the number of older adults affected by dementia has been rising significantly in japan and 
 a number of other countries1 , 2 . mild cognitive impairment ( mci)3,4,5,6 is considered to be a 
 preclinical stage of dementia . studies have revealed that approximately 10% to 15% of people 
 with mci progressed to dementia annually7,8,9 . in 
 order to reduce the number of people who experience cognitive dysfunction , it is important 
 to delay , or even reverse , the progression of mci to dementia . while aging is regarded as the greatest risk factor for 
 cognitive dysfunction10 , several studies 
 have indicated that habitual exercise and physical activity may have a beneficial effect on 
 the prevention of dementia11,12,13,14,15 . a wide variety of exercises , such as walking , have been recommended for older adults in 
 efforts to maintain and promote health . aquatic exercises in particular are recommended for 
 older adults with obesity and osteoarthritis16,17,18 . one such aquatic exercise regimen is synchronized swimming , which is suitable for older 
 adults , as the swimmer may stand on the floor of a shallow pool19 . while a number of studies have indicated that land - based exercise exerts a beneficial 
 effect on cognitive function in older adults11,12,13,14 , no studies to date have examined the 
 effect of synchronized swimming on cognitive function in older adults . the study participants were recruited from among 23 women practicing synchronized 
 swimming - exercise at a sport club in fukushima - ku , osaka city , japan ( ss group ) . all 
 participants provided written informed consent , after having gained a full understanding of 
 the present study . the study was approved by the ethics committee of the osaka university of 
 health and sport sciences ( approval number 15 - 21 ) . synchronized swimming was performed in a shallow pool from 1.2 to 1.3 meters in depth and 
 the participants were allowed to touch the bottom of the pool with their hands and feet 
 during the performance . participants who had participated in the olympic games or the 
 domestic competitions for seniors were excluded . participants practiced synchronized 
 swimming twice a week for 90 minutes under the supervision of an instructor , who had been a 
 member of the japanese synchronized swimming team . the ages of participants in the ss group 
 ranged from 49 to 85  years ( mean age : 69.8  11.6  years ) , and the duration of synchronized 
 swimming experience ranged from 1 to 39  years ( mean year : 23.9  12.6  years ) . control participants were recruited age - matching women with exercise custom other than 
 synchronized swimming . they were 36 individuals participating in a health promotion program 
 at our university in 2015 , and provided written informed consent as controls ( age range : 
 4977  years ; mean age : 67.0  6.0  years ) . among the participants in the control group , 16 
 participants exercised three or four times a week , 17 exercised once or twice a week , and 3 
 exercised one to three times a month . cognitive functions was compared between the two groups using the japanese version of the 
 montreal cognitive assessment ( moca - j)20 . the moca is a brief cognitive test containing test items related to memory , language , 
 executive function , working memory ( attention ) , visuospatial recognition , abstract thinking , 
 and orientation21 . the sensitivity and 
 specificity of the moca - j in screening for mci has been demonstrated20 . the assessment takes only approximately 10 minutes to 
 complete , and a number of studies have demonstrated the effectiveness of moca - j as a 
 screening tool for mci21,22,23 . total scores of less than 26 points may be indicative of mild cognitive 
 impairment . information on the presence of neurological disease , psychiatric disease , alcoholism , and 
 hospitalization was collected via an interview . unpaired t - tests were used to compare results 
 between the ss group and control group when data were normally distributed , while u tests 
 were performed when the data were not normally distributed . two - sided p values of < 0.05 
 were considered to indicate a statistically significant difference . no significant differences in education level were observed between the control and ss 
 groups ( 12.1  2.0 and 12.2  1.8  years , respectively ) . in addition , no significant 
 differences in total moca - j scores were observed between the two groups ( 22.2  3.6 and 23.2 
  3.1 , respectively ) . twenty - nine participants in the control group and 17 in the ss group 
 scored below 26 on the moca - j and were suspected of having mci ( table 1table 1.comparison of moca - j between the control group and the ss groupscorecontrol group ( n=36)ss group ( n=23)moca - j<2629 ( 80.6)17 ( 73.9)267 ( 19.4)6 ( 26.1)no significant differences are shown between the two groups . moca - j : japanese version of montreal cognitive assessment ; ss : synchronized 
 swimming ) . with regard to moca - j sub - scores , significant differences in delayed recall 
 ( p=0.005 ) however , no significant differences were 
 observed with regard to measures of but not in visuospatial / executive function , naming , 
 attention , language , abstraction , or orientation ( table 
