If you struggle with chronic stress, racing thoughts at night, difficulty sleeping, anxiety, or low mood, float therapy may offer a natural, restorative way to help reset your nervous system. Learn about the science behind float therapy.
Float therapy, also called flotation therapy or Flotation-REST (Restricted Environmental Stimulation Therapy), involves lying effortlessly in a shallow pool of warm water saturated with over 1,000 lbs of Epsom salt (magnesium sulfate) inside a quiet, dim (often near-dark) float room. The water’s high buoyancy supports your body in a zero-gravity environment that many people describe as “weightless,” while the reduced light, sound, and touch input creates a uniquely low-stimulation environment.
Importantly, float therapy isn’t a brand-new wellness trend. Researchers have studied flotation-REST for decades, exploring how reduced sensory input and deep physical relaxation may affect stress physiology, mood and sleep.
Below, explore peer-reviewed studies investigating the science behind float therapy.
Peer-reviewed studies on the impact of float therapy on stress, depression, anxiety and sleep quality
Float therapy reduces cortisol levels and blood pressure
Today, there is a lot of talk about cortisol and how it affects the body. Cortisol is a hormone produced by the adrenal glands that plays a vital role in the body’s stress response, metabolism, immune function, and blood sugar regulation. Often called the “stress hormone,” cortisol is essential for survival in short bursts, helping the body respond to challenges and threats.
However, chronically elevated cortisol levels, which can occur with ongoing stress, poor sleep, or burnout, can negatively affect the mind and body. Persistently high cortisol has been associated with symptoms such as fatigue, anxiety, difficulty sleeping, weight gain (especially around the abdomen), increased inflammation, brain fog, and weakened immune function—highlighting why stress regulation has become such an important focus in modern wellness discussions.
What clinical research shows
One of the early most prominent studies published in 1989 examined changes in cortisol and blood pressure after repeated flotation-REST sessions. Turner et al. found in a controlled study that repeated float therapy session (8 total) resulted in a significant decrease in plasma cortisol levels and mean arterial pressure. As a result, study participants experienced:
- Improved nervous system balance: Lower cortisol reflects a shift away from sympathetic (“fight-or-flight”) dominance toward parasympathetic (“rest-and-digest”) activity, resulting in slower resting heart rate, reduced muscle tension and improved heart-rate variability.
- Reduced inflammation and immune dysregulation: Lower cortisol levels leads to more balanced immune response, reduced low-grade chronic inflammation and improved wound healing and tissue repair.
- Better glucose regulation and metabolic health: Cortisol raises blood glucose by stimulating gluconeogenesis. Therefore, lower cortisol contributes to improved insulin sensitivity, reduced blood sugar spikes and less central (abdominal) fat accumulation over time.
- Improved sleep architecture: Higher cortisol levels and blood pressure are strongly linked to sleep-onset insomnia and fragmented sleep. Therefore, modalities that reduce these signatures result in being able to fall asleep faster, fewer nighttime awakenings, and improved slow-wave (deep) sleep.
- Reduced cardiovascular strain: Lower blood pressure levels decrease workload on the heart and arterial walls and improve tissue oxygenation. This results in improved endothelial (blood vessel lining) function, lower long-term risk of hypertension-related damage, and enhanced oxygen and nutrient deliver to support muscle and organ health.
Float therapy can reduce anxiety and depressive symptoms (short-term relief in clinical samples)
In many people, anxiety is maintained by persistent threat monitoring, body tension, and sensory hypervigilance. The zero-gravity, low-stimulation environment of float therapy has been clinically shown to interrupt that loop by reducing incoming stimuli and allowing the central nervous system (CNS to slow, settle and experience a deep calm or “serenity.”
What clinical research shows
In a peer-reviewed study published in PLOS ONE in 2018, Feinstein et al. conducted an open-label clinical trial examining whether a single session of float therapy could reduce symptoms of anxiety, stress, and depression by minimizing sensory input to the nervous system.
- 50 participants with anxiety- and stress-related disorders—most of whom also had unipolar depression—completed self-report measures immediately before and after a one-hour float session.
- The study found large and immediate reductions in state anxiety (with an exceptionally strong effect size), along with significant decreases in stress, muscle tension, pain, depression, and negative affect.
- Participants also reported marked improvements in mood, including greater serenity, relaxation, happiness, and overall well-being. These effects were strongest in those with the highest initial anxiety levels, bringing post-float anxiety closer to that seen in non-anxious individuals.
Findings from a recent 2024 study
In 2024, Garland et al. published a randomized peer-reviewed study assessing the safety and feasibility of float therapy as holistic treatment for anxious and depressed individuals.
- 75 individuals with anxiety and depression were randomized to complete six sessions of float therapy in different formats.
- Six sessions of float therapy were reported as feasible, well-tolerated, and safe in anxious and depressed individuals.
- Participants reported positively-valenced experiences.
Float therapy supports better sleep quality
Sleep onset problems often track with cognitive and physiological arousal (racing thoughts, tension, elevated alertness). Floating has been shown to lower arousal and improve relaxation conditioning, making it easier to transition into sleep later that night.
What the clinical research shows
A study published in 2022 in Sleep Science by Norell-Clarke et al. investigated the effects from flotation-REST on six adulted diagnosed with clinical insomnia. Participants completed 12 flotation sessions (45 minutes each) over about seven weeks, without other concurrent sleep treatments. Daily sleep diaries tracked key sleep measures: sleep onset latency (time to fall asleep), wake after sleep onset (nighttime awakenings), total sleep time, and sleep efficiency.
- Not all participants improved, but several did show meaningful changes.
- Three of the six participants showed improvement in their primary insomnia symptom (either shorter time to fall asleep or reduced waking after sleep onset). Two participants also had better sleep efficiency that persisted at a 2-month follow-up.
- Insomnia severity decreased for three participants, and depressive symptom severity decreased for five participants.
Try evidence-backed float therapy at Sanctuary Float Spa
Float therapy isn’t just a relaxing experience—it’s backed by decades of scientific evidence suggesting real benefits for stress reduction, improved sleep quality, and mental well-being.
By creating a unique sensory-free environment, float therapy allows the nervous system a rare opportunity to rest, allowing stress pathways to shift toward greater parasympathetic (rest-and-digest) activity, which supports better sleep and improved emotional regulation.
If you struggle with chronic stress, racing thoughts at night, difficulty sleeping, anxiety, or low mood, float therapy may offer a natural, restorative way to help reset your nervous system. Many clients at Sanctuary Float Spa report that their first float session leaves them feeling significantly calmer, more centered, and better equipped to handle everyday stressors—effects that can carry over into improved sleep and mental clarity.
Ready to see how float therapy can support your stress, sleep, and mental health? Book a session at Sanctuary Float Spa and give your body and mind the reset they deserve.