Dizziness is a word that is often used to describe two different feelings. 眩晕是一个词往往是用来形容两种不同的感情。 It is important to know exactly what you mean when you say "I feel dizzy" because it can help you and your health professional narrow down the list of possible problems.重要的是要知道到底出了什么你的意思是当你说： “我感觉头昏眼花” ，因为它可以帮助你和你的卫生专业缩小的名单可能发生的问题。

• Lightheadedness is a feeling that you are about to faint or "pass out."头昏是一种感觉，您要微弱或“运出。 ” Although you may feel dizzy, you do not feel as though you or your surroundings are moving.虽然你可能会感到头晕，您不觉得您或您周围的感动。 Lightheadedness often goes away or improves when you lie down.头昏往往消失或改善当你躺下。 If lightheadedness gets worse, it can lead to a feeling of almost fainting or a fainting spell (syncope).如果头昏得到糟糕的是，它可以导致一种感觉几乎昏厥或晕眩（晕厥） 。 You may sometimes feel nauseated or vomit when you are lightheaded.你可能有时会感到恶心或呕吐时，头昏。
• Vertigo is a feeling that you or your surroundings are moving when there is no actual movement.眩晕症是一种感觉，您或您周围正在如果没有实际行动。 You may feel as though you are spinning, whirling, falling, or tilting.你可能会觉得好像你是纺纱，旋转下降，或倾斜。 When you have severe vertigo, you may feel very nauseated or vomit.当你有严重的眩晕，您可能会觉得很恶心或呕吐。 You may have trouble walking or standing, and you may lose your balance and fall.您可能无法走路或站立，和您可能会失去平衡和下降。

Lightheadedness头昏

It is common to feel lightheaded from time to time.这是共同的感觉头昏不时。 Lightheadedness usually is not caused by a serious problem.头昏通常是不会造成的一个严重问题。 It often is caused by a momentary drop in blood pressure and blood flow to your head that occurs when you get up too quickly from a seated or lying position (orthostatic hypotension).它往往是造成短暂下降，血压和血流量，以你的脑袋发生当您起床太快从坐或卧位（体位性低血压） 。

Lightheadedness has many causes, including:头昏有许多原因，其中包括：

• Allergies.过敏。
• Illnesses such as the flu or colds.疾病，如感冒或感冒。 Home treatment of your flu and cold symptoms usually will relieve lightheadedness.家庭治疗的流感和感冒的症状通常会减轻头昏。
• Vomiting, diarrhea, fevers, and other illnesses that cause dehydration.呕吐，腹泻，发烧，和其他疾病，造成脱水。
• Very deep or rapid breathing (hyperventilation).非常深刻或迅速呼吸（过度换气） 。
• Anxiety and stress.焦虑和压力。
• The use of tobacco, alcohol, or illegal drugs.使用烟草，酒精，或非法毒品。

A more serious cause of lightheadedness is bleeding.更严重的头昏是出血。 Most of the time, the location of the bleeding and the need to seek medical care are obvious.大多数时候，位置的出血，需要寻求医疗照顾是显而易见的。 However, sometimes bleeding is not obvious (occult bleeding).然而，有时出血并不明显（隐性出血） 。 You may have small amounts of bleeding in your digestive tract您可能需要少量的出血在您的消化道 over days or weeks without noticing the bleeding.在数天或数周没有发现出血。 When this happens, lightheadedness and fatigue may be the first noticeable symptoms that you are losing blood.在这种情况下，头昏和疲劳可能是第一个明显的症状，你正在失去血液。 Heavy menstrual bleeding also can cause this type of lightheadedness.重工业月经出血，还可导致这种类型的点燃。

An uncommon cause of lightheadedness is an abnormal heart rhythm (arrhythmia), which can cause fainting spells (syncope).一种罕见的原因头昏是不正常的心律不齐（心律失常） ，可引起昏厥魔法（晕厥） 。 Unexplained fainting spells need to be evaluated by a health professional.不明原因昏厥规定需要进行评估的卫生专业。 To check your heart rate, see taking a pulse要检查您的心率，见一个脉冲 . 。

Many prescription and nonprescription medicines can cause lightheadedness or vertigo.许多处方药和非处方药品可引起头昏或眩晕。 The degree of lightheadedness or vertigo that a medicine causes will vary.程度的头昏或眩晕，一个医学原因会有所不同。

Vertigo眩晕

Vertigo occurs when there is conflict between the signals sent to the brain by various balance- and position-sensing systems of the body.出现眩晕有冲突之间的信号传送到大脑的各种平衡和位置传感系统的机构。 Your brain uses input from four sensory systems to maintain your sense of balance and orientation to your surroundings.你的大脑使用的投入从四个感官系统，以保持你的平衡和方向，周围的环境。

• Vision gives you information about your position and motion in relationship to the rest of the world. 视觉让您了解您的位置和运动的关系，世界其他地区。 This is an important part of the balance mechanism and often overrides information from the other balance-sensing systems.这是一个重要组成部分的平衡机制和覆盖的信息往往来自其他平衡的传感系统。
• Sensory nerves in your joints allow your brain to keep track of the position of your legs, arms, and torso. 感觉神经在您的关节让你的大脑来跟踪的立场，您的腿，胳膊和躯干。 Your body is then automatically able to make tiny changes in posture that help you maintain your balance (proprioception).你的身体，然后自动能够作出微小的改变姿势，可以帮助您维护您的余额（本体） 。
• Skin pressure sensation gives you information about your body's position and motion in relationship to gravity. 皮肤压力的感觉让您了解您的身体的位置和运动的关系的严重性。
• A portion of the inner ear部分内耳 , called the labyrinth, which includes the semicircular canals, contains specialized cells that detect motion and changes in position.被称为迷宫，其中包括半规管，载有专门的细胞，能侦测运动和变化的立场。 Injury to or diseases of the inner ear can send false signals to the brain indicating that the balance mechanism of the inner ear (labyrinth) detects motion.损伤或疾病内耳可以发送虚假的信号，表明大脑的平衡机制，内耳（迷路）检测议案。 If these false signals conflict with signals from the other balance and positioning centers of the body, vertigo may occur.如果这些假信号冲突的信号，其他的平衡和定位中心的机构，可能会出现眩晕。