The question of age is nothing new for presidential campaigns. Many question whether Joe Biden's gaffes are a result of his age. The 76-year-old is two years younger than Bernie Sanders, who underwent a heart procedure Tuesday night. The health issue interrupts his campaign and some say it will have a bigger impact on public perception.

"This is terrible news for his campaign and particularly given that yesterday he had such good news," Eric Herzik, University of Nevada Professor of Political Science said. "He was the leading fundraiser for the quarter among democrats. This raises all kinds of questions and he can talk about how vibrant he is and be back on the campaign but if he just had a procedure, I don't think he is going to be as vibrant."

Five of the 2020 presidential candidates are in their 70's. They include President Trump (73) and his republican opponent Bill Weld (75), as well as the three democratic front-runners. Those are Bernie Sanders (78), Joe Biden (76) and Elizabeth Warren (70). Trump is the oldest first-term president. He took office when he was 70 years-old. Their ages could raise more questions as the election nears.

"Presidents and presidential candidates will come out 'I've got this great bill of health and whatnot' because the public, I think rightfully, wants to focus on the viability of their candidate," Herzik said.

A June Economist/YouGov survey shows nearly 40 percent of Americans think presidents in their 70's are too old. The age-old question of age is nothing new. President Reagan was the oldest second-term president at age 73. 

"Reagan turned it around as a joke about "I won't comment on my younger opponent's lack of experience' but he knew it was an issue and he was able to diffuse it," Herzik said.

Democrats are hoping to get new, younger voters. Yet, the front-runners are all older candidates. Voters are split on whether age should play a role in who they vote for.

"I think their decision-making is still, I still trust it, even at an old age as long as the health isn't going to get in the way," Tucker Scozzafava, UNR sophomore said.

"Experience is a factor but I think that your health and the role it plays on the condition of your brain actually contributes to what you would do as president," Abbey Foster, UNR sophomore said.

Some question whether Sanders' heart condition will prevent him from fulfilling his duties, if elected. Herzik says when older candidates are nominated, voters put more emphasis on who the running mate would be.

"The vice presidential choice will get more scrutiny, not just in terms of the classic balancing the ticket or what do you bring to make this ticket stronger but also, 'Gee, you may get called upon,'" Herzik said.

The older democratic candidates is a shift away from the party's traditional candidates. The last five democratic presidents were 55 years old or younger when they took office.

"All of a sudden, the party which is trying to appeal to new voters is bringing out generally older candidates," Herzik said.

Trump and Warren have not faced many questions regarding their ages. That is expected to change as the campaign continues.