicker gray matter in the parahippocampal cortex, a brain region that, like crystallized intelligence, is preserved in healthy aging, the researchers report.

"Our analyses revealed that gray-matter volume of the parahippocampal cortex on the right side of the brain accounts for the relationship between lutein and crystallized intelligence," Barbey said. "This offers the first clue as to which brain regions specifically play a role in the preservation of crystallized intelligence, and how factors such as diet may contribute to that relationship."

"Our findings do not demonstrate causality," Zamroziewicz said. "We did find that lutein is linked to crystallized intelligence through the parahippocampal cortex."

"We can only hypothesize at this point how lutein in the diet affects brain structure," Barbey said. "It may be that it plays an anti-inflammatory role or aids in cell-to-cell signaling. But our finding adds to the evidence suggesting that particular nutrients slow age-related declines in cognition by influencing specific features of brain aging."

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