1 00:00:00,079 --> 00:00:03,883 So recently, I went into my doctor's office, 2 00:00:03,883 --> 00:00:05,598 and I was told that my blood pressure 3 00:00:05,598 --> 00:00:08,563 was 115 over 75. 4 00:00:09,410 --> 00:00:11,627 So I thought we would talk about exactly what this means 5 00:00:11,627 --> 00:00:12,998 and trying to figure out 6 00:00:12,998 --> 00:00:15,068 how to think about blood pressure in general, 7 00:00:15,068 --> 00:00:17,824 using these numbers and this experience 8 00:00:17,824 --> 00:00:20,066 as kind of a launching point. 9 00:00:20,451 --> 00:00:22,667 So, the way I think about blood pressure is, 10 00:00:22,667 --> 00:00:25,880 I always imagine a kind of tube, 11 00:00:26,265 --> 00:00:28,140 and I imagine blood going through that tube. 12 00:00:28,140 --> 00:00:30,399 And this tube is like a blood vessel. 13 00:00:30,399 --> 00:00:32,681 So, there is blood trying to get its way 14 00:00:32,681 --> 00:00:34,432 from one side to the other. 15 00:00:34,740 --> 00:00:39,564 And on its way, the kind of neat thing that it's doing 16 00:00:39,564 --> 00:00:42,702 is, as it flows, it's pushing out. 17 00:00:42,702 --> 00:00:47,072 So it's forcing against these walls. 18 00:00:47,979 --> 00:00:50,444 And, specifically what I mean by that, 19 00:00:50,444 --> 00:00:53,100 there's cells and there's plasma, 20 00:00:53,100 --> 00:00:56,030 and all that stuff is pushing out against the walls 21 00:00:56,030 --> 00:00:57,281 of the blood vessel. 22 00:00:57,281 --> 00:00:59,909 So you've got a force, 23 00:01:00,863 --> 00:01:03,303 and that force is being exerted 24 00:01:03,303 --> 00:01:06,728 on the surface area of the blood vessel. 25 00:01:06,728 --> 00:01:09,252 So it's force over a surface area, 26 00:01:09,252 --> 00:01:12,511 and anytime you see a force over an area, 27 00:01:12,511 --> 00:01:14,613 you know that equals a pressure. 28 00:01:14,613 --> 00:01:16,142 And in this case it's a blood pressure, 29 00:01:16,142 --> 00:01:18,795 because it's the blood that's doing that work. 30 00:01:19,364 --> 00:01:21,997 So, this is how I think of blood pressure, 31 00:01:21,997 --> 00:01:24,401 specifically those little blue arrows. 32 00:01:24,401 --> 00:01:27,041 And the two questions that pop into my mind 33 00:01:27,041 --> 00:01:30,521 any time I'm thinking about blood pressure, 34 00:01:30,521 --> 00:01:35,412 are where is the blood pressure being taken, 35 00:01:35,412 --> 00:01:37,216 and when are you taking it? 36 00:01:37,216 --> 00:01:40,110 So, let's start with the first question: where? 37 00:01:40,110 --> 00:01:44,071 And by that I mean, where in the circulatory system? 38 00:01:44,071 --> 00:01:45,993 So you've got the heart. 39 00:01:45,993 --> 00:01:47,985 And it's my Valentine's Day heart. 40 00:01:47,985 --> 00:01:51,085 And you got the aorta coming of off the heart, 41 00:01:51,085 --> 00:01:52,991 and it's got lots of branches, 42 00:01:52,991 --> 00:01:55,486 but I'm going to just draw one branch, 43 00:01:55,486 --> 00:01:58,659 which is the artery leading off to my arms. 44 00:01:58,659 --> 00:02:01,478 This is called the brachial artery. 45 00:02:01,478 --> 00:02:03,275 Going off to my arm. 46 00:02:03,275 --> 00:02:05,931 And usually, let's say 90% of the time, 47 00:02:05,931 --> 00:02:07,555 maybe even more, 48 00:02:07,555 --> 00:02:09,183 the blood pressure that you're getting recorded, 49 00:02:09,183 --> 00:02:10,926 or the number that is being told to you, 50 00:02:10,926 --> 00:02:13,915 is being checked at this point. 