An Exploratory Study to Detect the Effects of the Combined Intake of Gamma-aminobutyric Acid (GABA) and L-theanine on Sleep by Wearable Device

ObjectivesSleep disorders are a global issue, and supplements for sleep and new devices for daily sleep status assessment are becoming widely available. Gamma-aminobutyric acid (GABA) and L-theanine are commonly used dietary supplements to improve sleep. This study examined whether the combined GABA (700 mg/day) and L-theanine (200 mg/day) intake improve sleep in adults with sleep problems and whether the Fitbit Charge 5 can detect sleep status changes the supplements induced. MethodsParticipants received the supplements for four weeks, and changes in sleep quality measured using the Pittsburgh Sleep Quality Index (PSQI) and sleep-related data measured by the Fitbit Charge 5 were evaluated before and after the intake of the supplements. ResultsResults obtained from 19 participants indicated significant improvement in the total PSQI score (9.42 {+/-} 1.80 to 6.26 {+/-} 1.66 (mean {+/-} standard deviation), p<0.001). Sleep score improvement was insignificant for the Fitbit data(N=17). However, sleep recovery scores improved significantly (p=0.042). In addition, heart rate during sleep decreased with a significant difference of 1.3 bpm decrease in the first week of intake (p = 0.045). ConclusionsThe simultaneous intake of GABA and L-theanine improved sleep in adults, and the Fitbit Charge 5 could detect improvements in objective information regarding sleep status.