Effects of Drinking Cows’ Milk at Breakfast in Promoting Sleep-Health in Japanese University Athletes

Abstract

This study evaluates the effects of milk intake for 20 days at breakfast on diurnal type (chronotype), sleep habits and soccer performance in Japanese university male athletes attending a university soccer club. Seventy three athletes were asked to take 200 ml of cows' milk at breakfast for 21 consecutive days during November and December, 2014. Twenty athletes attending the same soccer club did not drink cows' milk for the same period of time and acted a control group. An integrated questionnaire was administered twice, before the intervention period and 1 month after it to all 93 participants. The questionnaire included questions on sleep habits and diurnal type. On the 10th day and 21st days of the intervention period, a questionnaire on performance/skill was administered to all participants. The group which drank cows' milk showed higher frequency of improvement of soccer performance than did the control group did (performance-where higher values indicate less skill: milk drinking group=29.92, control group=31.9 on day 10; milk drinking group=28.21, control group=31.9 on day 21), and also judged that their soccer performance had improved more after 21 days than 10 days of the intervention. Those participants who changed diurnal type to becoming more morning-typed were more likely to judge that their soccer performance had improved than did those who showed no change in diurnal type.

Salivary Melatonin at Night: Responding to the Night Lighting and Cow’s Milk Consumption at Breakfast in Japanese Junior High and University Students

“…Tryptophan included in the cow's milk was metabolized to serotonin in the morning and serotonin again synthesized to melatonin at night [28,29,31,48,49,59]. Therefore, the sleep latency seems to become shorter during the intervention [49] due to the melatonin synthesis which has been known as the natural sleep inducer [60] based on cow's milk intake at breakfast. This shorter sleep latency leads to the longer sleep hours for the university soccer club members.…”

“…For Japanese children, drinking cow's milk at breakfast is an important source of tryptophan and could, on the basis of a questionnaire study [47], be supposed to promote mental and sleep health. Recently, an intervention of drinking cow's milk (200 ml) at breakfast was reported to make Japanese university soccer team athletes who were originally more evening-typed than evening-typed, and this intervention also made their soccer performances in advance [49]. Another intervention study was performed for 1 month on the Japanese university soccer team members using a leaflet entitled: "Three benefits: Go to bed early!…”

Reliability and Validity of the Second Edition of Self-Evaluated Soccer Performance Score

“…The first edition of self-evaluated questionnaire for soccer performance was made by three under-graduate students who were university soccer club players. The first edition consisted of 11 questions and was used for the two studies on the intervention using a leaflet (Wada et al, 2012) which is to promote morning-typed life for sports athletes and using the recommendation of having milk at breakfast for university soccer club athletes (Kawada et al, 2016). The questionnaire on self-evaluation of soccer performance as the first edition (Kawada et al, 2016) consisted of the 11 components as follows: Question 1: Assessment of the present situation, Question 2: Visual field on playing, Question 3: Movement of foot, Question 4: Rudimentary mistake, Question 5: First touch, Question 6: Irritation on playing, Question 7: Running out of Stamina, Question 8: Injury on playing, Question 9: Body balance, Question 10: Precision of long kick, Question 11: Motivation for the practice.…”

“…The first edition consisted of 11 questions and was used for the two studies on the intervention using a leaflet (Wada et al, 2012) which is to promote morning-typed life for sports athletes and using the recommendation of having milk at breakfast for university soccer club athletes (Kawada et al, 2016). The questionnaire on self-evaluation of soccer performance as the first edition (Kawada et al, 2016) consisted of the 11 components as follows: Question 1: Assessment of the present situation, Question 2: Visual field on playing, Question 3: Movement of foot, Question 4: Rudimentary mistake, Question 5: First touch, Question 6: Irritation on playing, Question 7: Running out of Stamina, Question 8: Injury on playing, Question 9: Body balance, Question 10: Precision of long kick, Question 11: Motivation for the practice. For the second edition, additional five components were added by one professional soccer coach who had university assistant professor with A-class license for soccer supervisor which was officially given by Union for European Football Association (UEFA), a university soccer team coach and a university soccer team general manager.…”

Intervention Class Study to Promote a Morning-Typed Life for Japanese Junior High School Students Using a Picture Leaflet as a Teaching Subject

“…The serotonin can be synthesized into melatonin at night in pineal which promote fall-in-sleep at night: Protein which was consumed at breakfast could be effective for promoting the mental health through another synthesis from thyroxin and phenylalanine into dopamine in Japanese infants (Akimitsu et al, 2013). Consumption of cows' milk at morning can promote the shifting of the diurnal rhythms of infants and university athletes into morning-typed persons and promote their sleep health (Takeuchi et al, 2014;Harada et al, 2016;Kawada et al, 2016aKawada et al, , 2016b.…”