Catch-up Sleep Research Articles

Sleep health characteristics and positive mental health in Canadian youth: A cross-sectional analysis of the Health Behaviour in School-aged Children study

ObjectivesThis study investigated the associations between specific sleep health characteristics and indicators of positive mental health among Canadian youth in grades 6-10. MethodsWe used cross-sectional data from the Canadian 2017/2018 Health Behaviour in School-aged Children study, a nationally representative sample of Canadian students. Our analyses included 14,868 participants (53.1% girls). We assessed the following self-reported characteristics of sleep health: nighttime insomnia symptoms, sleep duration, problems with daytime wakefulness, and weekend catch-up sleep. Positive mental health measures included self-reported life satisfaction, positive affect, self-efficacy, and self-confidence. Logistic regression models were used to assess associations while controlling for confounders. ResultsParticipants who had no or little nighttime insomnia symptoms, who met sleep duration recommendations, who had no or rare daytime wakefulness problems, and who had no or little weekend catch-up sleep were more likely to report high life satisfaction (range of adjusted odds ratios=1.29-2.50), high positive affect (range of adjusted odds ratios=1.35-3.60), high self-efficacy (range of adjusted odds ratios=1.22-2.54), and high self-confidence (range of adjusted odds ratios=1.28-2.31). Almost all of the associations remained significant in the gender- and age-stratified analyses. ConclusionThe findings suggest that good sleep health is associated with higher odds of positive mental health among Canadian youth in grades 6-10. Further research is needed to understand the temporality of the associations and the underlying mechanisms.

The effects of daylight saving time clock changes on accelerometer-measured sleep duration in the UK Biobank.

We explored the effects of daylight saving time clock changes on sleep duration in a large accelerometer dataset. Our sample included UK Biobank participants (n = 11,780; aged 43-78 years) with accelerometer data for one or more days during the 2 weeks surrounding the Spring and Autumn daylight saving time transitions from October 2013 and November 2015. Between-individual t-tests compared sleep duration on the Sunday (midnight to midnight) of the clock changes with the Sunday before and the Sunday after. We also compared sleep duration on all other days (Monday-Saturday) before and after the clock changes. In Spring, mean sleep duration was 65 min lower on the Sunday of the clock changes than the Sunday before (95% confidence interval -72 to -58 min), and 61 min lower than the Sunday after (95% confidence interval -69 to -53). In Autumn, the mean sleep duration on the Sunday of the clock changes was 33 min higher than the Sunday before (95% confidence interval 27-39 min), and 38 min higher than the Sunday after (95% confidence interval 32-43 min). There was some evidence of catch-up sleep after both transitions, with sleep duration a little higher on the Monday-Friday than before, although this was less pronounced in Autumn. Future research should use large datasets with longer periods of accelerometer wear to capture sleep duration before and after the transition in the same individuals, and examine other aspects of sleep such as circadian misalignment, sleep fragmentation or daytime napping.

Impact of Weekend Catch-Up Sleep on CKD and Albuminuria in Adults: Evidence from NHANES, 2017-2020

Impact of Weekend Catch-Up Sleep on CKD and Albuminuria in Adults: Evidence from NHANES, 2017-2020

Association between Weekend Catch-Up Sleep and Perceived Stress among Adolescents in the Republic of Korea: A Nationwide Cross-Sectional Study.

Association between Weekend Catch-Up Sleep and Perceived Stress among Adolescents in the Republic of Korea: A Nationwide Cross-Sectional Study.

Sleep conditions and sleep hygiene behaviors in early pregnancy are associated with gestational diabetes mellitus: A propensity-score matched study.

To explore the influence of sleep conditions and sleep hygiene behaviors in early pregnancy on gestational diabetes mellitus (GDM) development. This 1:1 propensity-score matched study included 1,216 pregnant women divided into GDM and control groups based on diagnosis via the oral glucose tolerance test at 24-28 gestational weeks. Sleep conditions and hygiene behaviors were evaluated using structural questionnaires, including the Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, and Sleep Hygiene Practice Scale. Univariate and multivariate logistic regression analyses and Spearman's correlation were conducted to identify the associations. After adjusting for baseline clinical characteristics, women with GDM were more likely to have poor sleep quality (adjusted odds ratio [AOR] = 1.585, 95% confidence interval [CI]: 1.261-1.992) and higher scores for subjective sleep quality, latency, duration, efficiency, and sleep disturbances (all P < 0.01). Mild sleepiness (AOR = 1.311, 95% CI: 1.012-1.699) and worrying about not being able to fall asleep (AOR = 1.123, 95% CI: 1.005-1.255) were more likely to occur in the GDM group. Sleep quality and hygiene behaviors such as sleep-irrelevant activities, staying in bed after waking up, weekend catch-up sleep, and overeating before bedtime were significantly correlated with gestational diabetes variables. Poor sleep conditions and specific sleep hygiene behaviors in early pregnancy may be independent risk factors for GDM. This suggests that sleep assessment and behavior education can be used as new approaches for the early implementation of surveillance and prevention of GDM.

