Sleep Archive

Scientists used to think that brain connections developed at a rapid pace in the first few years of life, until you reached your mental peak in your early 20s. Your cognitive abilities would level off at around middle age, and then start to gradually decline. We now know this is not true. Instead, scientists now see the brain as continuously changing and developing across the entire life span. There is no period in life when the brain and its functions just hold steady. Some cognitive functions become weaker with age, while others actually improve.

Some brain areas, including the hippocampus, shrink in size. The myelin sheath that surrounds and protects nerve fibers wears down, which can slow the speed of communication between neurons. Some of the receptors on the surface of neurons that enable them to communicate with one another may not function as well as they once did. These changes can affect your ability to encode new information into your memory and retrieve information that's already in storage.

Sleeping less doesn't have to be a consequence of growing older. A few adjustments to your sleep habits can help you sleep longer and better.

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If worries that you're not getting enough sleep are keeping you up at night, it's little wonder. A steady stream of reports has linked inadequate sleep to cognitive decline. Studies have also shown that people with sleep debts accrued by consecutive nights of sleeping too little are at higher risk of cardiovascular disease, depression, diabetes, high blood pressure, and weight gain.

Sleep is essential to good health, and not just because it knits up the raveled sleeve of care. It restores physical and mental performance, immune function, and metabolism. But how much sleep is necessary for those functions? It varies from person to person, says Dr. Elizabeth Klerman, a physiologist and physician at Harvard-affiliated Brigham and Women's Hospital who studies sleep.

How can you keep snacking from derailing your healthy eating program, not to mention weight control? Try these tips.

Don't skip meals. Skipping meals may seem like a good way to cut calories, but in fact this just makes you so hungry later in the day that you're vulnerable to devouring mega-portions of snack food, in order to supply your body with easily digested sugars.

Fish is an excellent source of protein, and its healthy oils protect against cardiovascular disease. Because a diet rich in seafood protects the heart and aids neurological development, fish remains an important component of a healthy diet.

However, nearly all fish and shellfish contain traces of mercury, a toxic metal, and some seafood contains other contaminants known as persistent organic pollutants (POPs). As small fish are eaten by larger fish up the food chain, concentrations of mercury and POPs increase, so that large, predatory deep-ocean fish tend to contain the highest levels. That makes it best to avoid eating large fish, such as shark, swordfish, tilefish, and king mackerel. As long as you avoid these higher sources of mercury, the benefits of eating fish far outweigh the risks of mercury in fish.