Health

The Benefits of Sensory Deprivation Tank Therapy

Emily Dashiell, ND

Promising information about the benefits of the sensory deprivation tank is emerging from many sources, from clinical research studies to the news. The tank was originally designed in the 1950s, and it quickly became associated with the counterculture of the '60s. Then, it was studied for its health benefits and offered to consumers in the '70s and '80s, after which the tanks became outdated. Today it seems that water-floatation technology is making a comeback. This is perhaps due to the vast sensory overload that many people in modern-day society experience—not the least of which is produced by the popularity of cell phones, computers, and other technology. In fact, the average person swipes or scrolls through 300 feet of mobile content a day, according to Andrew Keller, global creative director of Facebook. “That's almost the length of a football field,” says one CBS News article. To avoid any negative association with the name “sensory deprivation," the experience of using a sensory deprivation tank was renamed REST (Restricted Environmental Stimulation Therapy), sometimes referred to as Flotation-REST.

What Is a Sensory Deprivation Tank?

A sensory deprivation tank is a float tank containing a foot or less of water and 800 pounds (over six pounds of salt per gallon) of Epsom salts or magnesium sulfate, which is aimed at promoting floatation. In fact, the concentration of magnesium sulfate is so high that it’s difficult for a floater to submerge underwater—keeping the person afloat in a deeply relaxed yet awake state of mind. The air that surrounds the tank is set at skin temperature, and the room is dark and soundproof. As the name denotes, the tank was designed to induce a state of sensory deprivation. When the lid is closed, the experience involves elimination of all outside sound, sight, smell, and tactile sensation from the pull of gravity. Why would a person want to deprive oneself completely of external stimulation? The tank is said to provide a deep form of meditation without the normal distractions of discomfort (such as leg cramps from sitting cross-legged). There are many pieces of emerging clinical research evidence that support the claims for the health benefits derived from a 60-minute session in a sensory deprivation tank. These include pain relief, alleviating anxiety, improving mood, reducing depression, and more.

History of the Tank

Neuroscientist John Lilly designed the first sensory deprivation tank in 1954. He wanted to study the effects of sensory deprivation on the mind. By eliminating a person’s outside stimulation, Lilly hoped to learn about human consciousness. But, in the 1960s, Lilly (along with many other scientists of the era, such as Timothy Leary) started experimenting with the effects of combining the deprivation tanks with psychedelic drugs such as LSD. This led to a controversial turn in the public’s view of Lily’s work, and the sensory deprivation tanks went out of fashion. In the 1980s the “float tanks,” as they were called, resurfaced and became popular for consumers. During that time, the industry saw a huge spike in sales. The price to actually purchase a tank in the '80s was around $10,000 (clearly out of the budget of many middle-class Americans), and an hour-long floatation session was around $70. However, the interest in sensory deprivation tanks began to wane with the advent of AIDS. Before accurate information about the spread of the disease was well known, consumers feared contracting AIDS from the use of communal water (for those who purchased hourly float tank rentals).

Health Benefits

Sensory deprivation tanks are said to have many health benefits, including inducing a clear and empty state of mind, improving focus and concentration, and promoting an overall state of relaxation. Sensory deprivation tanks are also known to promote muscle relaxation, lower anxiety, and improve depression. Other benefits include improving sleep patterns, decreasing pain, and improving a sense of well-being.

Studies on Efficacy and Safety

In a 2018 study, published in a peer-reviewed science journal called PLOS One, 50 study participants with anxiety and stress-related disorders engaged in one 60-minute REST session in a sensory deprivation tank. The study participants suffered from one of several conditions, including post-traumatic stress disorder, panic disorder, agoraphobia, or social anxiety disorder. Most of them also had depression. The study concluded that one single 60-minute session induced “a strong reduction in [the] state [of] anxiety and a substantial improvement in mood in a group of 50 anxious and depressed participants.” In addition, the study found that there were no major safety concerns or adverse events during the 60-minute course of floatation. In fact, 48 of the 50 study participants stayed in the tank for the entire 60 minutes. This indicates that even people with anxiety, who may show an aversion to new types of treatment, benefited from REST. A separate 2014 study of 65 women and men discovered that in relatively healthy participants, stress, depression, anxiety, and pain were significantly decreased, whereas optimism and sleep quality significantly increased as a result of floatation-REST.

A 2007 study conducted at Karlstad University found that those with stress-related pain from muscle tension obtained relief after 12 floatation sessions. Considerable improvement was noticed for those experiencing stress, anxiety, depression, negative mood, and poor sleep quality. After 33 sessions, study participants exhibited significant improvement in diastolic (the lower number, while the heart is resting) blood pressure.

Expert Opinion

Although studies conducted as recently as 2018 have shown positive and safe results, providing evidence supporting the claims that sensory deprivation tanks provide many health benefits, some experts are quick to point out that use of the tank is not for everyone. Dr. Phillip Muskin, a psychiatrist at NewYork-Presbyterian Hospital at Columbia University, told CBS News: “Some people might find that it [the sensory deprivation tank] freaks them out." But Muskin went on to describe some of the positive benefits as well, commenting, "When you empty your mind, be that by breath, floatation, meditation, exercise … it works by allowing our brains to do some discharge of the junk and let us go back to work."

The Tank Today

Modern-day sensory deprivation tanks are very similar to the first tank designed by Lilly. Now that the commercial use of sensory deprivation tanks is again popular, those who use them can often find float centers and spas offering paid float sessions use soft music played at the beginning and end of each float. The sessions usually last 60 minutes. Float centers and spas around the country are providing sensory deprivation tank therapy sessions that are easily accessible. The average cost of a sensory deprivation tank today is anywhere from $12,000 to $14,000, and the average hourly rental session can be between $50 to $100 or even more (depending on where the tank therapy session is rented). A person gets into the sensory deprivation tank nude and floats in the tank. If the person using the tank is more comfortable wearing a bathing suit, that is permitted as well. Some of the newer sensory deprivation tank models offer a dim blue light option for those who may be prone to being claustrophobic (fear of small spaces).

The floater has the option to leave the blue light on or turn it off to float in a heightened state of relaxation in complete darkness.

Tips for Tank Users

There are several guidelines for sensory deprivation tank users, including the following:

• Be sure to remove all jewelry.

• Shower before and after using the tank.

• Eat a light meal about a half an hour before the float session.

• Avoid caffeinated beverages several hours before using the sensory deprivation tank (since caffeine may interfere with the ability to relax).

• Avoid shaving or waxing for at least two to three hours before the session (it can result in burning from the saltwater).

• Women who are menstruating should use a tampon when using the sensory deprivation tank.

• Those who wear contact lenses may want to remove them before the session.

Not Recommended For:

• Those who are epileptic (particularly if the seizures are not well controlled by medication)

• People under the influence of drugs or alcohol

• Anyone with an infectious disease

• A person with open skin wounds

• Anyone who has thoughts of suicide

• A person with active psychosis

Women who are pregnant should consult with their health care provider before using a sensory deprivation tank. Many pregnant women have reported that floating is very therapeutic for pain caused by increased weight—eased by the lack of gravity in the tank.