Associations between habitual sleep characteristics and cardiometabolic disease risk in corporate executives

ObjectivesCorporate executive job demands may lead to poor sleep habits, increasing their risk for cardiometabolic disease. This study aimed to describe and explore associations between objectively measured habitual sleep characteristics and cardiometabolic disease risk of corporate executives, while accounting for occupational, psychological, and lifestyle factors. MethodsHabitual sleep was measured using wrist-worn actigraphy and a sleep diary over seven consecutive days in 61 (68.3% men) corporate executives aged 46.4 ± 8.7years. A composite cardiometabolic disease risk score was determined using body mass index, waist circumference, blood pressure and fasting glucose and lipid concentrations. Prediction models were built using a backward stepwise selection approach to explore associations between sleep characteristics and cardiometabolic disease risk factors adjusting for occupational, psychological, and lifestyle covariates. ResultsAverage total sleep time was 6.60 ± 0.75 hours, with 51.7% of participants reporting poor sleep quality and 26.2% extending their weekend sleep. Adjusted models showed that lower sleep efficiency (β = −0.25, 95%CI: −0.43; −0.08, P = .006), shorter weekday total sleep time (β = −1.37, 95% CI: −2.41, −0.32; P = .011) and catch-up sleep (β = 0.84, 95%CI: 0.08, 1.60, P = .002) were associated with higher cardiometabolic disease risk scores. Adjusted models also found that shorter average time-in-bed (ß=−2.00, 95%CI: −3.76; −0.18, P = .031), average total sleep time (ß=1.98, 95%CI: −3.70; −0.25, P = .025) and weekday total sleep time (β = −2.13, 95%CI: −3.56; −0.69, P = .025) as well as catch-up sleep (β = 1.67, 95% CI: 0.52; 2.83; P = .012) were all associated with a higher body mass index. ConclusionCorporate executives who compromise sleep duration during the working week may increase their risk for obesity and future cardiometabolic disease.

Interplay of mobile phone dependency and catch-up sleep in South Korean youth: A seven-wave study of two nationally representative cohorts

This study investigated the reciprocal loop between catch-up sleep and mobile phone dependency from late childhood to late adolescence, distinguishing between inter-individual and intra-individual variations. Data from two nationally representative South Korean birth cohorts (N = 4,729, 48.8% female) were collected annually, assessing participants seven times from Grade 4 to Grade 10 or Grade 7 to post-high school. Findings from a cross-lagged panel model (CLPM) and a random-intercept CLPM showed that students who were more dependent on their mobile phones, either compared to others or to their own averages, were likely to report greater catch-up sleep from Grade 4 through Grade 7 in the younger cohort and from Grade 7 through Grade 10 in the older cohort. Likewise, students with greater catch-up sleep, compared to others or to their own averages, tended to rely more on their mobile phones from Grade 4 to Grade 5 in the younger cohort and from Grade 7 to Grade 8 in the older cohort. The CLPM findings further revealed that in the younger cohort, students with higher mobile phone dependency than their peers were more likely to increase catch-up sleep from Grade 7 to Grade 8, and in the older cohort, from Grade 10 to Grade 11. Similarly, higher catch-up sleep led to increased mobile phone dependency from Grade 9 to Grade 10 in the younger cohort, and from Grade 12 to the year post-high school in the older cohort. These patterns suggest consistent tendencies at both inter- and intra-adolescent levels.

Device-measured weekend catch-up sleep, mortality, and cardiovascular disease incidence in adults.

Attempting to recover a sleep debt by extending sleep over the weekend is a common compensatory behavior in the population and is recommended by sleep-focused organizations. However, the purported benefits of catch-up sleep are based on a limited number of cross-sectional studies that relied on self-reported sleep. The objective of this study was to examine the association between accelerometer-derived weekend catch-up sleep and mortality and incident cardiovascular disease (CVD) in adults. A prospective cohort study of UK adults who wore wrist-attached accelerometers was conducted. Weekend catch-up sleep was defined as a longer average sleep duration on weekends compared to weekdays. Participants were categorized into four groups: no weekend catch-up sleep (reference); > 0 to < 1 hour; ≥ 1 to < 2 hours; and ≥ 2 hours difference. Associations between weekend catch-up sleep and mortality and incident CVD were assessed using Cox proportional hazards regression, adjusted for potential confounders. A total of 73 513 participants (sample for mortality) and 70 518 participants (sample for CVD incidence) were included, with an average (SD) follow-up period of 8.0 (0.9) years. In multivariable-adjusted models, weekend catch-up sleep was not associated with mortality (≥ 2 hours group: hazard ratio [HR], 1.17 [95% CI: 0.97 to 1.41]) or incident CVD (HR, 1.05 [95% CI, 0.94 to 1.18]). Dose-response analyses treating catch-up sleep as a continuous measure or analyses restricted to adults sleeping less than 6 hours on weekdays at baseline were in agreement with these findings. Weekend catch-up sleep was not associated with mortality or CVD incidence. These findings do not align with previous evidence and recommendations by sleep authorities suggesting that extending sleep over the weekend may offer protective health benefits.

