In the summer, our body is sweating more because of hot weather, so it becomes even more critical to stay hydrated with this increased water loss, says Samantha Blizzard. "Keeping hydrated is immensely important for more reasons than I could list," says Blizzard, a registered dietitian working for the Atlantic Superstore in Charlottetown and Montague, P.E.I. Water makes up approximately 70 per cent of our body. Our organs need water to function properly, and it helps deliver nutrients to our cells, which is crucial for maintaining optimal energy levels, she explains.