hillary clinton Hillary Clinton leaves an apartment in New York City. AP Photo/Craig Ruttle

Hillary Clinton appeared to stumble when, as her campaign reports, she became overheated at a memorial for the victims of the September 11, 2001 attacks in New York City.

Clinton, it turns out, was recently diagnosed with pneumonia, an infection of the lungs. Business Insider science editor Erin Brodwin explains the common illness in detail here.

It shouldn't surprise anyone that a person with pneumonia, standing outside in a full suit, would have a health episode. But Politico's Glenn Thrush and Brianna Ehley report that a "person in her orbit" said it's difficult to convince Clinton to drink enough water as she goes about her busy day. "The real issue is chronic dehydration, exacerbated by her lung problem," they wrote.

If Clinton indeed does not enjoy drinking water, she might be pleased to learn that there are a number of drinks at least as hydrating as water.

A March study in the American Journal of Clinical Nutrition examined the impacts of 13 drinks on subjects' hydration levels two hours after consuming them.

This chart lays out the results:

hydration American Journal of Clinical Nutrition

The key takeaway: Several drinks, including orange juice, full-fat, and skim milk are more hydrating over a span of a couple hours than water. The researchers suggest their fats and other nutrients cause them to process more slowly through the stomach, causing their fluids to remain in your body longer.

An important caveat: This study is only definitive for relatively small amounts consumed over short periods. While lagers and coffees seem to produce similar results over a two-hour timespan, we wouldn't recommend trying to subsist long-term on either liquid drug without at least asking your doctor about it first.

But the study drives home an important point. While staying hydrated is critical, and it's wonderful to drink plenty of water — which can hydrate us without any calories or strange artificial sweeteners — plain old water is not the only way to fend off dehydration. Other drinks will do, and even things like raw fruits and vegetables help you stay hydrated throughout the day. Water alone is not the only way.