NORWALK - The first major faceoff between Donald Trump and Hillary Clinton will take place tonight on Long Island.

The presidential hopefuls are scheduled to debate at Hofstra University on Long Island.

While most will focus on what the candidates say, some are just as concerned with how they say it. Some experts believe that body language could be as important as what the candidates say.

Richard Nixon sweating profusely lost him credibility on TV in 1960 against the calm, collected John F. Kennedy. Al Gore also made an impact when he sighed during a debate in 2000.

Experts say Donald Trump needs to look and act presidential. He'll have to balance that with the off-the-cuff brand that shot him to the GOP nomination. As for Hillary Clinton, experts say she needs to appear strong, yet trustworthy.

Experts say this debate could have Super Bowl-level ratings tonight.