Hearing a distinct, rhythmic thumping sound in the ear, especially when the environment is quiet, is a common phenomenon. This sound is often synchronized with your heartbeat and becomes more noticeable when resting or lying down. This sensation is the sound of your own internal body processes, specifically the flow of blood, being registered by the ear’s delicate structures.
What is Pulsatile Tinnitus
The perception of a rhythmic sound that pulses in time with your heart is medically defined as pulsatile tinnitus. This differs significantly from the more common form of tinnitus, which is typically described as a continuous ringing, buzzing, or hissing sound that is not synchronized with any body rhythm. Non-pulsatile tinnitus often arises from damage to the tiny hair cells in the inner ear, leading to a misfiring of electrical signals to the brain.
Pulsatile tinnitus, by contrast, is not an electrical malfunction but a physical sound, essentially an internal whooshing or throbbing noise. The sound is generated by the flow of blood through the arteries and veins located near the ear.
When this blood flow becomes turbulent or amplified, the vibrations are transmitted through the bone and tissue to the cochlea, which is the hearing organ. In a sense, the ear is acting like a microphone, picking up the noise of blood pulsing through vessels like the carotid artery and jugular vein, which are situated close to the middle and inner ear.
This means that for many people, pulsatile tinnitus is considered “objective,” meaning a medical professional can sometimes hear the sound with a stethoscope placed over the neck or skull. Finding the specific source of the sound is more likely with this type of tinnitus than with the more common, non-pulsatile form.
The Role of Position and Blood Flow
The reason this sound often becomes louder when lying down is due to a combination of physical and environmental factors. When you transition from an upright posture to a horizontal one, the patterns of blood flow change throughout the body, including the vessels in the head and neck. Gravity no longer pulls blood down toward the feet, resulting in a slightly increased volume and pressure of blood flow to the head, which can amplify the existing sound of blood movement.
Furthermore, the act of lying down often results in the head being placed against a pillow or mattress, which creates an “occlusion effect.” This physical contact blocks out external ambient noise, which normally masks the internal body sounds. By eliminating the distractions of the daytime environment, the internal thumping of blood flow becomes significantly more noticeable to the auditory system.
The change in head position can also affect pressure within the skull, known as intracranial pressure, which naturally tends to increase when lying flat. This increased pressure can influence the nearby blood vessels, further contributing to the audibility of the pulsations. For some, simply elevating the head with extra pillows can reduce this effect and lessen the perceived sound.
Common Reasons for Audible Pulsations
The underlying cause of pulsatile tinnitus is usually related to a change in the speed or smoothness of blood flow through vessels near the ear. These causes are broadly categorized into those that increase the overall rate of blood flow and those that create localized turbulence or structural abnormalities. Conditions that increase the speed of circulation system-wide include severe anemia and hyperthyroidism.
Other common causes involve the narrowing or stiffening of blood vessels, which forces the blood to move turbulently, creating a whooshing sound. Atherosclerosis, or the buildup of plaque in the arteries, can narrow the carotid arteries in the neck, causing a rough, audible flow.
Specific structural issues near the brain and ear can also be the source of the sound, such as idiopathic intracranial hypertension (IIH). This condition involves elevated pressure of the cerebrospinal fluid surrounding the brain, which can compress and affect the large veins that drain blood from the head. This compression can lead to venous sinus stenosis, a narrowing of the venous drainage system, creating a turbulent sound that is picked up by the ear.
Conductive hearing loss, caused by issues like excessive earwax or fluid buildup in the middle ear, can also make internal sounds more prominent. In these cases, the outer or middle ear is less efficient at letting outside sounds in, which means the internal body sounds, including the pulse, are no longer masked and become much louder.
It is important to seek a medical evaluation for pulsatile tinnitus because, while often harmless, it can signal a serious underlying vascular condition. Consult a healthcare provider if the sound is sudden, persistent, or accompanied by other symptoms, such as vision changes, headaches, or dizziness. Diagnosis often requires specialized imaging tests, like Magnetic Resonance Angiography (MRA) or Computed Tomography Angiography (CTA), to visualize the blood vessels and identify the source of the turbulent flow.