![Trail Runner Nation show](https://d3dthqtvwic6y7.cloudfront.net/podcast-covers/000/057/062/small/trail-runner-nation.jpg)
Summary: In this edition of Grab Bag, Alex Hutchinson and Matt Laye join us as we try an find out the truth behind: Over breathing? Can we become so efficient that we are burning less energy than a sedentary person? Is there a benefit to stretching? How does your microbiom affect health? Can smiling improve performance? Do we have limits to the number of calories we can process?