If you want to be a runner...
Let’s say that, for some reason, you’ve decided to try running a marathon. Once you kick up your workout routine -- we’re talking two hours or more of intense exercise -- Clark has a different approach. "At this level of exertion, really anything beyond one and a half hours, a sports drink is a good choice, because you’re replenishing both water and nutrients."
Jacque Crockford, an exercise physiologist and education specialist with the American Council on Exercise (ACE), agrees, noting that the 90- to 120-minute mark signals a need for replacement of electrolytes and carbohydrates, both of which you can find in sports drinks. The electrolytes will replenish sodium loss, while carbohydrates are meant to refuel.
Crockford also recommends reaching for a handful of mixed nuts or pretzels or salty pickles for sodium replacement. Additionally, you should be refueling during the workout, not just afterwards.