A single three-hour stay and stress, information overload and sleep

In one sentence

A week after a single three-hour stay in a dark, sound-attenuated room, students reported less stress and less information overload than a group that spent the same three hours in an ordinary room; sleep and rumination did not change significantly.

The researchers' question

Does a single brief Chamber-REST session change perceived stress, sleep quality, information overload, rumination and mindfulness in young adults? The authors call their study an exploratory feasibility study. They chose students as a group particularly vulnerable to the effects of stress and sleep loss.

They describe REST as a therapeutic technique that reduces sensory input — light, sound, touch and social contact — to promote relaxation and introspection. It takes two main forms: flotation in a tank of salt solution, and Chamber-REST in a dark, quiet room.

Who took part

• 265 humanities students at a state university were recruited; 237 were analysed (mean age 22.7, 67.5% women).
• 176 completed a Chamber-REST stay and 61 were in the control group. The study group was recruited by snowball sampling; participants did not know the study's aims.
• Exclusions included past or current psychiatric or neurological disorders, psychotropic medication, alcohol within 12 hours and active suicidal ideation.
• The groups were matched on sex, age, and stress and sleep before the study, at a 2:1 ratio. The comparison covered 120 Chamber-REST participants and 60 controls.

Conditions: the stay and the control group

• Chamber-REST: a dark, acoustically attenuated room of about 5 m² with a sound level of about 15 dB; bed, armchair, small table, exercise and stretching pad, 3 m² bathroom. Participants could move and eat and drink food they brought; light- and sound-emitting devices were not allowed. Intercom to an assistant. Everyone got used to the room in full light beforehand.
• Control group: 3 hours in a bright laboratory room without sound attenuation (background about 35 dB), at a table. Reading, studying, computer work, short videos, phone. Sleeping, sitting with eyes closed, meditating and listening to music on headphones were not allowed.
• Measurement: online questionnaires two days before the stay (about the past week) and one week after it. The study ran during term, outside the exam period.

What was measured

• Perceived stress — Perceived Stress Scale PSS-10 (0–40).
• Information overload — a question about the past week, 1–10 scale. The scale was added during the study, so 91 people in the study group answered it.
• Sleep quality over the past week — 1–10 scale.
• Dispositional mindfulness — MAAS scale (15 items).
• Rumination — RRQ questionnaire (12 items).
• Satisfaction with the stay — 1–10 scale, after the stay.

Results

• Stress (PSS): a significant drop in the Chamber-REST group (p < 0.001; d = 0.38), no change in controls. Time × group interaction significant (p = 0.030).
• Information overload: a drop in the Chamber-REST group (p < 0.001; d = 0.46), a slight rise in controls. Interaction significant (p < 0.001).
• Mindfulness (MAAS): a rise in the Chamber-REST group (p = 0.002; d = 0.27), no change in controls. Interaction not significant (p = 0.068) — the authors ask for caution.
• Sleep: a small, non-significant rise in both groups; interaction not significant.
• Rumination: a similar, non-significant drop in both groups.
• Satisfaction with the stay: no difference (8.1 vs 7.9 out of 10).
• After the stay, the only significant predictor of sleep quality in the study group was stress — not mindfulness or rumination.

Subgroups: who gained most

Across the whole study group (176 people), the authors identified four levels of stress before the stay. Stress fell significantly in the high (24.6 → 18.3) and very high stress subgroups (27.1 → 21.0); mindfulness also rose in the high stress subgroup. Among those with the poorest sleep (38 people), sleep quality rose from 3.8 to 6.6 and stress fell from 21.8 to 18.1.

The authors conclude that the method was more effective for people more burdened by stress and sleeping worse, in line with meta-analyses of stress interventions.

Our note: the subgroups have no comparison group, and people with extreme scores usually land closer to the mean at the second measurement. This result points a direction; it does not prove it.

How the authors explain it

The authors propose that Chamber-REST acts as a "catalyst" for adaptive self-reflection: in silence people review everyday stressors, relationships and plans, which may lead to better coping. They draw on the Systematic Self-Reflection (SSR) model. In the team's earlier study, participants described self-reflection, processing past events, planning, catching up on sleep and a break from digital stimuli — with no difference in cortisol.

Limitations

• More women than men in the sample.
• Self-report only — no objective sleep measure such as actigraphy.
• Academic stress and performance were not measured directly.
• Logistics: sessions of several hours, a monitor present, a debrief afterwards, basic physiological needs — this limits accessibility and scale.
• Some people, e.g. with claustrophobia, may not accept a stay; the authors point to orientation beforehand and the option to leave at any time.
• Our note: assignment to groups was non-random — the control group was recruited separately — which limits causal conclusions despite matching.

The authors' figures and tables — in the original

Because of the licence, the figures are not reproduced on this site. Each is available in the full text:

• Fig. 1 ↗ — Before–after changes for five variables in both groups, with 95% confidence intervals.
• Table 1 ↗ — Descriptive statistics of the matched groups before and after — the data source of our chart.
• Table 5 ↗ — Changes in the stress and sleep quality subgroups.