51 00:02:13,915 --> 00:02:15,582 I marked it with a little x 52 00:02:15,582 --> 00:02:17,602 because that's kind of the upper arm. 53 00:02:17,602 --> 00:02:19,759 So that's usually where they're checking the blood pressure. 54 00:02:19,759 --> 00:02:22,003 And again, they're checking the force 55 00:02:22,003 --> 00:02:24,922 that the blood is putting on the vessel walls. 56 00:02:24,922 --> 00:02:27,239 These little blue arrows. 57 00:02:27,500 --> 00:02:29,326 So that answers the 'where' question. 58 00:02:29,326 --> 00:02:30,732 And certainly you can imagine, 59 00:02:30,732 --> 00:02:33,349 if I'd check blood pressure at some other spot, 60 00:02:33,349 --> 00:02:36,999 let's say over here, or over here, 61 00:02:36,999 --> 00:02:40,051 you know, you might get a different blood pressure reading 62 00:02:40,051 --> 00:02:41,876 than if I check it at the yellow x. 63 00:02:41,876 --> 00:02:45,492 So really, we're just talking about that one spot. 64 00:02:45,492 --> 00:02:48,000 Now the other question is, when are you checking it? 65 00:02:48,000 --> 00:02:51,543 So for this, let me show you a little table, 66 00:02:51,543 --> 00:02:53,053 or a figure of it. 67 00:02:53,053 --> 00:02:55,827 So imagine that over time, 68 00:02:55,827 --> 00:02:57,686 time is this way, 69 00:02:57,686 --> 00:02:59,770 you have different recordings for blood pressure. 70 00:02:59,770 --> 00:03:02,295 So this will be blood pressure. 71 00:03:03,018 --> 00:03:05,165 And blood pressure is usually measured 72 00:03:05,165 --> 00:03:07,196 in millimeters of mercury. 73 00:03:07,196 --> 00:03:09,962 So I'll write mm of mercury here. 74 00:03:10,301 --> 00:03:12,400 And let's go from 200 75 00:03:12,400 --> 00:03:14,837 all the way down to 0. 76 00:03:15,267 --> 00:03:17,511 And I'll use my numbers, 77 00:03:17,511 --> 00:03:19,825 that I got from the doctor the other day, 78 00:03:19,825 --> 00:03:21,546 to illustrate what I'm trying to say. 79 00:03:21,546 --> 00:03:25,286 So, right at that x, that yellow x, 80 00:03:25,286 --> 00:03:29,146 at the bottom, let's say, of my reading, I got 75. 81 00:03:29,146 --> 00:03:32,536 So let's start at 75, which is about here. 82 00:03:32,859 --> 00:03:35,554 As the heart is pumping, 83 00:03:35,554 --> 00:03:37,348 the pressure starts building up. 84 00:03:37,348 --> 00:03:40,837 And it gets up to about 115. 85 00:03:40,837 --> 00:03:42,836 So really, what is happening is, 86 00:03:42,836 --> 00:03:45,242 blood is making its way from the heart, 87 00:03:45,242 --> 00:03:48,368 as it squeezes, towards that x. 88 00:03:48,368 --> 00:03:51,013 And as it gets there, the force 89 00:03:51,013 --> 00:03:53,699 that it's putting on the walls is going up, up, up. 90 00:03:53,699 --> 00:03:58,237 And it goes from 75 all the way to 115. 91 00:03:58,237 --> 00:04:01,856 So that all happens during the squeezing part 92 00:04:01,856 --> 00:04:03,345 of the heart cycle. 93 00:04:03,345 --> 00:04:04,957 We call that systole. 