Electronic Cigarette Does It Make You Run Slower? What Are The Side Effects?

My friend has wanted to start smoking i have been smoking for years , he wants to smoke so i said to him to try the e cig , i have only been smoking the e cig for a couple of months now all he wants to know is , will it have any side effects on him , will it make him run slower? have bad lungs ect…?
Thanks in advance.