Jonathan Lambert

The updated shot will include several strains that heavily affected the U.S.

during this flu season.

If approved by FDA, the vaccine will be available in the fall.

Jonathan Lambert, NPR News.

Twice a year, scientists from around the world...

cram into a conference room to talk flu.

They go over reams of data collected from 130 countries about how the virus is spreading to design next season's vaccine.

There was some question over whether the U.S.

would participate this year, since the U.S.

says it's now officially out of the WHO.

But the U.S.

is there, at least virtually.

Ali Khan is dean of public health at the University of Nebraska.

Jonathan Lambert, NPR News.

For an athlete to work hard, their muscle cells need oxygen.

The more oxygen they can get, the harder they can go.

Scientists call the maximum amount of oxygen an athlete can use during exercise VO2 max.

Scientists have measured VO2 max across all kinds of athletes, and cross-country skiers consistently rank towards the top.

Steven Seiler, an exercise physiologist at the University of Agder, explains why.

That means their cardiovascular systems are working overtime to fuel all those muscles and fight gravity because they're upright.