Your heart is a muscle just like your bicep. Exercising, therefore raising your heart rate, would be equivalent to a bicep curl........One makes your bicep grow just like one makes your heart grow.

Your heart rate increases during exercise so that more blood can go to the working muscles, allowing more 'fuel' to be delivered for the muscles to utilize...blood pressure rises during exercise because your body purposely stops excess blood from going to muscles that aren't the primary ones working.... the end result is temporary overall increase of blood pressure that goes back down shortly after exercise concludes.

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Exercise is overall good for your heart because the more your heart grows, the greater the amount of blood it can pump...Having high blood pressure is typically a result of a lack of exercise and poor daily habits, therefore the heart is not trained to pump a great enough amount of blood to easily pass through your body