Effect of low-caffeine green tea against sleep and stress in the elderly
- Conditions
- Sleep, Stress
- Registration Number
- JPRN-UMIN000016533
- Lead Sponsor
- Keiko Unno
- Brief Summary
Epidemiological and animal studies have demonstrated that ingestion of green tea enhances healthy life. However, caffeine in green tea can interfere with sleep. In this report, we examined the effect of green tea with lowered caffeine, low-caffeine green tea, on stress and sleep of the elderly. The participants (n=10, mean age 89.3 y) drank five cups/day of standard green tea for 1 week. Subsequently, they drank five cups/day of low-caffeine green tea for 2 weeks. Salivary alfa-amylase activity (sAA) was measured as a stress marker. Sleep stages were measured using a portable electroencephalography (n=7, 6 female and 1 male). The level of sAA in the morning (sAAm) was significantly lower when the participants drank low-caffeine green tea than standard green tea. While the levels of sAAm were different among individuals, lower sAAm correlated with a higher quality of sleep. In those participants whose sAAm was lowered by the ingestion of low-caffeine green tea, some sleep parameters improved. Daily ingestion of low-caffeine green tea may be a beneficial tool for improving the quality of sleep of the elderly via the suppression of stress, although further research is required to fortify this hypothesis.
- Detailed Description
Not available
Recruitment & Eligibility
- Status
- Complete: follow-up complete
- Sex
- All
- Target Recruitment
- 10
Not provided
Taking sleep-inducing drug and tranquilizer Smoker Diagnosed as inadequate to participate in the study by a doctor
Study & Design
- Study Type
- Interventional
- Study Design
- Not specified
- Primary Outcome Measures
Name Time Method Alterations in brain waves and salivary amylase activity in the elderly that drank low-caffeine green tea.
- Secondary Outcome Measures
Name Time Method Physical condition, Sleeping time, Replying to a questionnaire (subjective stress)