Blood pressure: What do the numbers mean and why do they matter?
By Laura Williamson, American Heart Association News
It's a standard part of any medical visit. Someone, typically a nurse, 在你的手臂上缠上一个袖口，让你安静地坐着，当袖口挤压到不舒服的时候, then slowly eases its grip. Some numbers get jotted down in your chart.
"136 over 79."
What does that even mean?
“最上面的数字——收缩压——告诉我们当心脏跳动时，血液对动脉壁的压力有多大," said Dr. Niteesh Choudhry, 他是哈佛医学院的医学教授，也是波士顿布里格姆妇女医院的住院医生. “最下面的数字，也就是所谓的舒张压，是指心脏静止时动脉壁的压力。.
乔杜里说，当任何一个数字长沙巴足球体育平台过高时，“都会导致各种各样的不良后果”. 这可能包括中风、心脏病、肾衰竭和其他慢性疾病. "High blood pressure is a major cardiovascular risk factor, leading to bad outcomes in the heart and brain, and that's why it's gotten so much attention for so long."
Nearly half of U.S. adults have high blood pressure, or hypertension. 因为通常没有症状，如果人们不检查，很多人都不知道自己得了这种病.
What's high?
根据美国心脏协会和美国心脏病学会, 成年人的正常血压是收缩压低于120毫米汞柱，舒张压低于80毫米汞柱. 当收缩压持续达到120-129 mmHg，舒张压低于80 mmHg时，血压升高. 当收缩压持续达到130- 139mmhg或舒张压达到80- 89mmhg时，被认为是1期高血压, 当读数持续达到140毫米汞柱或90毫米汞柱或更高时，即为2期高血压, respectively. 血压读数突然超过180收缩压和/或舒张压120被认为是高血压危重症，需要立即就医.
乔杜里说，大部分注意力都集中在最高值(收缩压)上，因为有更多的研究将其与心血管疾病的不良后果联系起来. "But both numbers matter. If one is high but the other isn't, we use the one that's abnormal."
What happens when numbers stay high?
当血压过高时，动脉就会开始硬化. Elizabeth Jackson, 伯明翰阿拉巴马大学心血管结果和有效性研究项目主任. "They are supposed to be flexible. Think about arteries being like a garden hose. If you push a lot of fluid through and the pressure is high, the hose gets stiff and doesn't work as well."
What causes high blood pressure?
高血压随着沙巴足球体育平台的推移而发展，可能由许多因素引起. Some risk factors can be controlled, while others cannot. 可能影响血压水平的因素包括超重, not getting enough physical activity, eating a poor diet or too much sodium, smoking, or not getting good sleep.
Some people are at greater risk than others, Jackson said.
"African American women in the U.S. have some of the highest rates in the world," she said. Historical and systemic factors play a major role in this statistic.
Increasing age, family history, health conditions such as kidney disease and diabetes, and gender also can affect hypertension risk. Until they reach 64, men are at higher risk than women. That reverses at 65 and beyond.
It's treatable.
乔杜里说，好消息是，高血压是可以治疗的，不管这个数字有多高. The treatment is the same for each.
Making lifestyle changes is the first step, Jackson said. This can include losing weight if needed, becoming more physically active, limiting alcohol consumption, managing stress, quitting smoking if the person smokes and eating a healthier diet.
"Keep processed foods to a minimum," she said. "We know they can be high in sugar and salt. 吃各种各样的水果和蔬菜，让你的盘子五颜六色."
杰克逊说，充足、高质量的睡眠也很重要. 美国心脏协会建议成年人每晚睡7到9个小时，以优化心血管健康, more for children depending on age.
乔杜里说，如果仅仅改变生活方式不起作用，可能还需要药物治疗.
What about low blood pressure?
Low blood pressure is less common but still dangerous, Choudhry said. 当人们过度服用高血压药物时，或者当人们脱水或患有其他疾病时，就会发生这种情况.
Unlike with high blood pressure, people whose blood pressure drops too low will usually feel ill, he said. "They'll get dizzy or lightheaded. The treatment is dependent upon the underlying cause."
但杰克逊说，对一个人来说过低的水平对另一个人来说可能完全没有问题. "It really is tailored to what the person's other conditions are."
她说，如果不定期检查血压，这些疾病都无法治疗. "That's why it's important to know those numbers."