The practice of lowering the head below the level of the heart, often achieved by hanging the head off the side of a bed, is widely discussed online for its purported health and cosmetic benefits. This technique is claimed by some to stimulate circulation and promote various improvements. The core of the practice involves using gravity to momentarily shift the distribution of fluids within the body. A closer examination of the body’s involuntary response to this inverted posture is necessary to understand the actual effects. This analysis explores the immediate physiological changes, evaluates common claims, and addresses the safety concerns associated with this position.
The Physiological Response to Inversion
When the head is inverted below the heart, the body’s circulatory system immediately encounters a significant gravitational shift. This change causes a rapid and substantial increase in venous return, meaning blood flows back toward the head more easily than usual. This influx of blood immediately raises the pressure within the cranial cavity and the eyes.
The body attempts to counteract this sudden pressure increase using its built-in regulatory systems, such as the baroreceptor reflex. This reflex helps regulate blood pressure and heart rate to maintain a stable environment for the brain. However, the mechanical effects of inversion are powerful enough to temporarily overwhelm these controls, causing measurable changes in pressure.
Studies show that in a fully inverted position, mean blood pressure can increase from a normal resting average of about 110/77 mmHg to approximately 130/90 mmHg. Simultaneously, the pressure inside the eyeball, known as intraocular pressure (IOP), also sees a dramatic rise. For healthy individuals, the average standing IOP of around 16 mmHg can surge to between 31 and 34 mmHg during inversion.
This increase in pressure is also reflected in the brain, where intracranial pressure (ICP) rises significantly when the head is positioned lower than the body. The brain’s autoregulatory mechanisms work to maintain constant cerebral blood flow despite this positional change. Increased venous pressure due to gravity is a direct mechanism that contributes to the elevation of ICP.
Common Claims: Appearance and Sensation
The primary claim associated with the inversion method is that the temporary rush of blood to the scalp promotes accelerated hair growth. Proponents suggest that increased blood flow delivers more oxygen and nutrients to the hair follicles, thereby stimulating the growth phase. This theory is often combined with a scalp massage performed while the head is inverted.
The perceived benefits, such as a temporary feeling of skin “glow” or increased alertness, stem directly from the temporary pooling of blood in the face and head. This rush of circulation can cause a temporary redness or flushed appearance, which some users interpret as a cosmetic benefit. The feeling of lightheadedness or a slight pressure sensation is also a direct result of the elevated blood pressure and intracranial pressure.
Despite the widespread anecdotal support, there is currently no rigorous scientific evidence to support the claim that head inversion alone increases the rate of hair growth. While increased circulation to the scalp is beneficial for hair health, the effects of a brief, gravity-induced rush have not been scientifically proven to stimulate long-term growth. The actual positive effect on hair thickness reported by some users is more likely attributed to the scalp massage component of the method, which has been shown to increase hair thickness in some studies.
Safety Concerns and Who Should Avoid It
The rapid and significant pressure changes induced by inverting the head pose several serious health risks, making the practice unsafe for many individuals. The dramatic increase in intraocular pressure (IOP) is particularly concerning for people with pre-existing eye conditions. Individuals diagnosed with glaucoma should avoid head inversion completely, as elevated IOP is a major risk factor for optic nerve damage and progressive vision loss.
The practice is also contraindicated for anyone with high blood pressure or a history of heart conditions. The body’s attempt to manage the rapid increase in blood pressure to the head can strain the cardiovascular system. Similarly, people with a history of stroke, cerebral aneurysms, or any condition involving increased intracranial pressure should not attempt this position.
Other groups who should avoid head inversion include pregnant individuals and those with ear infections or vertigo, as the position can exacerbate dizziness and inner ear pressure issues. For healthy individuals who choose to try the position, the duration must be kept very short, typically no longer than 30 seconds to one minute, to minimize the time spent under elevated pressure. Prolonged inversion increases the risk of headaches, dizziness, and potential injury upon returning to an upright position.