Carrie Underwood is in great shape thanks to her diet and fitness regimen, so why did she need oxygen at a show in Colorado Thursday night?  Carrie posted a picture of herself on Instagram wearing an oxygen mask on her face during the concert.  The caption read, "In high altitudes, they put oxygen in my dressing room under the stage! This is me before the encore."

Carrie's Blown Away tour continues Tuesday night with a show in Billings, MT.

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