1 00:00:00,560 --> 00:00:03,880 Speaker 1: Welcome to Brainstuff from house stuff works dot com where 2 00:00:03,880 --> 00:00:15,080 Speaker 1: smart happens. Hi, I'm Marshall Brain with today's question, how 3 00:00:15,120 --> 00:00:19,520 Speaker 1: do I burn calories on a stair machine? Let's start 4 00:00:19,560 --> 00:00:23,200 Speaker 1: with normal stairs and understand why they burn calories, and 5 00:00:23,200 --> 00:00:25,919 Speaker 1: then we can look at stair machines as a special case. 6 00:00:26,600 --> 00:00:31,000 Speaker 1: The how stuff Works article on how horsepower works explains 7 00:00:31,120 --> 00:00:35,640 Speaker 1: the unit of power known as horsepower. One horse power 8 00:00:36,200 --> 00:00:40,080 Speaker 1: is five hundred fifty foot pounds of work per second. 9 00:00:40,600 --> 00:00:43,720 Speaker 1: If a horse or an engine were to raise a 10 00:00:43,880 --> 00:00:46,559 Speaker 1: five hundred and fifty pound load at a rate of 11 00:00:46,680 --> 00:00:50,120 Speaker 1: one ft per second, it would be exerting one horse 12 00:00:50,159 --> 00:00:53,360 Speaker 1: power of effort. So let's imagine that you're standing at 13 00:00:53,360 --> 00:00:55,840 Speaker 1: the bottom of the Empire State Building in New York 14 00:00:55,960 --> 00:00:59,360 Speaker 1: and you start climbing the stairs. Let's also imagine that 15 00:00:59,400 --> 00:01:03,200 Speaker 1: you a hunder of fifty pounds. If each step raises 16 00:01:03,280 --> 00:01:06,160 Speaker 1: you one foot, and if you walk up the stairs 17 00:01:06,160 --> 00:01:08,959 Speaker 1: at a rate of one step every second, then you 18 00:01:09,000 --> 00:01:12,920 Speaker 1: were doing a hundred fifty foot pounds of work every second, 19 00:01:13,240 --> 00:01:15,919 Speaker 1: or a little more than a quarter of a horse power. 20 00:01:16,240 --> 00:01:18,520 Speaker 1: If you were to run up the steps at a 21 00:01:18,640 --> 00:01:21,479 Speaker 1: rate of four steps every second, you would be doing 22 00:01:21,640 --> 00:01:24,479 Speaker 1: six hundred foot pounds of work every second, or one 23 00:01:24,560 --> 00:01:28,800 Speaker 1: point o nine horsepower. One horse power exerted over an 24 00:01:28,800 --> 00:01:32,400 Speaker 1: hour is equal to six hundred forty one calories. So 25 00:01:32,440 --> 00:01:34,440 Speaker 1: if you were to run up the stairs at a 26 00:01:34,560 --> 00:01:37,520 Speaker 1: rate of five hundred fifty foot pounds of work every 27 00:01:37,560 --> 00:01:40,840 Speaker 1: second for an hour, you would burn off six d 28 00:01:41,000 --> 00:01:44,640 Speaker 1: forty one calories. It's hard for human beings to maintain 29 00:01:44,760 --> 00:01:48,040 Speaker 1: that level of effort for an entire hour. A normal 30 00:01:48,160 --> 00:01:50,559 Speaker 1: human might be able to maintain a rate that burns 31 00:01:50,600 --> 00:01:53,840 Speaker 1: two hundred or three hundred calories per hour, which is 32 00:01:53,960 --> 00:01:56,400 Speaker 1: unfair when you consider that you can gain all that 33 00:01:56,520 --> 00:02:00,280 Speaker 1: back by eating a single candy bar on a stairm sheen. 34 00:02:00,520 --> 00:02:03,600 Speaker 1: It doesn't appear that you're going anywhere, but really you are. 35 00:02:04,160 --> 00:02:07,040 Speaker 1: Imagine that you are climbing a long ladder, but the 36 00:02:07,120 --> 00:02:09,560 Speaker 1: ladder is sinking in the mud as fast as you're 37 00:02:09,600 --> 00:02:12,600 Speaker 1: climbing it. If you were to stop climbing, you would 38 00:02:12,600 --> 00:02:15,760 Speaker 1: sink into the mud too, so you have to keep climbing. 39 00:02:16,080 --> 00:02:18,840 Speaker 1: It would appear that you're going nowhere, but in fact 40 00:02:18,960 --> 00:02:21,800 Speaker 1: you're climbing at the same rate that the ladder is sinking, 41 00:02:22,080 --> 00:02:25,280 Speaker 1: so you are doing work. The lack of movement is 42 00:02:25,280 --> 00:02:28,480 Speaker 1: an illusion. A stair machine creates the same kind of 43 00:02:28,520 --> 00:02:32,040 Speaker 1: illusion as anyone who has used one can tell you 44 00:02:32,040 --> 00:02:36,160 Speaker 1: you are doing work. For more on this and thousands 45 00:02:36,200 --> 00:02:42,480 Speaker 1: of other topics, because it how stuff works dot com. 46 00:02:42,520 --> 00:02:45,440 Speaker 1: Audible dot com is the leading provider of digital audio 47 00:02:45,480 --> 00:02:48,280 Speaker 1: books and spoken word, with over one tho titles to 48 00:02:48,360 --> 00:02:52,320 Speaker 1: choose from. Audible lets you listen to your favorite books anywhere, anytime. 49 00:02:52,560 --> 00:02:55,600 Speaker 1: Go to audible podcast dot com slash stuff brain to 50 00:02:55,639 --> 00:02:57,880 Speaker 1: get a free audio book download of your choice when 51 00:02:57,880 --> 00:02:58,800 Speaker 1: you sign up today.