Exercise helps stave off depression. Swedish researchers genetically engineered mice to have high levels of a protein that builds up in muscles during exercise, then subjected these mice and a control group to sustained, low-level stress. After five weeks, the normal mice showed signs of depression, whereas the engineered mice did not. The researchers believe that the protein, PGC-1[alpha]1, helps turn a metabolite linked to depression into an acid that can be passed more easily out of the body. Co-author Jorge Ruas says the study proves that exercise should be prescribed for "the prevention and treatment of depression."

Coffee can improve memory, but don't drink too much. Researchers asked 160 people to look at pictures of objects, then gave them either a placebo or a tablet containing 200 milligrams of caffeine — equivalent to a strong cup of coffee. When the volunteers were shown a larger set of images the next day and asked to identify which ones were old, new, or similar, the caffeinated group was more likely to recognize very slight changes in the pictures. Dosage was crucial, however: Researchers found that 100-milligram tablets didn't improve memory, while 300-milligram doses caused headaches and jitteriness.



Standing up can delay the effects of aging. Swedish researchers split a group of men and women into two groups: Half were given a moderate exercise program and told to sit less; the other half continued their normal lives. After six months, scientists measured the volunteers' telomeres — caps on the ends of genes that generally shorten and fray with age. While the telomeres of subjects in the "normal" group had shortened, as expected, those in the active group had grown longer. Further tests confirmed that the biggest benefit didn't come from exercise but from time spent simply standing up. Sedentary behavior, says co-author Mai-Lis Hellénius, could be the "new health hazard of our time."

Eating vegetables reduces your risk of dying. Tracking the eating habits of 65,000 people over 12 years, researchers found that those who consumed seven or more portions a day — roughly half a cup each — of fresh fruits or vegetables reduced their risk of death 42 percent. Fresh vegetables were the most beneficial, with each portion reducing overall risk of death 16 percent; even minimal consumption helped, with one to three daily portions cutting the risk of death 14 percent. Consuming canned fruits, however, increased the statistical risk, probably because of the added sugar used in processing.



Living in Utah makes you happy. Residents of Provo-Orem, 40 miles south of Salt Lake City, reported the highest level of contentment in the U.S. last year. The results from the latest Gallup survey, which rates the well-being of residents in 189 metropolitan areas, found people's overall happiness to be higher in the Midwest and West and lower in the South. The Ashland-Huntington area, where Ohio, Kentucky, and West Virginia meet, came in last. The poll is based on more than 500,000 interviews covering everything from physical health to job satisfaction.

Fist bumping instead of shaking hands helps prevent the spread of bacteria. Researchers in Britain carried out a simple experiment: Wearing sterile gloves, they dunked their hands into a mild solution of E.coli bacteria, then shook hands, high-fived, or fist-bumped someone wearing uncontaminated gloves. The team found that a handshake transferred about twice as much bacteria as a high five and about 10 times more than a fist bump. This is partly because of the greater contact area of a handshake, but duration and pressure also play a part. Fist bumping, say the authors, is a "simple, free, and more hygienic alternative to the handshake."



Low expectations boost happiness. When researchers monitored the brain activity of volunteers as they played a game, they found the degree of happiness players experienced when they won depended on their expectations: the lower the expectations, the happier they were about winning. In the real world, scientists say, people with low expectations are likely to derive more pleasure from receiving gifts or going on vacation. "Happiness depends not on how well things are going," says neuroscientist Robb Rutledge, "but whether things are going better or worse than expected."