The Long-term Impact of Massage Chairs on Sleep Quality.

Study Design The current study will assess the impact of daily usage (30 consecutive automatic massage sessions) of deep relaxation full body massage sessions using the 4D new generations' massage chairs in individuals suffering from insomnia. The massage chair will be located in patients' house/bedroom during the whole trial period.

Participants will follow a crossover design with one-month interval period for three months in total. Participants will be randomly assigned into two equal-sized groups receiving the intervention (massage) following a distinct pattern: for the Group-1: one month on, one month off, one month on, and for Group_2: one month off, one month on, one month off. During the "on" period, massage chair is located at participant's house while during the "off" period, massage chair is removed from participant's house.

During the "on" periods, participants could use the massage chair prior to bed time (last action before sleeping) and select from one of twelve programmed relaxation massage options. They were required to use the chair for at least 30 minutes daily, primarily before going to bed. The study was approved by the Human Research and Ethics Committee of the University of Thessaly (2334-5/4-2/7.2.2024). All Subjects gave their written informed consent prior to study participation.

Procedure All measurements will be conducted at the participants' own homes. Massage sessions will be performed in the participants' home prior to bedtime, utilizing the automatic massage chair provided during the study period.

The initial screening requires that all participants score ≥16 on the Athens Insomnia Scale (AIS-8). The Pittsburgh Sleep Quality Index (PSQI) was provided for participants to complete every 30 days over the three-month period. Additionally, during the first visit, all participants completed a series of validated questionnaires assessing quality of life, depression score, sleep quality, stress, and general fatigue. The same questionnaires were also completed during the final visit. After each visit and immediately after the completion of the 30 min automatic massage, participants will be connected to the portable polysomnography system and they will stay alone to follow their bedtime routine. The study recording will be completed when the participant wakes up and disconnects the system.

Questionnaires The following questionnaires will be administered using the interview method by experienced researchers.

• The Athens Insomnia Scale 1 and the Pittsburgh Sleep Quality Index (PSQI) will be used to assess sleep quality and the existence of any sleep abnormalities.
• The Short Form survey 36-item 36 quality of life questionnaire (SF-36) will be used to assess the health-related quality of life.
• The Beck Depression Inventory (BDI) questionnaire will be used for the assess symptoms of depression.
• The Perceived Stress Scale (PSS) will be used to assess the stress levels.

Body Composition Body composition will be assessed using anthropometric measurements, including BMI and bioelectrical impedance analysis with a Tanita DC-360S device (Tanita Corporation, Tokyo, Japan), following standard methodology.

Sleep Assessment A portable sleep monitoring system will be used to assess sleep quality and quantity (Home Sleep Test, Somnomedics, GmbH, Germany). The system records EEG, EOG, and EMG signals overnight. EEG data will be analyzed in 30-second epochs using SomnoMedics PSG analysis software (Domino panel ver. 3.0.0.8) with manual editing. The HomeSleepTest REM+ device will be used for PSG, with electrodes placed according to the 10/20 system on key brain regions: Fp1 (left) and M1 for EEG, and near the eyes for EOG. This setup ensures accurate monitoring of sleep architecture and high-fidelity recordings of brain activity and eye movements.

Analysis of the sleep study will be reported as follows: Total Sleep Time (total amount of sleep time scored during the total recording time); Sleep Efficiency (Total sleep time/Time in bed); Sustained Sleep Efficiency (Total sleep time/(Time in bed - Sleep laten-cy stage 2); Sleep Latency (the period of time it takes for a person to fall asleep after they have gone to bed and tried to initiate sleep); Sleep Latency N1 (the period of time between wakefulness and when sleep begins); Sleep Latency N2 (the period of time between time in bed and sleep onset stage 2); REM Latency (the amount of time elapsed between the onset of sleep to the first REM stage).

Massage Session Automatic Electric Massage Chair (AEMC) The Z1 Full Body 4D Massage Chair (Z1-SL Massage Chair, China, www.back2life.gr) will be used in the current study. The Z1-SL chair features a curved rail mechanism for both S-shaped (horizontal) and L-shaped (vertical) massages, covering areas from the head down toes. It includes 58 air cushions for air compression massage, while intelligent mechanical arms, rotating 360°, follow the body's contour, scanning and targeting specific areas for treatment.

The chair integrates a 4D massage system with professional techniques such as kneading, tapping, shiatsu, stretching, air compression, roller, and thermal massage. These techniques allow multidimensional effects in width, length, and depth, tailored to individual needs. Twelve automated programs vary in intensity, and the roller mechanism adjusts to body widths of 3 to 22 cm for focused application to areas like the cervical spine, back, and lower back.

The chair's infrared preheating function (carbon fiber-based) enhances relaxation and circulation by heating the back, pelvis, and thighs. This feature, combined with an extendable foot section and an airbag/roller system, ensures comfort for individuals of different sizes, providing muscle relaxation, fatigue relief, and improved blood circulation.