How can exercise and P. E help reduce stress?

pumps up your endorphins

Explaination:

Physical activity may help bump up the production of your brain's feel-good neurotransmitters, called endorphins. Although this function is often referred to as a runner's high, any aerobic activity, such as a rousing game of tennis or a nature hike, can contribute to this same feeling

(basically doing anything that involves moving around or being active can help you forget your irritations or struggles)

cognitive activities are mental processes through which we make sense of the world around us or get to know or experience our environment (internal and external). examples of cognitive activities are reasoning, thinking, perceiving, decision-making, listening, observing,etc.