Floating therapy is a practice where you lie in a specially designed tank or pod filled with water and a high concentration of Epsom salt, creating enough buoyancy that your body floats effortlessly on the surface. The water is heated to skin temperature (92–96°F), and the environment is designed to minimize light and sound. The goal is to reduce as much external sensory input as possible, allowing your brain and body to shift into a deeply relaxed state. Most sessions last about 60 minutes, though some facilities offer longer options.
How the Tank Works
The water inside a float tank contains roughly 25–30% dissolved Epsom salt (magnesium sulfate), giving it a specific gravity of about 1.23 to 1.3. For context, that’s far saltier than the ocean and dense enough that you float like a cork without any effort. You don’t need to know how to swim, and there’s no risk of sinking. Your face stays above the surface, and your body is fully supported from head to toe.
Because the water matches your skin temperature so closely, after a few minutes you start to lose the sensation of where your body ends and the water begins. The tank is dark and quiet, which removes the constant background processing your brain normally does: filtering noise, adjusting to light, managing your posture against gravity. This combination of buoyancy, warmth, and sensory reduction is formally called Floatation-REST (Restricted Environmental Stimulation Therapy).
Effects on Anxiety and Mood
The strongest clinical evidence for floating involves anxiety reduction. A study published in PLOS One tested a single float session across a wide range of participants, including those with anxiety disorders, depression, PTSD, and other stress-related conditions. Regardless of diagnosis, floating produced very large reductions in state anxiety, with an effect size (Cohen’s d) above 2.0, which in clinical research terms is unusually powerful. For comparison, many well-established therapies produce effect sizes between 0.5 and 0.8.
The same study found significant improvements across nearly every mood variable measured: stress, muscle tension, pain, depression, and negative emotions all dropped sharply, while serenity, relaxation, and happiness increased. All of these changes reached statistical significance at p < .0001, meaning they were extremely unlikely to be due to chance. The effect on feeling "refreshed" was the single largest measured change (d = 2.39), followed closely by serenity and anxiety reduction. These benefits were consistent across all diagnostic subgroups tested, suggesting floating isn't just helpful for one type of stress.
Stress Hormones and Blood Pressure
Floating also appears to influence your body’s physiological stress response. A study examining repeated float sessions (eight total) found that participants experienced decreases in both cortisol, the body’s primary stress hormone, and mean arterial blood pressure. Interestingly, it didn’t matter whether the tank was completely dark or had some light present. Both conditions produced the same reductions, suggesting the buoyancy and sensory quiet are doing most of the work rather than darkness alone.
Pain Relief
People with chronic pain are among the most common users of float therapy. A scoping review of the research found that studies consistently reported improvements in pain intensity and frequency, fewer pain locations across the body, and greater pain tolerance after floating. However, the studies varied so widely in their designs, session protocols, and follow-up periods that researchers couldn’t pool the data into a single statistical conclusion. The evidence points in a positive direction, but the exact size and duration of pain relief still need to be confirmed with more standardized research.
Athletic Recovery
For athletes, floating shows promise as a recovery tool. Research on post-exercise floating found that blood lactate levels (a marker of muscle fatigue) were significantly lower after a float session compared to a passive rest control. Perceived muscle soreness was also significantly reduced one hour after floating. At the 12-hour mark, participants who floated still showed higher pressure-to-pain thresholds across all muscle sites tested, meaning their muscles could handle more pressure before feeling painful.
A separate study of 60 elite athletes found that a 45-minute float session after training significantly improved 15 out of 16 mood-state measures and reduced perceived muscle soreness. This combination of physical recovery and psychological reset is part of why floating has gained traction in professional sports.
What a Session Looks Like
When you arrive at a float center, you’ll typically shower, insert earplugs (provided by the facility), and step into the tank or pod. You float nude, since swimwear can create distracting pressure points. The door or lid closes but usually isn’t locked, and you can open it at any time. Music often plays for the first few minutes to help you settle in, then fades out.
The first 10–15 minutes can feel unusual. Your brain is accustomed to processing a constant stream of sensory information, so the sudden quiet may feel restless or even slightly disorienting. Most people find that this passes and gives way to deep relaxation. Some people fall asleep. At the end of the session, music or a light gently signals that your time is up, and you shower again to rinse off the salt.
Preparing for Your First Float
A few practical tips make a big difference. Avoid shaving or waxing the day of your float, because the high salt concentration will sting any tiny nicks or freshly exposed skin. The same applies to new tattoos that are still healing. Remove contact lenses before getting in. Don’t drink a lot of water right before your session, since needing to use the restroom mid-float breaks the experience. If you have long hair, tying it up helps keep it from floating across your face and creating a distraction.
Hygiene and Safety
The salt concentration itself is a significant antimicrobial factor. At 25–30% Epsom salt, the water creates an environment that’s hostile to most pathogens. Float facilities also filter and sanitize the water between every session using combinations of UV light, ozone, and hydrogen peroxide, cycling the entire volume of water multiple times. The North American Float Tank Standard provides industry guidelines for maintaining water quality, temperature, and sanitation protocols.
Floating is generally safe for most people. One documented concern involves skin infections: an outbreak traced to a portable float tank in Norway in 2017 affected both healthy and immunocompromised users, with symptoms lasting up to six weeks. This highlights the importance of choosing a reputable facility that follows established sanitation standards. If you have open wounds, active skin infections, uncontrolled epilepsy, or severe claustrophobia, floating may not be appropriate for you. Many facilities offer open-design float rooms (rather than enclosed pods) as an option for people uncomfortable with small spaces.
Origins of the Practice
The concept dates to the mid-1950s, when neuroscientist John C. Lilly built the first isolation tank at the National Institutes of Health. His original goal was to study what happens to the brain when external stimulation is stripped away. Lilly’s early tank required full submersion with a breathing apparatus, which was impractical for general use. Over the decades, the design evolved into the shallow, salt-saturated format used today, shifting the practice from a niche neuroscience experiment into a commercially available wellness service. The modern float industry has grown substantially since the 2010s, with thousands of centers now operating worldwide.