47 Going Up!-Mid

Going Up! FOCUS Question How does high altitude affect the human body?

上升!高海拔如何影响人体?

Sea-Level Survivors Most people on Earth live at or near sea. level—the level. of the surface of the sea The human body is able to handle the conditions at sea level. The pressure inside our body is balanced with the outside air pressure pushing in on us. Our lungs and red blood cells work well due to the plentiful oxygen in the air near sea level. Things are different up in the atmosphere. If you were suddenly placed atop Mount Everest—the highest place on Earth—you would feel a drop in air pressure. With less air pushing in on you, your face and hands might swell. Oxygen molecules at that altitude are farther apart, so breathing would become more difficult.

海平面幸存者地球上大多数人生活在海边或近海。 阶段的水平。人体能够应付海平面上的环境。 我们体内的压力与外部压在我们身上的气压是平衡的。 我们的肺和红细胞由于海平面附近空气中丰富的氧气而运转良好。 大气层里的情况就不一样了。 如果你突然被置于珠穆朗玛峰——地球上最高的地方——你会感到气压下降。 随着吸入的空气变少，你的脸和手可能会肿起来。 在这个高度，氧分子之间的距离更远，因此呼吸将变得更加困难。

Air Pressure What is air pressure, and how does it change with altitude? Earth's atmosphere is made up of billions upon billions of air molecules, including the oxygen molecules that we breathe. All these molecules stack up and press down on Earth's surface. Air pressure is a measurement of the weight of all those molecules. Moving up from sea level, fewer and fewer air molecules are in the column of air above you. Therefore, the air pressure goes down. With less pressure, air molecules spread out and move farther apart. The greater the altitude the lower the air pressure.

气压是什么?气压如何随高度变化? 地球的大气是由数十亿的空气分子组成的，包括我们呼吸的氧分子。 所有这些分子堆积起来，压在地球表面。 气压是所有这些分子重量的测量。 从海平面上升，你上方空气柱中的空气分子越来越少。 因此，气压下降。 在压力较小的情况下，空气分子会扩散开来，离得更远。 海拔越高，气压越低。

High-Altitude Side Effects For most people, exposure to high altitude causes problems. Their feet and hands swell. People breathe faster and more deeply to get more oxygen into their lungs. Because they are not getting enough oxygen, people may feel tired. It may also be harder to fall asleep and hard to wake up. Since there is less moisture in the air at high altitude, it is easy to become dehydrated. At high altitude, people exhale, sweat, and urinate more So their bodies lose even more moisture. Finally, people may suffer from altitude sickness. This means they may vomit, get headaches, or feel as though they have the flu. So how do people safely climb to high altitudes? Math Moment Using the diagram answer this question: At what altitude is the air pressure about half the air pressure at sea level?

高海拔的副作用对大多数人来说，暴露在高海拔会引起问题。 他们的脚和手肿胀。 人们呼吸得更快更深，以便让更多的氧气进入肺部。 因为他们没有得到足够的氧气，人们可能会感到疲劳。 入睡和醒来也会变得更加困难。 由于高海拔地区空气中的水分较少，所以很容易脱水。 在高海拔地区，人们会更多地呼气、出汗和排尿，所以他们的身体会失去更多的水分。 最后，人们可能会患上高原反应。 这意味着他们可能会呕吐、头痛或感觉像得了流感。 那么，人们如何安全地攀登到高海拔地区呢? 数学时刻用图表回答这个问题:在什么高度气压大约是海平面气压的一半?

Climbing Into Thin Air Climbing mountains can be safe and fun! It's important to bring lots of water while hiking in the mountains. People lose twice the moisture at 1,828 meters (6,000 ft.) as they do at sea level. Many climbers also carry bottled oxygen with them when hiking at very high altitude. They spend just a short time at the top of a tall mountain to avoid getting sick. Gradually adjusting to altitude can also help climbers. Each time a person climbs to a higher altitude, he or she rests for at least a day. The body has time to adjust to the new conditions. This process is called acclimatization. Given time, the body can even make more red blood cells than usual to help carry oxygen.

爬山既安全又有趣!登山时带大量的水是很重要的。 人们在海拔1828米(6000英尺)处流失的水分是在海平面上的两倍。 许多登山者在高海拔徒步旅行时也会随身携带瓶装氧气。 为了避免生病，他们只在高山上呆了很短的时间。 逐渐适应海拔高度对登山者也有帮助。 每当一个人爬到更高的海拔，他或她至少休息一天。 身体有时间来适应新的环境。 这个过程叫做适应环境。 随着时间的推移，身体甚至可以产生比平时更多的红细胞来帮助输送氧气。

High-Altitude Humans Some people have an easier time at high altitude. Their bodies have special adaptations to the lower air pressure. People in Tibet have been living in high mountains longer than any group of people on Earth. They have larger lungs than people at sea level. Larger lungs help them take in more oxygen. Some people in East Africa also live at high altitude. Their bodies make more red blood cells to carry more oxygen throughout their body. With larger lungs, they can also take in more air with each breath than people who live at sea level. Do You Know? In part because they live at high altitude, some East African people are amazing long- distance runners Lelisa Desisa is from Ethiopia. He won the Boston Marathon in 2015.

有些人在高海拔地区生活得更轻松。 它们的身体对低气压有特殊的适应能力。 西藏人在高山中生活的时间比地球上任何民族都长。 他们的肺比海平面上的人要大。 更大的肺有助于他们吸收更多的氧气。 东非的一些人也生活在高海拔地区。 他们的身体会产生更多的红细胞，在全身携带更多的氧气。 他们的肺更大，每次呼吸能比生活在海平面上的人吸入更多的空气。 你知道吗?部分是因为他们生活在高海拔地区，一些东非人是惊人的长跑运动员。 2015年，他赢得了波士顿马拉松赛冠军。