The aim of the study was to investigate whether or not 33 flotation sessions were more effective for stress-related ailments than 12 sessions. Participants were 37 patients, 29 women and 8 men, all diagnosed as having stress-related pain of a muscle tension type. The patients were randomized to one of two conditions: 12 flotation-REST treatments or 33 flotation-REST treatments. Analyses for subjective pain typically indicated that 12 sessions were enough to get considerable improvements and no further improvements were noticed after 33 sessions. A similar pattern was observed concerning the stress-related psychological variables: experienced stress, anxiety, depression, negative affectivity, dispositional optimism, and sleep quality. For blood pressure no effects were observed after 12 sessions, but there was a significant lower level for diastolic blood pressure after 33 sessions. The present study highlighted the importance of finding suitable complementary treatments in order to make further progress after the initial 12 sessions.
Keywords: Flotation-REST, pain, relaxation response, stress, anxiety, depression, negative affectivity, dispositional optimism, sleep quality.
Relaxation has become increasingly popular as a pain-relieving intervention (Bood, Sundequist, Kjellgren, Nordstrom, & Norlander, 2005). It has been suggested that relaxation works by breaking a vicious circle of pain (Linton, 1982). This is in accordance with the neuromatrix theory of pain (Melzack, 2001) which suggests brain mechanisms for chronic pain and also indicates new forms of treatment. Relaxation exercises offer the means to reduce physiological and psychological reactions to stress (Sandlund & Norlander, 2000). Different relaxation techniques often lead to specific psychological and physiological changes labeled the 'relaxation response' (Benson, 1975).
In the present study, a floating tank was used to induce the relaxation response (RR). In flotation-REST (Restricted Environmental Stimulation Technique) an individual is placed in a horizontal floating posture and immersed in highly concentrated salt water in an environment (the floating tank) where all incoming stimuli are reduced to the barest minimum during a short period. The flotationREST technique is not strongly influenced by expectancy-placebo (Norlander, Kjellgren, & Archer, 2001) or by attention-placebo (Bood et al., 2005). Several studies have shown the incidence of positive effects (for a comprehensive review see Bood et al., 2006), such as increased well-being, mild euphoria, increased originality, improved sleep, reduced stress, reduced tension and anxiety, reduced blood pressure and reduced muscle tension. A recent meta-analysis (van Dierendonck & te Nijenhuis, 2005) investigated flotation as a stress-management tool. The study included 25 articles with a total number of 449 participants. The results showed that the flotation technique has positive effects on physiology (e.g., lower blood pressure), well-being, and performance. However, there were some limitations in the original studies (e.g., generally small sample si/es, lack of standardization of the frequency and duration of the sessions) and therefore the available data did not give any information on how many sessions of REST would be desirable for different groups of patients.
Several studies have been performed that apply flotation-REST as a method to alleviate different types of pain conditions (Kjellgren, Sundequist, Norlander, & Archer, 2001). In a series of studies performed by the Human Performance group, Karlstad University, Sweden, it has been shown (e.g., Bood et al., 2006) that a schedule with two periods of two treatments per week for three weeks, separated by a week without treatment, thus giving 12 flotation-REST treatments twice a week during 6 weeks (over a total of 7 weeks), was effective for most of the participants. The positive effects of the flotation-REST therapy typically were maintained four months after treatment. …