When we're in the pleasures of our youth, the idea that our bodies will change as we grow older is often only a theoretical concept. We know it's going to happen but don't have an idea of what it will look like.

You might smoke in your 20s and still be able to run or play sports. You might put on the dreaded "freshman 15" when you go off to school, but maybe the weight gain doesn't instantly change your life.

Unfortunately, some things you do to your body when you're young have the potential to cause erectile dysfunction (ED) as you age. Statistics as to its prevalence vary, but a common formula cited says 40 percent of men in their 40s, 50 percent of men in their 50s and so on will experience some form of ED. Here, we'll look at five choices "old you" wishes "young you" would make differently.

1. Smoking

Young people who smoke may think they'll just quit down the road and all will be fine, and it might be. However, the damage smoking does to your blood vessels can have long-term effects.

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