94 00:04:05,326 --> 00:04:07,277 So this is all happening during systole, 95 00:04:07,277 --> 00:04:09,061 which is when the heart is squeezing down. 96 00:04:09,061 --> 00:04:11,288 And we know the heart is a pump. 97 00:04:12,318 --> 00:04:14,922 Now from that point forward, 98 00:04:14,922 --> 00:04:16,856 the heart begins to relax. 99 00:04:16,856 --> 00:04:20,644 So at this point, at 115, the heart is now relaxing slowly. 100 00:04:20,644 --> 00:04:23,903 And as it relaxes, the pressure begins to fall. 101 00:04:23,903 --> 00:04:27,765 And it continues to fall all the way up here. 102 00:04:27,765 --> 00:04:31,368 And the pressure gets down to about 75 again. 103 00:04:31,368 --> 00:04:32,989 And this is diastole. 104 00:04:32,989 --> 00:04:35,099 So this is when the heart is actually 105 00:04:35,099 --> 00:04:38,670 taking a break from squeezing, and is now refilling. 106 00:04:38,670 --> 00:04:40,618 And we call that diastole. 107 00:04:40,618 --> 00:04:42,795 So I'll call that refilling. 108 00:04:47,026 --> 00:04:51,126 And so during systole, you spend about 1/3 of the time. 109 00:04:52,510 --> 00:04:55,530 And in diastole you spend about 2/3 of the time. 110 00:04:55,530 --> 00:04:58,006 And I'm talking about 1 heartbeat here. 111 00:04:58,006 --> 00:05:00,630 So this would be 1 heartbeat. 112 00:05:00,630 --> 00:05:02,782 So it's not 50-50. 113 00:05:02,782 --> 00:05:04,715 And the easy way to remember this is 114 00:05:04,715 --> 00:05:08,290 in a given day, I spend about 8 hours working, 115 00:05:08,290 --> 00:05:11,287 and about 16 hours relaxing, or not working. 116 00:05:11,287 --> 00:05:14,180 So I think of the heart doing its squeezing, its work, 117 00:05:14,180 --> 00:05:16,987 for 8 out of 24, or about a third. 118 00:05:16,987 --> 00:05:20,792 About the same as me. About a third of the time, 119 00:05:20,792 --> 00:05:23,342 the heart is squeezing. 120 00:05:23,342 --> 00:05:26,103 So that's how the heart is spending its time 121 00:05:26,103 --> 00:05:28,058 in systole and diastole. 122 00:05:28,058 --> 00:05:31,071 And the pressure is ranging between 115 and 75. 123 00:05:31,071 --> 00:05:34,590 So really, it never just 115 of just 75. 124 00:05:34,590 --> 00:05:36,640 It's somewhere between the two. 125 00:05:36,640 --> 00:05:39,113 For example, if I check right here in time, 126 00:05:39,113 --> 00:05:44,879 it might be 85, or here it might be 102, or here it might be 87. 127 00:05:44,879 --> 00:05:49,884 So it's somewhere between 115 and 75. 128 00:05:49,884 --> 00:05:53,294 So this number then, this number I wrote up here, 129 00:05:53,294 --> 00:05:54,435 becomes a range. 130 00:05:54,435 --> 00:05:58,795 This is the range of blood pressure. 131 00:05:58,795 --> 00:06:00,635 So when I talk about 'when', it really depends on 132 00:06:00,635 --> 00:06:02,549 where in the cycle you're at. 133 00:06:02,549 --> 00:06:04,552 And you're somewhere in that range. 134 00:06:04,552 --> 00:06:06,363 And when I talk about the 'where', you know we're talking 135 00:06:06,363 --> 00:06:08,925 about a reading that's taken in the upper arm. 136 00:06:08,925 --> 00:06:11,584 So those are the two thoughts that should cross your mind 137 00:06:11,584 --> 00:06:13,590 every time you hear a blood pressure recording. 138 00:06:13,590 --> 00:06:16,178 And of course, the top number, 115, 139 00:06:16,178 --> 00:06:18,081 is the systolic blood pressure. 140 00:06:18,081 --> 00:06:21,156 And 75 is the diastolic blood pressure.