Efficacy of Footbaths With Ginger Powder on Subjectively Perceived Quality of Sleep

Efficacy of Footbaths With Ginger Powder on Subjectively Perceived Quality of Sleep: a Randomized Controlled Pilot Study

A randomized, controlled trial to explore whether warm footbaths with added ginger powder can improve the sleep quality of adults with self-perceived insomnia symptoms. Participants receive daily footbaths either with warm water alone or with added ginger powder over a period of 2 weeks.

This is a randomized controlled trial with parallel group design to explore the effects of warm water footbaths with added ginger powder (experimental) compared to footbaths with warm water alone (active comparator) on sleep quality in adults with self-perceived insomnia symptoms. Participants receive daily footbaths 1-3 hours before bedtime over a period of two weeks. The footbaths are prepared by the participants themselves and carried out at their homes. Outcome measures are assessed at baseline (pre intervention) and two weeks after baseline (post intervention). The main focus is on change in subjective quality of sleep as assessed by the Pittsburgh Sleep Quality Index (PSQI). The statistical analysis comprises analyses of variance based on linear mixed effects models.

Global score of the Pittsburgh Sleep Quality Index, score between 0=positive extreme and 21=negative extreme

Total score of the Insomnia Severity Index, score between 0=no clinically significant insomnia and 28=severe clinical insomnia

Self-reported well-being measured with a standardized sleep diary (six-point rating scale, higher values represent a better outcome)

In the evening (before going to sleep), during the two-week intervention phase between pre intervention (baseline) and post intervention (2 weeks after baseline)

Self-reported performance measured with a standardized sleep diary (six-point rating scale, lower values represent a better outcome)

In the evening (before going to sleep), during the two-week intervention phase between pre intervention (baseline) and post intervention (2 weeks after baseline)

Self-reported fatigue measured with a standardized sleep diary (four-point rating scale, lower values represent a better outcome)

In the evening (before going to sleep), during the two-week intervention phase between pre intervention (baseline) and post intervention (2 weeks after baseline)

Self-reported sleep during daytime measured with a standardized sleep diary (specification in minutes, lower values represent a better outcome)

In the evening (before going to sleep), during the two-week intervention phase between pre intervention (baseline) and post intervention (2 weeks after baseline)

Self-reported recovery ability measured with a standardized sleep diary (five-point rating scale, lower values represent a better outcome)

In the morning (after waking up), during the two-week intervention phase between pre intervention (baseline) and post intervention (2 weeks after baseline)

Self-reported well-being measured with a standardized sleep diary (six-point rating scale, higher values represent a better outcome)

In the morning (after waking up), during the two-week intervention phase between pre intervention (baseline) and post intervention (2 weeks after baseline)

Self-reported sleep latency measured with a standardized sleep diary (specification in minutes, lower values represent a better outcome)

In the morning (after waking up), during the two-week intervention phase between pre intervention (baseline) and post intervention (2 weeks after baseline)

Self-reported nocturnal awakening measured with a standardized sleep diary (specification in minutes, lower values represent a better outcome)

In the morning (after waking up), during the two-week intervention phase between pre intervention (baseline) and post intervention (2 weeks after baseline)

Self-reported sleep duration measured with a standardized sleep diary (specification in hours, higher values represent a better outcome)

In the morning (after waking up), during the two-week intervention phase between pre intervention (baseline) and post intervention (2 weeks after baseline)

Scales of the 12-Item Short Form Survey (SF-12), scores between 0=more dysfunction/impairment and 100=less dysfunction/impairment

Change in subjective feeling of overall warmth as assessed by the Herdecke Warmth Perception Questionnaire

Self-reported feeling of overall warmth and warmth at the face, trunk anterior/posterior, hands and feet measured with the Herdecke Warmth Perception Questionnaire, scores between 0=cold and 4=hot

Root mean square of successive differences (RMSSD) [ms]. HRV data are obtained from 24-hour ECG measurements with "Cardioscout Multi-ECG" (SR-Medizinelektronik, Stuttgart, Germany)

Standard deviation of normal to normal (NN) intervals (SDNN) [ms]. HRV data are obtained from 24-hour ECG measurements with "Cardioscout Multi-ECG" (SR-Medizinelektronik, Stuttgart, Germany)

The proportion of NN50 (number of pairs of successive NNs that differ by more than 50 ms) divided by total number of NNs (pNN50). HRV data are obtained from 24-hour ECG measurements with "Cardioscout Multi-ECG" (SR-Medizinelektronik, Stuttgart, Germany)

Very low frequency (VLF, 0.0033 to 0.04 Hz) from frequency domain analysis. HRV data are obtained from 24-hour ECG measurements with "Cardioscout Multi-ECG" (SR-Medizinelektronik, Stuttgart, Germany)

Low frequency (LF, 0.04 to 0.15 Hz) from frequency domain analysis. HRV data are obtained from 24-hour ECG measurements with "Cardioscout Multi-ECG" (SR-Medizinelektronik, Stuttgart, Germany)

High frequency (HF, 0.15 to 0.40 Hz) from frequency domain analysis. HRV data are obtained from 24-hour ECG measurements with "Cardioscout Multi-ECG" (SR-Medizinelektronik, Stuttgart, Germany)

Ratio of two bands from frequency domain analysis: LF band (0.04 to 0.15 Hz) and HF band (0.15 to 0.40 Hz). HRV data are obtained from 24-hour ECG measurements with "Cardioscout Multi-ECG" (SR-Medizinelektronik, Stuttgart, Germany)

24-hour measurement of the skin temperature at the feet and abdomen with "MAXIM I-Button™ DS1922L" (Maxim integrated, San Jose, USA). The gradient is calculated by subtracting the proximal value from the distal value.

Inclusion Criteria: written informed consent age between 18 and 70 years self-reported insomnia symptoms Exclusion Criteria: known organic insomnia (e.g. periodic leg movements during sleep, restless legs syndrome, sleep apnea syndrome, narcolepsy) current intake of allopathic hypnotics shift work skin lesions at the lower legs or feet known intolerance or hypersensitivity to ginger preparations acute mental disorder varicose vein (degree 3 or 4, classification according to Marshall), chronic venous insufficiency pregnancy participation in other studies insufficient knowledge of the german language

Deidentified individual participant data will be made available, in addition to study protocol and informed consent form.

The data will be made available to researchers who provide a methodologically sound proposal for use in achieving the goals of the approved proposal.