You want to get healthier, so you join a gym at $20/month, go three times a week, and burn about 600 kcal on each visit.
Good for you!
But maybe you can do better… with math!
That gym is 5 miles from your home, and you drive the 10 miles (5 there and 5 back) in your 30 mpg car, thus using 1/3 a gallon of gas for the trip. Because gasoline contains about 31,500 kcal per gallon (see here), you’ve just used 10,500 kcal to go to the gym to burn 600 kcal.
You burned 10500 kcal to for a 600 kcal benefit. You’re silly!
If you’re getting 30mpg at 31500kcal/g, then you’re burning (31500/30) 1050 kcal/mile or about 0.6 kcal/yard. Push your car 100 yards and you’d burn 60kcal. Push your car the length of 10 football fields and you’d burn the same 600 kcal you burned at the gym.
So here’s a new plan. Instead of paying the gym each month, driving 5 miles there and 5 miles back 3 times a week, save your money (about $600/year in gym fees, gas cost, and auto depreciation) and instead just push your car a quarter mile down the road (about 5 football fields) and a quarter mile back to your garage. You’ll burn as many calories, save time and money, and I guarantee you’ll get to meet more of your neighbors.
Once again, better living through math.
[[Next week: The McDonald's drive-thru fitness plan.]]