More sex may not always make you happier, according to new research published by the Society for Personality and Social Psychology. 

"Although more frequent sex is associated with greater happiness, this link was no longer significant at a frequency of more than once a week," lead researcher Amy Muise said. "Our findings suggest that it's important to maintain an intimate connection with your partner, but you don't need to have sex everyday as long as you're maintaining that connection."

Some previous studies, and a plethora of articles and self-help books, have claimed that more sex equals more happiness. But this study, based on surveys of more than 30,000 Americans collected over four decades, is the first to find that association is not there after couples report having sex more than once a week on average. The study was not designed to identify the causal process, so does not tell us whether having sex up to once a week makes couples happier, or being in a happy relationship causes people to have more frequent sex (up to once a week).

"We found that fitness level had the strongest association with physical activity, followed by gender and season. This means that fit older adults were more active than the unfit, females were more active than males and physical activity was higher in the warmer months of the year. In addition we found that higher education was associated with higher physical activity for males, but not for females. Among other interesting results, we found that the social environmental correlates, such as social support and living situation, were not associated with physical activity among the elderly", says the two first authors of the study, Hallgeir Viken and Nils Petter Aspvik, PhD candidates at NTNU.

In the study newly published in the Journal of Aging and Physical Activity, researchers from the K.G. Jebsen Center for Exercise in Medicine - Cardiac Exercise Research Group (CERG) and the Department of Sociology and Political Science at the Norwegian University of Science and Technology (NTNU) Norway have examined how background factors (correlates) are associated with overall physical activity among older adults.

Liberia and Sierra Leone, two of the countries worst affected by the Ebola outbreak, are now virus-free according to the World Health Organisation.

On 7 November, Sierra Leone had gone 42 days without any new cases of Ebola, allowing the World Health Organisation (WHO) to declare the country free of the virus. It is an important milestone for the West African country, as the country has recorded 14,089 cases of the disease since December 2013, almost half of the total that were reported to have caused the outbreak (28,571).

Diets high in meat may lead to an increased risk of developing renal cell carcinoma (RCC) through intake of carcinogenic compounds created by certain cooking techniques, such as barbecuing and pan-frying. As part of a new study from The University of Texas MD Anderson Cancer Center, published online this week in the journal CANCER, researchers also discovered that individuals with specific genetic mutations are more susceptible to the harmful compounds created when cooking at high temperatures.

Landmark research by The George Institute for Global Health has found that exercise can save lives, with an increase in the number of steps walked each day having a direct correlation with long term mortality.

Study author Professor Terry Dwyer said this was the first time research had been able to make the link between exercise, measured directly through pedometers, and reduced mortality over time in people who appeared healthy at the outset.

'Inactivity is a major public health problem, with conditions like obesity costing the economy tens of billions of dollars every year,' Prof Dwyer said. 'This shows more clearly than before that the total amount of activity also affects life expectancy.

Use of low energy sweeteners (LES) in place of sugar, in children and adults, leads to reduced calorie intake and body weight – and possibly also when comparing LES beverages to water – according to a review led by researchers at the University of Bristol published in the International Journal of Obesity today.

For the first time, all available science was integrated into a single review to evaluate the real impact of LES, such as saccharin, aspartame, sucralose and stevia, on energy intake (EI) and body weight (BW) over the short- and long-term.  A considerable weight of evidence confirmed that consuming LES instead of sugar helps reduce relative energy intake and body weight. 

Maybe Linus Pauling was on to something after all. Decades ago the Nobel Prize–winning chemist was relegated to the fringes of medicine after championing the idea that vitamin C could combat a host of illnesses, including cancer. Now, a study published online today in Science reports that vitamin C can kill tumor cells that carry a common cancer-causing mutation and—in mice—can curb the growth of tumors with the mutation.

If the findings hold up in people, researchers may have found a way to treat a large swath of tumors that has lacked effective drugs. "This [could] be one answer to the question everybody's striving for," says molecular biologist Channing Der of the University of North Carolina, Chapel Hill, one of many researchers trying to target cancers with the mutation. The study is also gratifying for the handful of researchers pursuing vitamin C, or ascorbic acid, as a cancer drug. "I'm encouraged. Maybe people will finally pay attention," says vitamin C researcher Mark Levine of the National Institute of Diabetes and Digestive and Kidney Diseases.

By licking a wound it heals faster -- this is not simply popular belief, but scientifically proven. Our saliva consists of water and mucus, among other things, and the mucus plays an important role. It stimulates white blood cells to build a good defense against invaders, according to a group of researchers at Lund University in Sweden together with colleagues from Copenhagen and Odense in Denmark.

"White blood cells are among other places located in the oral mucosa, and they represent the body's first line of defence against infectious agents. The mucus in the mouth causes the white blood cells to throw out a 'net' that traps bacteria", explains Ole Sørensen from the Division of Infection Medicine.

A study just published by the Harvard T.H. Chan School of Public Health has linked a building’s indoor air quality directly to its occupants’ cognitive function. Cognitive function is defined as the cerebral activities that lead to knowledge including acquiring information, reasoning, attention, memory and language.

The revolutionary finding of this study is that lowering indoor air levels of carbon dioxide and volatile organic compounds (VOCs) improves human cognitive function. In other words: Cleaner air makes us smarter!

A new study to be published online November 5 in the American Journal of Psychiatry casts a shadow on light therapy's status as the gold standard for treating SAD, or seasonal affective disorder. 

While the treatment was effective at addressing acute episodes of SAD, a SAD-tailored version of cognitive-behavioral therapy (CBT) was significantly better at preventing relapse in future winters, the study found. Led by University of Vermont psychology professor Kelly Rohan, the research initiative, funded by a $2 million grant from the National Institute of Mental Health, is the first large scale study to examine light therapy's effectiveness over time.