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The importance of breakfast February 7, 2008

Posted by eric22222 in General, Math.

Today, I walked up 119 stairs going from the walkway near the bottom of the hill to the 3rd floor of Ayres hall. I then walked to the very bottom of the hill to the book store, then walked up 40 stairs back to the walkway, then 80 stairs to the altitude of the CSC. How much of my breakfast did I burn from that walk?

We’ll neglect the energy used walking horizontally and the energy used walking down stairs. Only calculating the upstairs walking, here.

ΔE = mgh

Mass times gravity yields weight, so we’ll replace it with my weight in Newtons, about 578. Compared to me, my backpack was pretty light, so we won’t even bother with that. The height traveled will be the number of stairs times the height per stair, generally 7 inches. And I thought those two years of architecture would be a total waste. That distance is meters is 0.1778. So…

ΔE = ~578 N * 0.1778 m * k

…where k is the number of stairs. Now, this morning, I had a bowl of cereal. The serving size is 3/4 cups, but let’s say I had twice that. There are 120 food calories per serving, so 240 food calories come from the cereal. A cup of milk with that adds 130 food calories, for a grand total of 370 food calories. A little research filled a hole in my calculations: a food calorie is equal to an actual kiloCalorie of energy. That’s pretty confusing, calling them such similar things. Anyway. That’s 370000 Calories of energy. Using Google’s nifty calculator feature, we can find that 1 kiloCalorie is equal to 4184 Joules of energy.

So, on my daily hike to class and back, I expend

ΔE = ~578 N * 0.1778 m *199 / (4184 J / kC) = 4.887 kiloCalories

which is only 1.32% of the energy my breakfast gave me. Of course, that’s only the energy expended going up stairs, and it’s assuming a lot of perfect conditions. To really see how much energy I expended, I’d have to count the energy required to walk, open doors, keep my heart beating, produce enzymes and whatnot, and of course, keep by body temperature up. Actually, that last one might be doable… I’d just need to know my surface area, the outside temperature, etc, but I’m not going to bother with it.  This doesn’t take into account the extra 40 stairs I took to get to the bookstore, since I don’t stop by there every day.

Still, shows you how much breakfast will help you out in the morning.



1. MIchael Palka - February 19, 2008

I really like your site it is necessary to have break fast because you are literally breaking the fast.

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