Researchers study ultra-athletes competing in Montane Yukon Arctic Ultra
As extreme cold temperatures continue, more racers in the Montane Yukon Arctic Ultra drop out. The few athletes pushing on have a team of German researchers monitoring their every move. Cheryl Kawaja has more.
1:25
1:57
1:48
2:19
2:00
1:37
1:08
2:57
2:21
2:01
