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.
Aerobic exercise is physical exercise of low to high intensity that depends primarily on the aerobic energy-generating process. Aerobic literally means relating to, involving, or requiring free oxygen, and refers to the use of oxygen to adequately meet energy demands during exercise via aerobic metabolism. Generally, light-to-moderate intensity activities that are sufficiently supported by aerobic metabolism can be performed for extended periods of time. When practiced in this way, examples of cardiovascular/aerobic exercise are medium to long distance running/jogging, swimming, cycling, and walking, according to the first extensive research on aerobic exercise, conducted in the 1960s on over 5,000 U.S. Air Force personnel by Dr. Kenneth H. Cooper.