Jessica Cho, M.D. Integrative Medicine | Feb 8, 2024
Sensory deprivation tank therapy, also known as float therapy or restricted environmental stimulation therapy (REST), is a type of therapy designed to reduce anxiety and depression by removing all external stimuli in an effort to calm the body and mind. Float therapy takes place in a tank of shallow, salty water to facilitate relaxation and stress relief.
Floatation therapy is a popular wellbeing practice, with hundreds of commercial float therapy tanks operating in the U.S. and Europe. However, scientific research on the purported mental and physical health benefits of sensory deprivation tanks is limited.
Read on to learn more about who may be a good fit for sensory deprivation tank therapy, potential health benefits and risks and where to find float therapy options.
What Is a Sensory Deprivation Tank?
Sensory deprivation tank therapy was started by physician and neuroscientist John Lilly, M.D., in the 1950s. Lilly developed float therapy as a way to see how the central nervous system would respond to being in an environment devoid of external sensory input. Typically, the water is about 12 inches deep, contains 25% to 30% Epsom salts and is set to around 95 degrees Fahrenheit. Tanks look like a tub with a convertible top that can be easily opened and closed.
The purpose of a sensory deprivation tank is to isolate and cut yourself off from all outside stimulation, says Graham Simpson, M.D., a preventive medicine doctor with Opt Health, an online telehealth practice that caters to men’s health and wellness. “There is no light or sound, and the temperature of the water is the same temperature as one’s body temperature,” explains Dr. Simpson.
During sensory deprivation tank therapy, an individual is able to float without any effort to remain buoyant, says Leland Stillman, M.D, a functional and integrative medicine doctor based in St. Petersburg, Florida. Many people describe the sensation of floating in a sensory deprivation tank as “feeling like they’re floating on air,” says Dr. Stillman. “You can relax completely because you don’t need to use any of your postural muscles to maintain your body’s structure or posture. The only muscles working are the respiratory muscles, and to a certain extent, your neck and abdominal muscles, he explains.
Many wellness centers or spas offer sensory deprivation tanks. Flotation therapy costs range from $75 for a 30-minute session to $100 and up for an hour or longer, says Dr. Stillman. In the tank, you can wear either a swimsuit or float naked, depending on the rules of the wellness center or spa, notes Dr. Stillman.
Health Benefits Of A Sensory Deprivation Tank
Health benefits of floatation therapy are similar to those gained from meditation, say Dr. Stillman and Dr. Simpson. “Many people have hectic lifestyles full of distractions. “[Sensory deprivation tank therapy] is a way to mentally reset,” explains Dr. Simpson. “This type of reset can benefit both mental health and physical health in several ways.”
Below are the most common health benefits a person may experience with float therapy.
Relaxation
The most common benefit reported from people who do float therapy is that it helps them relax, says Dr. Stillman. While there haven’t been many scientific studies done on float therapy, one small study published in Human Brain Mapping shows a connection between just one 90-minute float therapy session and feeling more relaxed[1].
For the study, 56 healthy participants experienced a 90-minute float therapy session, undergoing magnetic resonance imaging (MRI) before and after the session. Then MRI data was analyzed using multivariate distance matrix regression (MDMR), a type of whole‐brain “searchlight” approach.The study found that the MRIs done after the float therapy sessions showed reduced stimulation of the nervous system, suggesting people felt more relaxed after trying the sensory deprivation tank.
May be Helpful in Reducing Anxiety
Sensory deprivation tank therapy may also help reduce anxiety. A very small study in BMC Complementary Medicine and Therapies found that individuals who experienced 12 sessions of float therapy had greater decreases in anxiety and depression than participants in the study control group who didn’t do floatation therapy[2]. However, keep in mind that float therapy can serve as a supplemental treatment to other treatments, such as therapy and medication rather than the primary treatment for anxiety and depression.
Possible Improved Sleep Quality
The BMC study also found that participants who did float therapy for 12 weeks had fewer sleeping difficulties than those who didn’t use the sensory deprivation tank. The reason sensory deprivation tank therapy can help improve sleep is because it helps the body become more relaxed, priming it for rest,” says Dr. Simpson.
In another very small study, six healthy individuals experiencing insomnia did 12 45-minute float therapy sessions. The results were mixed, showing that float therapy helped three of the people sleep better—even two months after the sessions ended—while the others experienced no improvement in sleep quality[3].
May Help Lower Blood Pressure
A review of scientific studies and articles in the Canadian Journal of Health Technologies indicates that during a 90-minute floatation session, float therapy may significantly (temporarily) reduce blood pressure, a major risk factor for heart disease and stroke[4].
In the same way that stress can raise blood pressure levels, feeling relaxed can lower blood pressure, explains Dr. Simpson. This is because relaxation lowers levels of cortisol, the “stress hormone” associated with high blood pressure. To lower blood pressure long-term, it’s important to regularly find ways to relax, and float therapy may be a way to do this, says Dr. Simpson.
Might Aid Muscle Recovery
If you are an athlete or work out regularly, incorporating sensory deprivation tank therapy into your post-workout may be beneficial for your body’s recovery. Some research indicates that float therapy could help relieve muscle soreness.
“The warm water helps with muscle and joint pain,” explains Dr. Simpson. Also, since float therapy is linked to better sleep, some athletes may choose to do it the day before a big athletic event so they wake up well rested. Flotation therapy can also help soothe joint and muscle pain after exercise.
Sensory Deprivation Tank Side Effects
Both Dr. Stillman and Dr. Simpson say that sensory deprivation tank therapy is generally safe and low-risk. However, there is still a low risk for potential side effects, including:
- Racing thoughts
- Dry mouth
- Visual or auditory hallucinations
- Intense fear or anxiety
- Difficulty breathing
- Mania
- Nausea
- Earache
- Desire to hurt oneself or others (rare)
Dr. Stillman says that some people report feeling too relaxed after their float sessions. Because of this potential for drowsiness, make sure you’re alert enough to drive home after a session or arrange for someone to drive you home.
Health Risks of a Sensory Deprivation Tank
This type of therapy may not be a good fit for everyone. People who are epileptic or have low blood pressure or kidney disease should talk to their doctor about sensory deprivation therapy to avoid potential adverse effects.
Who Might Benefit From A Sensory Deprivation Tank?
People who are a good fit for floatation therapy are those who’ve been under a lot of stress, such as busy parents or busy employees. “The more stress you’re under, the [better] fit you are for the float tank,” says Dr. Stillman.
Since the health risks and side effects of sensory deprivation tank therapy are minimal, Dr. Simpson says it can be beneficial for most people who want to try it, especially individuals interested in new ways to practice mindfulness. If you’re looking for a way to relax and recharge from constant stimulation and don’t have the medical conditions or health risks mentioned above, you may benefit from float therapy.
