[MediaMole]

These really aren’t dangerously cold games. Players are out for a few minutes, then they sit on heated benches with huge propane heaters spewing hot air next to them. Trainers have hot capes waiting on the sidelines.

Even the Packers game was about +5 degrees, not -20. The players had chemical hand warmers and training staff to keep them warm.

[HiTech RedNeck]

Remember the flap over Joe Namath and the panty hose? The panty hose actually did help. Similar hose on the upper body would also help, though likely to get torn up pretty quick in the rough and tumble of a football game.

[castlegreyskull]

I would imagine the range a field goal could be kicked would be reduce 10 or 15 yards, because the ball would feel like your kicking a cement brick.

[Carpe Cerevisi]

Trainers have hot capes waiting on the sidelines.

[Ditto]

"...they sit on heated benches with huge propane heaters spewing hot air next to them. Trainers have hot capes waiting on the sidelines."

Some of the old time coaches like Bud Grant and Chuck Noll didn't even allow sideline heaters, let alone heated benches.