Eating too much fatty food, exercising too little and smoking can raise your future risk of heart disease. But there's another factor that can trigger your ticker more immediately: the air you breathe.
Previous studies have linked high exposure to environmental pollution to an increased risk of heart problems, but two analyses now show that poor air quality can lead to heart attack or stroke within as little as a few hours after exposure. In one review of the research, scientists found that people exposed to high levels of pollutants, including carbon monoxide and fine particulates emitted by cars and manufacturing facilities, were up to 5% more likely to suffer a heart attack within days of exposure than those with lower exposure. A separate study of stroke patients showed that even air that the U.S. Environmental Protection Agency considers to be of "moderate" quality and relatively safe for our health can boost the risk of stroke as much as 34% within 12 to 14 hours of exposure.
While the authors of both studies stress that these risks are relatively low for healthy people--and certainly modest compared with other risk factors such as smoking and high blood pressure--they are important to recognize because everyone is exposed to air pollution regardless of lifestyle choices. So stricter regulation by the EPA of pollutants may not only improve environmental air quality but could also become necessary to protect public health.
Memories naturally fade over time, and that's why aging is one of the strongest drivers of memory loss. But increasingly, studies suggest that certain lifestyle habits can hasten that decline as well. For example, one recent study of elderly people found that those who overate--consuming 2,143 to 6,000 calories a day--were twice as likely to have mild cognitive impairment, a precursor to Alzheimer's disease, as those who ate fewer than 1,526 calories daily. Their memory problems weren't severe enough to disrupt daily life but were noticeable to the participants or their loved ones. In another study among people ages 45 to 80, scientists found that those who didn't sleep well--waking up more than five times each hour--were more likely to have deposits of amyloid proteins, the hallmark of Alzheimer's disease, in their brains. Whether overeating or interrupted sleeping contributes to the Alzheimer's-disease process or whether they are side effects of the neurodegenerative disorder isn't clear, but the results suggest that our behaviors have more to do with our memory than we thought.
Stem Cells Fade Scars
Modern medicine can do a lot to heal a broken heart, but it hasn't yet been able to repair the scarring that forms after a heart attack. Now a study shows that the organ's own stem cells may shrink scarred tissue and promote growth of new heart cells. Researchers took biopsies from 17 heart-attack patients, cultivated heart stem cells from the samples and injected them back into the patients' organs. Over the course of a year, their heart scars receded 50% and new tissue grew, while untreated patients saw no change. More studies will determine whether stem-cell treatments not only prompt regrowth but also help improve the heart's pumping ability.