Discovered: why happier people are happier, a bleak outlook for frogs, a theoretically good snack to keep you awake, an odd finding in a heart-attack study, and why smoggier living may lead to strokes.

• Why frogs have a reason to be stressed. Lately we've seen a spate of research detailing how certain animals react to stress (dragonflies, for instance, just keel over in certain circumstances while surgeonfish enlist other fish for a helpful massage). It looks like a few amphibians have a reason to be worried today, finds a study in Nature, as relayed by the Associated Press: "Scientists have long known that amphibians are under attack from a killer fungus, climate change, and shrinking habitat. In the study appearing online Wednesday in the journal Nature, computer models project that in about 70 years those three threats will spread, leaving no part of the world immune from one of the problems." In summary, says one zoologist to the AP: "It's no fun being a frog." In 70 years, that is. [Associated Press]

• An odd thing happened in one very large study analyzing heart-attack death rate. A study published by the American Heart Association found that the people who were more likely to die from a first-time heart attack weren't those people who exhibited normal warning signs ("high blood pressure, bad blood lipids, diabetes") of risk, The Los Angeles Times reported. Researchers, the newspaper noted, didn't know why this was, but explained it this way: "People who already have risk factors for heart disease are likely to be on medications such as asperin , statins, beta blockers, and so on, so even if they have a heart attack, the attack may be less serious than those experienced by people who were on no meds." [The Los Angeles Times]

Read the full story at The Atlantic Wire.