Athletes often have poor sleep quality before a competition. Sleep quality can stabilize mood and improve sports performance. The randomized controlled study explored the effects of cranial electrotherapy stimulation (CES) on the physiology, psychology, response-ability, and sleep quality of athletes who had poor sleep quality before a competition. Athletes who had poor sleep quality (Pittsburgh Sleep Quality Scale score > 5) and had a competition in less than 2 months were recruited. The athletes were grouped into the CES group, which received a 2-week CES treatment (n = 20, age = 21.55 ± 2.26 years), and a placebo group (n = 20, age = 21.05 ± 1.46 years), which received a 2-week sham CES treatment. We performed biochemical analysis, a simple reaction time test, choice reaction time tests, the Profile of Mood States, heart rate variability (HRV), and an Actigraphy activity recorder to measure outcomes before and after the interventions. Our results revealed no significant differences in blood urea nitrogen, creatine phosphate, testosterone, cortisol, and saliva pH between and within groups (p > 0.05). Significant decreases in negative mood states (i.e., anger, tension, and depression) and choice reaction time in the CES group were noted (p < 0.05), moreover, the anger, tension, and depression mood decreased from 0.36 ± 0.45 (95% CI = 0.16-0.55), 1.62 ± 0.97 (95% CI = 1.19-2.04), and 1.67 ± 1.06 (95% CI = 1.20-2.13) to 0.11 ± 0.20 (95% CI = 0.02-0.19, p = 0.03), 1.12 ± 0.74 (95% CI = 0.79-1.44, p = 0.04), and 0.81 ± 0.75 (95% CI = 0.48-1.13, p = 0.001), respectively. Additionally, choice reaction time was decreased from 420.85 ± 41.22 ms (95% CI = 402.78-438.91) to 399.90 ± 36.71 ms (95% CI = 383.81-415.98, p = 0.04) and was also noted in the CES group. For HRV, and Actigraphy activity for sleep measure, the low-frequency (LF)/high-frequency (HF) ratios changed from 1.80 ± 1.39 (95% CI = 1.19-2.40) to 1.21 ± 0.73 (95% CI = 0.89-1.53, p = 0.10), and sleep efficiency decreased from 87.94 ± 6.76% (95% CI = 84.97-90.90) to 81.75 ± 9.62% (95% CI = 77.53-85.96, p = 0.02) in the CES group. The change in LF/HF after the trial were found between CES and placebo groups (p < 0.05). Yet, the decrease in sleep efficiency in the placebo group were noted (p < 0.05). However, we found that the regression line for sleep efficiency was decreased less during the study while using CES. The CES intervention could reduce negative emotions, improve choice reaction times, enhance the parasympathetic and sympathetic nerve activity imbalances, and slow sleep efficiency deterioration. Regardless, small effect sizes of the application of CES on psychology response, response-ability, and sleep efficiency were concluded in athletes with poor sleep quality before a competition.
Keywords: cranial electrotherapy stimulation; heart rate variability; sleep efficiency.