Do Highly Sensitive People Benefit More from Float Therapy?

Although the first float tank was developed decades ago in the 1950s, float therapy did not become popular in the US until more recently. In float therapy, also known as flotation-REST (Restricted Environmental Stimulation Therapy), a person enters a pod filled with just enough salt water (created by dissolving Epsom salts or magnesium sulfate) for them to float. To reduce sensory input, the water is maintained at a lukewarm 93.5 degrees Fahrenheit, similar to our skin temperature. After climbing into the pod, one closes the lid so it is completely dark inside, wears earplugs to block out any remaining sound, and floats on their back for about an hour. This flotation experience, during which one is deprived of sensory stimulation, is thought to lead to an array of health benefits.

Although sample sizes tend to be small, recent studies have found benefits including decreased stress, lower levels of anxiety and depression, improved mood, and better sleep. Some participants also report altered states of consciousness, including mild changes like “weightlessness, altered perception of time, mental imagery, changes in body perception, and emotional expression” and stronger changes like, “complex inner scenery, experiences of hearing music, and out-of-body experiences” (p. 1496). In general, people who have stronger altered states of consciousness report greater benefits of float therapy.

Like with other forms of therapy, people do not benefit equally from flotation therapy. Researchers suggest that certain individual differences, particularly a person’s sensitivity, may affect one’s experience in a float tank. The highly sensitive person is more sensitive in multiple ways, including physical sensitivity (to pain), psychological sensitivity (to different emotions), environmental sensitivity (to sound and light), and social sensitivity (to social interactions). Highly sensitive people are especially attuned to the emotions of others as well as their own. They tend to be conscientious and careful, thoughtful and imaginative, with a rich inner life. However, these traits come at a cost. In Western society, highly sensitive people may be perceived negatively as they are more introverted and shy, and are more prone to mental health issues like depression, anxiety, and burnout. In the modern world with its multiple demands and constant stimulation, the highly sensitive person may be particularly overwhelmed, and may therefore benefit more from the sensory reduction provided by float therapy.

Thus, Jonsson et al. (2014) sought to compare the benefits of flotation therapy for people with high versus low sensitivity. The researchers recruited 57 psychology students (19 men, 37 women) in Sweden ranging from age 19-63 (Mean age = 31.93 years) who had no previous experience in a float tank. Participants first completed self-report surveys at home, which included the Highly Sensitive Person Scale (example questions: “Are you easily affected by other people’s moods?" “Do you find loud noises uncomfortable?”), the Hospital Anxiety Depression Scale, the Mystical Experience Scale, and the Tellegen Absorption scale that measures immersion in everyday experiences (example statement: “While watching a movie, a TV show, or a play, I may become so involved that I may forget about myself and my surroundings and experience the story as if it were real and as if I were taking part in it.”). Then, they participated in a 45-minute flotation-REST session. Afterward, they completed another scale that measured the Altered States of Consciousness through statements including, “My thoughts slowed down.” “With closed eyelids, I saw colors.” And “I got original ideas.”

Results indicated that as expected, highly sensitive people had greater altered states of consciousness than less sensitive people. In addition, findings confirmed that prior to the flotation session, highly sensitive people were higher in anxiety, absorption, and mystical experiences. The researchers conclude that flotation therapy may be a promising treatment for highly sensitive people and may help to induce mindfulness, thus reducing stress and anxiety.

Float therapy may give highly sensitive people a valuable respite from overstimulation

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However, as with much of the current research on flotation therapy, this study has numerous limitations. The sample was small and not generalizable, consisting of only psychology students in Sweden. Notably, the researchers did not directly measure stress, anxiety, or other indices of psychological well-being after the float session. Additionally, participants only engaged in one session, whereas effects may differ over multiple sessions or with greater time. Finally, given the lack of controlled experimental manipulation, we do not know the driving force behind highly sensitive people’s Altered States of Consciousness. Was it the sensory reduction that was important as suggested by the authors, or could the floating alone or the Epsom salts have led to these experiences? Or, could it have simply been the placebo effect combined with the powerful imagination of highly sensitive people?