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.
Aerobic exercise stimulates the growth of new neurons, also known as neurogenesis through the release of brain-derived neurotopic factors. Endurance exercises release Irisin, a hormone linked to improved cognitive function, fat loss and overall health.
To benefit most from aerobic exercise, you should work out hard enough to raise your heart rate to its training zone (target heart rate) for at least 20 minutes on most days. This enhances your aerobic capacityâthat is, the ability of your cardiovascular system to deliver oxygen to the bodyâs cells during exercise.