Insight 20223
August 31 – September 3 in Berlin
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Doctoral Student

Helena Hruby

University of Freiburg

2022: Start of three-year doctorate at the medical faculty of the Albert Ludwigs University of Freiburg on the topic: “Induction of Altered States of Consciousness Through Floatation-REST”

2020-2019: Master of Science degree in Psychology: Clinical psychology, neuro and rehabilitation sciences at the Albert Ludwig University of Freiburg

Master’s Thesis Title: Waiting in Virtual Reality

2016: Bachelor of Science degree in Psychology at the Technical University Dresden

INSIGHT 2023 Topic:

Induction of Altered States of Consciousness Through Floatation-REST


Floatation-REST (Reduced Environmental Stimulation Therapy) is a technique to induce altered states of consciousness (ASC). It has positive effects on physical and mental health and strongly reduces symptoms in patients with anxiety disorders. First designed by John C. Lilly in the 1950ies, individuals float in a dark, soundproof tank filled with salt water.

In our quantitative study we focused on ASC in healthy individuals and investigated systematically how subjects experience Floatation-REST. In a repeated-measures design employing a control condition, 50 subjects (25 female, 25 male) participated in three sessions. The control condition consisted of lying on a waterbed in a dark, soundproof room (Bed-REST). The first session was designed to experience both conditions for 30-minutes. In the two measurement sessions presented in balanced in order on consecutive days, subjects were both in the Floatation-REST or Bed-REST condition for 60 minutes each. In addition to measuring emotional well-being, anxiety, stress, relaxation, and fatigue, ASC were measured using the Phenomenology of Consciousness Inventory (PCI), the Perceived Body Boundaries Scale (PBBS), and visual analog scales assessing the sense of time.

Presented results are all significant after FDR adjustment for multiple tests. Compared to Bed-REST, state anxiety in subjects was reduced in Floatation-REST (p = .033), participants were more relaxed (p = .009) and less tired (p = .018). Floatation-REST caused a reduction in perceived body boundaries (p = .0001), a stronger loss of the sense of time (p = .007), and led to an overestimation of the float duration (p = .012). Three subscales of the PCI show stronger ASC in Floatation-REST: “altered experiences” (p = .005), “altered state” (p = .003), and “positive affect” (p = .020). Changes in body boundaries are significantly correlated with the three subscales of the PCI. The more the body boundaries dissolve during floating, the more positive the mood (r = -.454; p = .001), and the more altered states of consciousness (r = -.417; p = .003) and altered experiences (r = -.419; p = .002) are reported.

Floatation-REST primarily leads to a reduced sense of one’s body boundaries and a loss of the sense of time, state changes that occur in the context of meditation practices and the intake of psychedelics. These results demonstrate that Floatation-REST can be considered a safe method for inducing relaxation and ASC.

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