Bernie Sanders, 82, insists he has the energy to run for reelection

• Bernie Sanders is the second-oldest senator, and he wants to serve six more years.
• Despite other older senators struggling with health issues, Sanders is pressing ahead.
• "I would not have run if I didn't think I had the energy," he said.

Bernie Sanders will be 89 in January 2031, the end of what could be his fourth term in the Senate.

That didn't deter the 82-year-old Vermont senator and two-time presidential candidate from announcing his reelection bid last week.