Health News: sleep-ins can do you wonders

Weekend sleep-ins might prolong your life

Finally - a scientific endorsement for sleeping in.

It's well established that sleep plays an important role in our physical health, and that ongoing sleep deficiency could lead to an increased risk of various health issues. Swedish researchers have again highlighted this in their recent study, which found that adults under 65 who get five or fewer hours sleep for seven days a week have a higher risk of dying.

The researchers, from Stockholm University and the Karolinska Institute in Sweden, studied around 38,000 adults over the course of 13 years. They found those under 65 who got five hours of sleep or fewer for seven days a week had a 65% higher mortality rate than those getting six or seven hours sleep every day.

However, while their research showed it was healthier to sleep at least six or seven hours each night, they also concluded that there was no increased risk for people who slept five or fewer hours during the week but then managed eight or more hours sleep on weekend days.

So, according to the researchers, if you're struggling to get enough sleep during the week, a good lie-in at the weekend should counter any ill-effects from your working week.

Hanger, explained

We all know the feeling – you cannot focus, your stomach is snarling and you're losing your cool. If you don't get your hands on some food soon, you'll eat someone alive.

When you're "hangry" you're so hungry you get angry too.

And researchers from the University of North Carolina at Chapel Hill (UNC) in the US have been looking into the psychology behind why exactly we experience this emotional response to mounting hunger.

Scientists have previously explained that an empty stomach triggers an emotional response when a drop in blood sugar causes the body to release a torrent of hormones, including stress and adrenaline and a gene called neuropeptide Y, which is associated with aggression. The hungrier you get, the more hormones are released, making you more stressed and ultimately "hangry."

To better understand the psychological mechanisms behind hanger, the UNC researchers conducted experiments with about 600 people. Their study found that being in a stressful situation is more likely to transform a person's hunger into hanger. One particular experiment involved putting participants in an annoying situation, where they were blamed for a technological malfunction and made to repeat a tedious task.

Those who were hungry were more likely to be frustrated and, when asked to evaluate the research assistant's performance, give negative feedback.

Although it's called "hanger;" the researchers said the stress caused by an empty stomach isn't specific to anger – but rather intense negativity in general. They also said though hunger and negative emotions are part of life, people who are conscious of their feelings and emotions should be able to reduce their chances of getting hangry.

Boxers are best

Men have long been told that if they want to give themselves the best chance of conceiving they should ditch the tight-fitting underwear and opt for boxers instead. Although the science has been mixed, it's been thought that the higher temperatures associated with wearing tight knickers could damage sperm production.

Now, a new study from the Harvard T.H Chan School of Public Health has further verified this oft-cited adage, with more evidence to suggest sperm quality is linked to underwear choice.

The biggest study of its kind, researchers used a sample size of 656 men, who provided semen and blood samples. They also answered questions about their diets, exercise and other lifestyle variables, as well as – importantly – what kind of underwear they wore. Researchers looked at sperm quantity and quality, including DNA damage and hormone levels.

What they found was that those who wore tight-fitting underwear, and therefore had hotter scrotums, tended to have lower sperm counts and sperm concentration, as well as higher levels of the follicle-stimulating hormone (FSH) – a sex hormone that stimulates the cells that produce sperm.

Although the presence of this hormone might seem counterintuitive in men with lower quality sperm, the researchers seem to think it is a compensatory mechanism – when the sperm production is damaged by the heat from tight-fitting underwear, the body responds by producing more FSH to try and fix the problem.