The Effects of Aging and How Exercise Counteracts Them

• Motor neurons die, particularly from age 60 onward. This causes connections between muscle fibers to wither — and that, in turn, eventually leads to loss and shrinking of muscle fibers. As a result, muscles get smaller and a person gets weaker, says Sandra Hunter, an associate professor of exercise science at Marquette University in Milwaukee. "Physical activity can offset some of that," she says. "But there is this biological aging process going on — the neurons will die regardless of how ...

 Exercise During Pregnancy

There are two main reasons for concern about exercising during pregnancy. One is that it may reduce the baby's oxygen supply, since exercise, like other sources of stress, reduces blood flow to the uterus. Another risk is overheating. As we have already seen, fetal development is highly sensitive to temperature, and elevations of more than 2^0 C (or above 1020F) can increase the risk of miscarriage and affect the formation of the brain and eyes. Despite these theoretical concerns, there is ...

 What Newborns Hear and Learn in the Womb

Another experiment, however, proves that babies really do imprint on auditory experiences while still in the womb. In this case, mothers were asked to read a particular story aloud, twice a day, during the last six weeks of pregnancy. The story was by Dr. Seuss again, this time The Cat in the Hat, and it was estimated that the babies spent a total of about five hours listening to it in the womb. Shortly after birth, they were tested to see whether they preferred listening to their mothers rea...