Being able to walk up four flights of stairs without stopping for a break is key to avoiding an early death, researchers say.
Spanish scientists tested the theory on nearly 13,000 people who were battling or suspected to have coronary artery disease.
They found those who struggled were three times more likely to die from heart disease and faced twice the risk of dying from cancer.
The Emergency Election Sale is now live! Get 30% to 60% off our most popular products today!