For athletes, there's no place like home
Home field advantage isn't just a theory: with the Winter Olympics in Sochi under way, psychological scientists in Britain say it's backed by scientific support. Reviewing existing research on sports competition, they found that home crowds or travel fatigue can influence the psychological states of competitors, coaches, and officials, ultimately affecting their behaviour in ways that tend to favour home athletes. Players also have a natural tendency to defend their home turf. However, cortisol, a stress hormone, is higher on home turf, which could lead to worse performance.
Adolescents' salt intake linked to obesity, inflammation
Most adolescents consume too much salt, and this is linked with fatness and inflammation, regardless of how much food they eat, according to a study in the journal Paediatrics. In the study of 766 healthy teens in the US state of Georgia, 97 per cent self-reported exceeding the 1,500 milligrams of sodium daily maximum recommended by the American Heart Association. These adolescents had high levels of tumour necrosis factor alpha, which is secreted by immune cells and contributes to chronic inflammation as well as auto-immune diseases like lupus and arthritis. They also had high levels of leptin, a hormone produced by fat cells that normally suppresses appetite and burns fat, but at chronically high levels can have the opposite effects.
Colds during pregnancy may lead to childhood asthma
Women who have more common colds and viral infections during pregnancy are more likely to have a baby who develops asthma or allergies in childhood, finds a study in the Annals of Allergy, Asthma and Immunology. Researchers studied 513 pregnant women in Germany, and their 526 children. Questionnaires were done during pregnancy and regularly till the children were age five. Three in five families had a parent with asthma, hay fever or atopic dermatitis. If both parents have allergies, the child has a 75 per cent chance of being allergic; it's 10 to 15 per cent if neither parent has an allergy.