Polar bears are in danger of extinction in the future if globalwarming continues, as their habitat, Arctic sea ice, is shrinkingevery year, making it difficult for bears to have enough food tolast through the lengthening summers.With a population of nearly 25,000, the polar bear is not in dangerof extinction now.
1 In general, anything that is good for your heart is great for your brain. 2  Aerobic exercise is great for body and brain: not only does it improve brain function, but it also acts as a first aid kit on damaged brain cells.
Beginning exercisers can start with 15-20 minutes of a low intensity activity, like easy walking, three times per week. As your fitness level increases, first increase the duration and then the intensity of your workouts. Here are some of the many benefits of aerobic exercise: