In 1943, Seyffarth, who was also one of Sweden's leading cyclists, was badly injured during a dirt-bike race. He did a somersault through the air, hit his head against a concrete pillar and was unconscious for 24 hours.
When the Games began again in 1948 after a twelve-year gap, Seyffarth's 1941 5,000m world record was still in the books. At the St. Moritz Games, his chances for a medal in the 5,000m were severely disrupted when he brushed against a photographer who jumped onto the ice to take a picture. Seyffarth lost precious seconds and ended up in seventh place. Two days later, he made up for his disappointment by winning the 10,000m by 9.7 seconds. He also won a silver medal in the 1,500m.