In this episode, Todd Bumgardner re-answers a question because he just didn't think he did a good enough job the first time around. He covers why some folks manage exercising at a high heart rate even when it seems like they shouldn't be able to. He also explains some basics about human energy physiology and conditioning energy systems.

Click the link to download a FREE copy of our most popular training manual, 5 Biggest Backcountry Training Mistakes: And How to Avoid Them