Most everyone has had the experience of feeling lightheaded on occasion. Sometimes it registers as just a passing moment of dizziness. Other times it can feel as if you're about to pass out. But what is really behind that sudden weightless feeling? Why does it occur in the first place?
Lightheadness有很多原因
解释的各种原因，可以引发灯盏花的感觉格雷格福纳诺，MD洛杉矶大学洛杉矶心肌病中心的主任。“如果有情况限制血流到大脑的情况，也可以发生，也可以出于其他原因，”他说。
“灯头的原因包括脱水，过热暴露，延长的站立，体力过度的努力，超快，心脏速度非常缓慢，高血压，来自自主神经系统中的药物或异常的低血压。”
Fonarow博士增加了“瓣膜心脏病，如主动脉狭窄，也可能导致灯光。”但是焦虑和过度通气也可以。他警告说，在最严重的是“灯塔可能是心脏病发作或中风的迹象。”
Lightheadness：心脏病发出警报标志
According to theAmerican Heart Association（aha）除了胸部不适和呼吸急促的经典症状外，虽然可能令人惊讶的心脏病发作是一种壮丽的感觉。
这个怎么可能？由于斑点随着时间的推移而随身携带血液的动脉，可能会发生心脏病发作，这是一种称为动脉粥样硬化的病症AHA。动脉可以从斑块沉积物变得如此缩小，血液流量减少甚至停止。
Equally dangerous, pieces of plaque can break off and become lodged in an artery, completely blocking blood flow, the AHA explains. Depending on the artery involved, you can suffer aheart attack。该plummeting blood flow starves both the heart and other organs of needed oxygen, and that can cause a feeling of lightheadedness.
该AHA补充说，头晕和灯头也可能是延长不规则心跳的症状，称为心律失常。
Read more：锻炼后灯头
Ear Trouble: A Different Type of Culprit
内耳的问题会引起奇怪的感觉,but rather than lightheadedness, the sensations are more often a feeling of weightlessness, which is usually associated with vertigo. However, it may be hard for you to tell the difference between weightlessness and lightheadedness without a doctor's help.
“灯光需要与影响平衡的眩晕来区分，并且是个人或周围环境旋转的感觉，”Fonarow博士说。虽然眩晕可能是由内耳感染引起的，但是另一种类型的内耳病症 - 被称为良性阵发性位置眩晕（BPPV） - 实际上是最常见的原因，根据美国家庭学院（aafp）。
AAFP说，BPPV是耳朵内部耳朵内部的微小钙颗粒的不规则簇。通常这些粒子会告诉你的大脑，方向移动头部。但是，如果他们变得不均匀分布，他们可以过度刺激神经系统，欺骗你的大脑思考你的头已经搬家。好消息：BBPV很容易被诊断和通过一系列头部练习处理，可以帮助再分布粒子。
糖尿病：另一个令人惊讶的触发器
If you have diabetes, it's important to be on the lookout for signs of dizziness and lightheadedness. These are the hallmarks of hypoglycemia, which is when your blood sugar falls too low, below 70 mg/dL, according to the国家糖尿病和消化肾病研究所。低血糖的最常见原因正在跳过一顿饭，错误给药胰岛素和过度行使说Mayo Clinic。
但任何人都可以在某些情况下体验低血糖。一些药物可以引发血糖中的一滴水，因为可以过度饮酒，梅奥诊所指出。
When blood sugar levels drop too low, a rapid spike in adrenaline gets underway, explains the美国糖尿病协会（ADA）。反过来，可以触发各种警告标志，包括动摇，出汗，头痛，烦躁，是的，灯头。
该remedy is quickly downing a high-sugar drink like juice or eating a piece of candy or a glucose tablet, says ADA. This should both right your blood sugar levels and alleviate the dizziness.