Transcript for Does Nate Silver buy that age will be a major factor in determining the Dem nominee?
Are you concerned at all that this could be in the back of voters' minds, your age and the fact you've had a heart attack now? This may weigh into their decision as to whether they should vote for you? Everything that happens every day weighs on how people feel about you. My own view is that -- I think it's the voters' view. Look at the totality of who a candidate is. The top 12 democratic candidates return to the debate stage Tuesday, including senator Bernie Sanders who has been off the campaign trail since having a heart attack last week. At 78 years old Sanders is the oldest in the field and one of three in their 70s. Will age be a major factor in determining the democratic nominee. We asked Nate silver. Let's start with something easy to prove. The leading Democrats are really old by presidential standards. If elected, Elizabeth Warren would be 71, Joe Biden, 78 and Bernie Sanders 79. Historically 55 is the median age for presidents at inauguration. Of course age doesn't appear to be that big of a concern with the three oldest candidates currently one, two and three in democratic poles. Biden has stayed at the top of the pole all years. Warrens numbers have gone up and Sanders continues to rake in cash from his supporters, many of whom are quite young. There's a difference between Warren and Biden and Sanders. President Reagan was 77 when he finished his second term. Both Biden and Bernie would be older than that on their first day in office. Do voters see a difference between the early 70s and late 70s? They might. One poll earlier this year found 62% of voters had reservations about voting to someone older than 75. That compared to 48% who said they would be less likely to vote for someone over the age of 70. How age plays out is tough to say. If a candidate makes a gaff or has a medical problem, voters may or may not attribute that to age. In polling this week perceptions about whether Sanders could beat trump declined after his heart attack. His standing in the polls is roughly unchanged. One more thing. It may be obvious but it's important to remember that the current president is pretty old too. My bottom line is this, age won't necessarily cause Biden and Bernie's current supporters to abandon them. It may make it hard to expand their coalitions later on.
This transcript has been automatically generated and may not be 100% accurate.