What Is a Sensory Deprivation Tank Used For?

Sensory deprivation tank is relaxation therapy.
Sensory deprivation, or restricted environmental stimulation therapy (REST), is a technique by which sensory input (sound, light, smell, etc.) is minimized.

Sensory deprivation tank is relaxation therapy. It is known to help individuals suffering from chronic stress, work-related muscle pains, and gastric upsets and burn out. It may also be used for those dealing with insomnia or other sleeping disorders. Sensory deprivation, or restricted environmental stimulation therapy (REST), is a technique by which sensory input (sound, light, smell, etc.) is minimized. This practice encourages an extremely deep level of relaxation. REST is typically conducted in a float tank, in which the person is suspended in a solution of warm water and Epsom salt without sound or light.

This condition is known to evoke a relaxation reflex (RR). This reflex is the opposite of the "flight or fright” response seen in dealing with stress. RR has a direct effect on the parasympathetic system (part of the brain responsible for relaxation) and causes many positive effects on the body systems.

An hour in a float tank can serve as a power nap that leaves an individual completely refreshed and energized. An hour of floating equals as much as eight hours of normal sleep.

  • The sensory deprivation tank may also help to ease muscle tensions and mental anxieties. This may be due to the complete cessation of stimuli of sound and sight. Furthermore, the elimination of gravity on the body allows the muscles and joints to release tension and get rid of soreness. For this reason, people suffering from musculoskeletal and rheumatic conditions greatly benefit from floatation REST.
  • It provides an unparalleled level of relaxation. With the elimination of futile external stimuli, the nervous system's workload is reduced by as much as 90%. Stress-related health problems such as migraine headache, hypertension, and insomnia are similarly reduced.
  • The parasympathetic system helps to increase T-cell production to strengthen the immune system. 
  • This benefits the cardiovascular system by reducing blood pressure and heart rate.
  • It helps in reducing pain and fatigue. The increased endorphin levels also promote a general sense of well-being and happiness and therefore increase vitality and further reduce levels of stress and tension.
  • Due to the buoyancy effect of the salt water, all the muscles in the body relax into their natural state, relieving tension and muscle tightness.
  • The skin feels softer due to the emollient effect of the salts.
  • People with psychological and emotional problems such as anxiety and depression can also benefit from this therapy.
  • People report that they perceive less pain to stimuli after the floating tank experience.

This all happens whether an individual is awake in the tank. An hour’s floating offers similar physical and mental benefits to a six-hour sleep in a bed.

Can I drown if I fall asleep in a sensory deprivation tank?

No. Some people fall asleep, but the water is so buoyant that they stay afloat. The worst that can happen is getting woken up by a bit of saltwater in the eyes. Using the shower afterward is also suggested to remove the coating of Epsom salt that is left on the skin and hair.

References
Floatation tanks: https://healthywa.wa.gov.au/Articles/F_I/Floatation-tanks

https://www.researchgate.net/publication/267730317_Beneficial_effects_of_treatment_with_sensory_isolation_in_flotation-tank_as_a_preventive_health-care_intervention_-_a_randomized_controlled_pilot_trial