U.S. Senator Bernie Sanders passed a stress test this month after a heart attack in October.
The heart attack required him to have two stents inserted in an artery, reports Reuters.
Sanders’ campaign released letters from his main doctor and two heart specialists.
All the doctors gave the 78-year-old White House hopeful a clean bill of health.
Sanders’ exercise capacity was average for otherwise healthy men his age with no known heart disease.
Sanders has the support of about 18.9% of voters in the Democratic nominating contest.
Sanders trails former Vice President Joe Biden, who is on 28.3%.