Hillary Clinton suffered a coughing fit lasting over a minute at a Jewish Federation campaign stop in Iowa Monday, raising further questions about her health and stamina during this election season.

Breitbart News led the coverage of Clinton’s slowness during the Democratic debate in New Hampshire in coming back from the women’s restroom during a commercial break. That slowness may have been a flare-up of her post-concussion problems, which have continued to dog her, according to law enforcement sources close to Clinton.

Clinton is still taking a blood thinner medication and daily thyroid pills following her concussion in 2012. She has a medical condition called hypothyroidism, commonly caused by an underactive thyroid, which could diminish her energy levels.

Additionally, journalist and author Ed Klein wrote about some details of her health for Breitbart News.

“To this day, Hillary still suffers from many of the troubling symptoms that I wrote about in Unlikeable: blinding headaches, exhaustion, insomnia, and a tremor in her hands. As a precaution against the spectacle of fainting in public, which could easily doom her candidacy, Hillary now travels with a personal physician on all her major campaign trips,” Klein wrote.

“Tension headaches continue to plague her and often make it hard for her to maintain her grueling schedule. Her closest aide, Huma Abedin, confessed in an e-mail that Hillary is easily “confused”; Huma frequently orders campaign aides to alter Hillary’s schedule at the last moment so the candidate can catch her breath and take out time for naps,” Klein wrote.

Clinton is in a deep nose dive in the polls, especially among white voters, and with Democrats in Iowa and New Hampshire.