Just a few minutes of intense exercise a day could have a surprisingly powerful impact on your heart, brain, and lifespan. Credit: Shutterstock As summer approaches, many people try to get back into healthier exercise habits. Most of us already know physical activity is important, but sticking with a routine can still feel challenging, especially when time is limited. Current health recommendations suggest exercising for at least 2.5 hours each week, with 5 hours considered even better. For