Fight or Flight Fitness

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Alex Hutchinson, over at Sweat Science, when discussing the article that came out (and covered by many blogs) about the optimal running pace, asked a question I have found interesting for a while:

Well, I’ve often pondered the scenario where you’re stranded in the desert with no food, 100 miles from the nearest aid, and you have to decide what your strategy is. Do you run? Walk? How fast? Seems like if you know your optimal pace, you can maximize your odds…

This same question is part of the impetus for this blog. Can a human travel by food 100 miles without food, without food and water? And since biking is 4-6 times more efficient what about traveling 500 or so miles by bike without food (and/or water)?

I have searched around and haven’t come across any mention of anyone having accomplished or even tried these tasks. No doubt our ancient (maybe not so ancient) relatives were faced with having to travel a 100 or so miles without food.

Now maybe most people would think it is impossible to travel 100 miles without consuming any calories - but I guess we won’t know until somebody is willing to try.

We do have enough energy in our fat stores for 11 days of walking or 3 days of running (on average).

Are you up to the challenge?

(H/T to Andrew)

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When you think about survival fitness, or just the ability to complete a marathon or an ironman you need to become aware of how much energy storage you have and of what type. And maybe more importantly how far these energy stores could take you if you are performing a low level task such as walking or a higher energy task such as running.

I won’t discuss the energy system that are the main contributors to events that last less than 1 or 2 minutes, but instead concentrate on the ‘endurance’ energy systems.

glucose and glycogen stores:

——————————————————————–Provides energy for:

—————————————————————————-walking                     running

blood glucose:                            20 g                 15 min                       4 min

liver glycogen:                             80 g                 1 hour                      18 min

muscle glycogen:                    350-700 g         5 - 10 hours             2 - 3 hours

Adipose tissue (fat)           9,000 - 15,000 g        11 days                     3 days

So you can see even if you add up all the glucose/glycogen stores that come from consuming carbs you don’t have enough for completing a marathon in a time that most people are capable of. Most people will complete a marathon in  2.5 to 5 hours and a major part of ‘hitting the wall’ is when you run out of glycogen muscle storage. And obviously any longer events such as ultramarathons, hiking, or ironman events you require fat burning - and you better be good at it.

Despite this fact there are not many of the sport trainers telling you about the importance of the ability to use fat or that this can be trained. If you want to be able to perform well in long endurance events, do a long hike (be it for pleasure or to survive) you want to become an efficient fat burner. Additionally, this might help you lose fat, which is of prime importance for many people.