 2table 2.comparison of moca - j sub - score between the control group and the ss groupcontrol group ( n=36)ss group ( n=23)visuospatial / executive function ( 5)3.5  1.03.4  1.0/5naming ( 3)2.9  0.43.0  0.0attention ( 6)4.9  1.14.8  1.0language ( 2)1.6  0.91.7  0.8abstraction ( 2)1.1  0.80.9  0.7delayed recall * ( 5)1.8  1.73.0  1.4orientation ( 6)5.8  0.45.6  0.7total scores22.2  3.623.2  3.1values are shown as the mean  sd . * moca - j : japanese version of montreal cognitive assessment ; ss : synchronized 
 swimming values are shown as the mean  sd . * p<0.005 for the difference between the two groups . no significant differences in years of education or total moca - j scores were observed 
 between the ss group and the control group in the present study . the results of total moca - j 
 scores in the present study align with those of a previous report involving 1,552 
 participants ( mean age : 72  years ; mini - mental state examination score > 24 points ) living 
 in sasaguri , fukuoka prefecture , in which mean the moca - j score was 22.4  3.024 . however , in the comparison of moca - j 
 sub - score in the present study , delayed recall scores , which are considered indicative of 
 recent memory function , were significantly higher in the ss group than in the control 
 group . suzuki et al.25 conducted an 
 exercise - based intervention program that included exercise , calculation , word - chain game , 
 and multiple tasks using a ladder diagram program ( 90 minutes two times per week for 6 
 months ) with participants aged 65  years or older experiencing mci . significant differences 
 in mini - mental state examination , wechsler memory scale - logical memory i , word fluency 
 test - category , and word fluency test - letter scores were observed following this 
 intervention . in synchronized swimming , participants must swim and act in a coordinated 
 manner with other swimmers while performing to music . in other words , the swimmers are 
 required to perform multiple coordinated tasks in an aquatic setting to be more complex than 
 those of the multicomponent exercise program developed by suzuki et al25 . moreover , it has been reported that group music intervention 
 delayed the deterioration of cognitive function , particularly short - term recall among aging 
 adults with mild and moderate dementia26 . performing to music in synchronized swimming might be one of the reason that delayed recall 
 scores were significantly higher in the ss group than in the control group . voelcker - rehage et al.22 reported that 
 not only physical fitness , as indexed by cardiovascular fitness and muscular strength , but 
 also aspects of motor fitness , such as movement speed , balance , motor coordination , and 
 flexibility exhibit associations with executive control and perceptual speed . they further 
 demonstrated physical and motor fitness to be differentially related to various cognitive 
 processes using functional brain magnetic resonance imaging . given that most synchronized 
 swimmers exhibit good cardiopulmonary function , muscle strength , and flexibility27 , it is also possible that enhanced 
 physical fitness may exert direct positive effect on cognitive function . according to a report by suzuki et al.28 , 12 months of multicomponent exercise in particular , positive effects were 
 observed for general cognitive function , immediate memory , and language ability . we 
 therefore consider that synchronized swimming exerted beneficial effects on cognitive 
 function in the participant who experienced synchronized swimming for one year . in conclusion , the results of the present study suggest that synchronized swimming may 
 improve cognitive function in older adults , particularly with regard to recent memory . no relevant disclosures .
[ purpose ] the purpose of the present study was to examine cognitive function in 
 middle - aged and older adults regularly engaging in synchronized swimming - exercise . 
 [ subjects and methods ] twenty - three female synchronized swimmers ranging in age from 49 to 
 85  years were recruited for the present study . 
 the duration of synchronized swimming 
 experience ranged from 1 to 39  years . 
 the control group consisted of 36 age- and 
 gender - matched community - dwelling middle - aged and older adults ( age range : 49 to 
 77  years ) . 
 cognitive function was evaluated using the japanese version of the montreal 
 cognitive assessment ( moca - j ) and compared between the synchronized swimmers and control 
 participants . 
 [ results ] no significant differences in mean total moca - j scores were 
 observed between the synchronized swimmers and control participants ( 23.2  3.1 and 22.2  
 3.6 , respectively ) . 
 twenty - nine subjects in the control group and 17 in the synchronized 
 swimming group scored below 26 on the moca - j , indicative of mild cognitive impairment . 
 significant differences in delayed recall  but not in visuospatial / executive function , 
 naming , attention , language , abstraction , or orientation  were also observed between the 
 two groups . [ conclusion ] the results of the present study suggest that synchronized 
 swimming has beneficial effects on cognitive function , particularly with regard to recent 
 memory .