Have you ever been on a roller coaster and felt your blood rush to your head? Sometimes people feel this sensation even when they aren’t twisting and turning at high speeds — they’re just lying down. Members of MyLupusTeam have described this feeling as a head rush and have asked why this happens.

“I’ll be lying there reading, and it feels like all the blood is rushing to my head. I hear my pulse in my ears and feel pressure in my head, then it’s just gone,” one member said. “Happens twice or three times a day.”

The term “head rush” can also refer to light-headedness caused by a sudden drop in blood pressure, a medical condition known as orthostatic hypotension. Generally, head rush is related to issues with the cardiovascular system.

This article will review five possible causes (besides orthostatic hypotension) of the sensation of blood rushing to your head when you’re lying down.

1. Dehydration

Dehydration — not having enough fluid in your body to carry out normal functions— is a common problem in the United States, particularly among older adults. A headache is often a symptom of dehydration — and a possible culprit for a head-rush sensation.

A headache from dehydration may be mild to severe. The pain can be either throbbing or constant and may get worse if you move your head, such as when bending over. Lying down may initially worsen symptoms and cause a sensation of blood rushing to the head.

If you’re dehydrated, it’s important to drink water slowly to avoid an upset stomach. Resting and drinking water usually improve symptoms — if not, check with your doctor. They can suggest treatment and determine what might be causing your headache.

Also, if you have lupus and think you may be dehydrated, seek medical advice from your rheumatologist. Lupus-related kidney disease, which is called lupus nephritis, can cause excess fluid to build up in your body, and drinking too much water could become life-threatening.

That said, lupus nephritis is typically treated with diuretics (water pills), medications that remove fluid from the body and can cause dehydration. Your rheumatologist will help you manage dehydration safely, taking into account all your medical conditions and medications, as well as your diet, physical activity, and lifestyle. A personalized plan can go a long way toward keeping you hydrated and maintaining your optimal health with lupus.

2. Tension Headache

A type of headache called tension headache also may cause the strange sensation of blood rushing to your head while lying down. Tension headaches are common primary headaches (not caused by an underlying disease), which often affect people with systemic lupus erythematosus, the most common type of lupus.

Tension headaches likely result from a combination of muscular, environmental, genetic, nutritional, and other factors. However, stress and posture play particularly significant roles: Prolonged neck flexion (bending the head forward) stresses the spine, which may cause the shoulders to stoop forward. When this happens, your muscles tighten, and a tension headache could develop.

Typical symptoms of a tension headache include:

• Pain in the scalp, neck, and shoulders
• Dull head pain
• Tightness or pressure in the forehead, sides, or back of the head
• The feeling of a tight band around the head

A tension headache may be triggered by sleeping with your neck in an unusual position. When you’re lying down, the pressure can feel like blood rushing to the head.

If you have occasional tension headaches, over-the-counter pain medication, like ibuprofen or naproxen, will usually treat symptoms. If your headaches occur often, talk with your health care provider about how to manage them — taking pain relievers too frequently can cause more problems.

3. Migraine Headache

A third type of headache, migraine headache, might also make you feel like blood is rushing to your head when you’re on your back. More than 10 percent of the global population have migraine, a condition best known for causing chronic, disabling headache pain. Migraine is more common in women than in men, according to Johns Hopkins Medicine.

Although migraine headaches usually affect just one side, the pain can extend to the entire head, neck, and face. Like dehydration headaches, migraine headaches cause throbbing and pounding that may feel like a rush of blood or a pulsating sensation when you’re lying down.

Unlike tension headaches, migraine headaches typically come with sensitivity to light, noise, and smells. Nausea is also a common symptom, and some migraine headaches are preceded by an aura — a nervous system symptom, such as visual changes, that warns that a migraine headache is about to begin.

Triggers for migraine headaches include:

• Lack of sleep
• Alcohol consumption
• Delayed meals
• Bright lights
• Loud noises (when exposed for a long time)
• Dehydration

If you’re experiencing new migraine symptoms, talk with a health care professional. Treatment usually involves prescription medications along with nutritional and lifestyle adjustments.

4. Idiopathic Intracranial Hypertension

A rare condition called idiopathic intracranial hypertension, which is caused by increased pressure around the brain, could also lead to a head rush. The elevated pressure occurs when, for unknown reasons, cerebrospinal fluid builds up around the spinal cord. The most common symptom is a severe, pulsing headache that may be worse when lying down.

Idiopathic intracranial hypertension can also cause pulsatile tinnitus — a thumping or whooshing sound caused by blood pressure changes in the ear — that is usually one-sided. The combination of pulsatile tinnitus and head pressure may feel like blood is rushing to your head when you lie down.

Increased pressure on the nerves of the eye can cause double vision, another important symptom of idiopathic intracranial hypertension. Treating the condition is important to improve symptoms and prevent vision loss. If you are experiencing symptoms of idiopathic intracranial hypertension, seek immediate medical care.

5. Severe High Blood Pressure

Headache and pulsatile tinnitus can also be caused by severe high blood pressure. Blood pressure is the force of blood against blood vessel walls. Severe high blood pressure, defined as a reading of at least 180 millimeters of mercury (mm Hg) over 120 mm Hg (written as 180/120), raises the risk of heart attack and stroke.

Essential hypertension — high blood pressure not caused by another medical condition — is the most common cause of severely high blood pressure. Half of people with lupus also have high blood pressure (at least 140/90 mm Hg). If you have lupus nephritis, high blood pressure could be related to your condition. Regular follow-ups with your health care provider to get the right treatment — you may need a combination of medications — can help you get high blood pressure under control.

High blood pressure typically causes no symptoms, though some people with severe disease will develop symptoms such as throbbing headaches. Severe high blood pressure can also cause ringing or buzzing in the ears from pulsatile tinnitus, and the sound may be in sync with your pulse. As discussed above, when you’re lying down, the combination of pulsatile tinnitus and a throbbing headache could feel like blood is rushing to your head.

Check In With Your Doctor Promptly

Severe high blood pressure calls for immediate medical evaluation and treatment. In addition, dizziness might rarely be confused with a head rush. If you’re experiencing dizziness, instability, swaying to one side while walking, or ringing in the ears, be sure to have your symptoms evaluated by your health care provider. The sooner you make your doctor aware of new, worsening, or puzzling symptoms, the sooner you can manage them and get relief.

Connect With Others Who Understand

On MyLupusTeam — the social network for people with lupus and their loved ones — more than 223,000 members come together to ask questions, give advice, and share their stories with others who understand life with lupus.

Do you ever feel like blood rushes to your head when you lie down? Do you wonder if other seemingly unusual symptoms might be related to lupus? Share your experience in the comments below, or start a conversation by posting on your Activities page.