Restricted environmental stimulation therapy

Restricted environmental stimulation therapy or flotation therapy is therapy that is undertaken by floating in a warm salt water in a float tank.

Flotation therapy developed from the research work of John Lilly although he was not primarily interested in therapy, rather in the effect of sensory deprivation on the human brain and mind.

People using early float tanks discovered that they enjoyed the experience and that the relaxed state was also a healing state for many conditions including stress, anxiety, pain, swelling, insomnia and jet lag.

As a result float tanks were produced for commercial uses and commercial float centers offering flotation therapy opened in several countries during the period from 1980 to the present day when there are hundreds of flotation centers in dozens of countries. In almost all cases these float centers offer wellness treatments and in particular the release of stress. The San Francisco Bay Area has seen recent growth in such centers.

Research into flotation therapy (as opposed to just the effect of isolation) began in the USA at Ohio State University where floating was shown to improve creativity in Jazz musicians, accuracy in rifle shooting, focus before academic examinations and stress relief, among others.

Research in Sweden has demonstrated the therapeutic effect on stress and pain.

The technique takes advantage of an innate, natural inclination to relax when floating at a comfortable temperature. The temperature is that which allows natural heat generation to escape without the need for muscle action to raise body temperature in homeostasis. The floating posture, usually the supine position (although the prone position with chin supported on elbows is recommended for pregnant women), allows all the postural muscles to relax. The water pressure on the immersed skin is lower than the blood pressure and thus blood flow continues in skin capillaries. This is in contrast to normal bed rest where local contact pressure inhibits blood flow requiring regular adjustment of posture. When people cannot adjust their posture in bed, e.g. in some illnesses, bed sores can result. When floating there is no tendency to adjust posture and a person can float immobile for many hours.

The natural tendency of the body in the floating posture at the correct temperature is to dilate the blood vessels, reducing the blood pressure and maximizing blood flow. The brain activity normally associated with postural muscles is reduced to a minimum. In this state, which we can call the floating state, natural endorphins are released reducing pain. Lactic acid removal is accelerated. Flow in the lymphatic system is increased.

The effect on stress
Perceived stress can be correlated with increased levels of cortisol and in flotation therapy there is a natural tendency for cortisol to be reduced. For this reason, flotation therapy is one of the few noninvasive techniques available to manage stress when it is a factor in reducing a person's ability to cope with normal life. Flotation therapy is a fast technique in this respect. The Swedish research was based on 40 minute float sessions. This compares well with other management techniques such as long vacations.

There are some similarities with the age old long hot bath. However, the main differences are that in floatation all sensory impressions are absent, temperature is maintained at the correct level and the bath is large enough to float without touching the sides of the float unit. These factors allow the individual to achieve much deeper level of relaxation, and therapeutic benefit, than would otherwise be possible.

The effect of the salt
Most float tanks use Epsom salt, magnesium sulfate, in high concentration so that the relative density of the solution is about 1.25. (Lilly recommended 1.3 but this requires operating very close to saturation with the risk of recrystallization). The density assists floating particularly making the head buoyant so that the nose and mouth are well out of the water for breathing.

It has recently been discovered that there is a secondary effect which is important to flotation therapy. Magnesium is absorbed through the skin due to natural molecular diffusion. This tends to correct magnesium deficiency. Magnesium is absorbed from the diet but in many areas of the world, over-cropping without adequate replacement of magnesium makes the normal diet low in magnesium.

The body naturally optimizes the levels of magnesium, so there is no overload effect from floating in the salts for extended periods.

It is noted that there is no "flotation therapist", although there is a need to instruct the floater and need to maintain the equipment in a safe condition. However, flotation therapy is compatible with other therapies as a preparation or conjunct activity. Examples include massage, talk therapy, and hypnosis.