U.S. Secretary of State Hillary Rodham Clinton's ailing health is back in the news after the State Department said Saturday that she fainted and sustained a concussion last week after becoming dehydrated from a stomach virus that led her to cancel a trip to Africa and the Persian Gulf.

Clinton is recovering from the injury at home, where she is being monitored by doctors, and is expected to return to her State Department duties "soon," according to a statement by aide Philippe Reines, CBS News reported.

The reports of health woes surrounding Clinton, who is expected to step down from her current post as early as this month, are raising questions about her presidential ambitions.

Although Clinton has not declared she will run for the Democratic presidential nomination in 2016, many political observers have already declared her a shoo-in, and some of her recent activities suggest she is already gearing up for a run.

Clinton came close to winning the 2008 Democratic nod, eventually losing to Barack Obama on the way to his securing the presidency, and the drumbeat for her to run for the 2016 nomination is already loud and insistent.

Maureen Dowd wrote recently in the New York Times that Clinton seems already to be showing signs of being more focused on her future as a presidential candidate than on her duties as secretary of state.

Dowd suggested that Clinton's tepid remarks at the Brookings Institution's Saban Forum a couple of weeks back -- when she failed to forcefully condemn Israeli Prime Minister Benjamin "Bibi" Netanyahu following the announcement of a new, highly controversial move by Israel to take steps toward building settlements -- show she is already planning for the 2016 campaign.

"She didn’t whack Bibi, as he deserved. Many there came away assuming that it was the beginning of Hillary’s 2016 campaign, that she was thinking about her future rather than her present," Dowd wrote, adding, "Far from being depleted and ready for a spa, she’s energetically rounding up the usual suspects."

As the commentariat continues to discuss the supposed inevitability of her running for, and winning, the 2016 nomination, some political types are growing worried that the 65-year-old's health could put a monkey wrench in those plans. If she were to win the 2016 election, she would start her term at the age of 69, which some say makes her a risky choice for president.

For instance, ABC's Barbara Walters flat-out asked Clinton this month whether her age will be "a concern" if she decides to run for president, voicing a question many have quietly asked in recent weeks, as noted by the Examiner.

Clinton, in answer, played down the question about her age being "a concern." She told Walters: "It really isn’t. I am -- thankfully, knock on wood -- not only healthy but have incredible stamina and energy. I just want to see what else is out there."

However, the headlines first about the stomach virus that caused the globe-trotting diplomat to cancel her overseas trip, and now about her fainting and suffering a concussion as a result of dehydration related to that illness, are making the worries about her advanced age seem a little more immediate.

Although there are no reports that she has any major chronic illnesses such as cancer, seeing reports about her ill health put questions in the minds of many who are beginning to track the 2016 election.

And some say her grueling schedule could be wearing her down, as she has visited 112 countries during her time at the State Department, the most of any secretary of state in American history. That doesn't bode well, they say, for the former U.S. senator from New York being prepared to take on the most stressful job in American politics by occupying the White House.

Clinton spoke to the overwhelming nature of her current position when she told Walters that she wants to "kick back" after her exhausting run at State, as pointed out by the Daily Mail. "Being on planes ... as much as I am, takes something out of anybody, doesn't matter how old you are or how often you've done it," she said.

And, despite the ongoing cheerleading by Democrats hoping she will run in 2016, Clinton also told Walters that she doesn't plan to do so, as reported by Reuters. "I've said I really don't believe that that's something I will do again. I am so grateful I had the experience of doing it before."

The Senate Foreign Relations Committee -- chaired by Sen. John Kerry, D-Mass., who has reportedly been selected by Obama to replace Clinton -- and the House of Representatives Foreign Affairs Committee said that because of her current medical status, Clinton will not speak at Thursday hearings on the Sept. 11 attack on the U.S. consulate in Benghazi, Libya, during which four Americans, including U.S. Ambassador J. Christopher Stevens, were killed, the Associated Press reported.