Can weekend catch-up sleep decrease the risk of cognitive dysfunction in older adults?

This study investigated whether weekend catch-up sleep was related to a decreased risk of cognitive dysfunction in older Taiwanese adults by using self-reported diaries and objective accelerometer measurements. This cross-sectional study enrolled participants who were aged ≥ 65 years and had the capability to walk independently from a medical center in Taipei City, Taiwan, between September 2020 and December 2022. Self-reported sleep diaries and tri-axial accelerometers were used to record and measure sleep-related data for 7 consecutive nights. Weekend catch-up sleep was defined as the mean of weekend sleep time minus the mean of weekdays sleep time. Mini-Mental State Examination (MMSE) was evaluated the risk of cognitive dysfunction. The association between weekend catch-up sleep and the MMSE score was examined using a binary logistic regression model. A total of 215 older adults (53.0% female; 80.5 ± 7.1 years old; 11.6% at risk of cognitive dysfunction) were included. In the adjusted model (adjusted for sex, education level, moderate-to-vigorous physical activity and total accelerometer wear time), both the self-reported sleep diaries (odds ratio [OR] = 0.26, 95% confidence interval [CI] = 0.09-0.69, P = 0.007) and the accelerometer data (OR = 0.27, 95% CI = 0.10-0.70, P = 0.007) indicated that weekend catch-up sleep could decrease the risk of cognitive dysfunction by 73-74%. The study findings suggest that there is an association between weekend catch-up sleep and lower risk for cognitive decline. The causal relationship between weekend catch-up sleep and cognitive function in older adults should be further investigated in a study with longitudinal design.

Examining the connection between weekend catch-up sleep and depression: Insights from 2017 to 2020 NHANES information

BackgroundDepression, a prevalent mental disorder, has shown an increasing trend in recent years, imposing a significant burden on health and society. Adequate sleep has been proven to reduce the incidence of depression. This study seeks to explore how Weekend Catch-up Sleep (WCS) is connected with the prevalence of depression in the American population. MethodsThe National Health and Nutrition Examination Survey (NHANES) provides representative data for the U.S. population. We utilized data from the 2017–2018 and 2019–2020 cycles. Depression was operationally defined as a PHQ-9 score exceeding 10. WCS duration was categorized into five groups: no change in sleep duration (=0 h), decreased sleep duration (<0), short catch-up sleep duration (>0 h, ≤1 h), moderate catch-up sleep duration (>1 h, <2 h), and long catch-up sleep duration (≥2 h). ResultsAmong the 8039 individuals, the distribution of WCS duration was as follows: no change (WCS = 0 h) in 2999 individuals (37.3 %), decreased sleep (WCS < 0 h) in 1199 individuals (14.9 %), short catch-up sleep (0 h < WCS ≤ 1 h) in 1602 individuals (19.9 %), moderate catch-up sleep (1 h < WCS < 2 h) in 479 individuals (6.0 %), and long catch-up sleep (WCS ≥ 2 h) in 1760 individuals (21.9 %). Acting by adjustment for all covariates in a multiple regression analysis, we discovered that persons with 1 to 2 h of weekend catch-up sleep had a substantially low prevalence of depression concerning those with WCS = 0 (OR 0.22, 95 % CI 0.08–0.59, P = 0.007). ConclusionThe prevalence of depression in individuals engaging in weekend catch-up sleep for 1 to 2 h is lower than those who do not catch up on weekends. This discovery on the treatment and prevention of depression provides a new perspective. However, further prospective research and clinical trials are needed for a comprehensive investigation.

0716 Longitudinal Associations of Weekend Catch-up Sleep and Sleep Ability with Mortality in Middle-aged Adults

0716 Longitudinal Associations of Weekend Catch-up Sleep and Sleep Ability with Mortality in Middle-aged Adults

Circadian misalignment proxies, BMI, and chronic conditions: the role for weekday to weekend sleep differences.

To evaluate whether social jet lag (SJL) and weekend catch-up sleep (CUS), proxies of circadian misalignment, were associated with BMI and chronic conditions. Participants (n = 2,050,18-65y) were part of a virtual cross-sectional and population-based research. We examined CUS and SJL as continuous and categorical (< 1h,1-2h, > 2h). Linear regression analyses were performed to assess the differences in BMI (outcome) associated with CUS and SJL. Restricted cubic splines were performed to explore the shape of the relationship between weekday-to-weekend variability in sleep duration, midpoint, wake time, and bedtime. Logistic regression models were used to estimate ORs(95%CIs) for chronic conditions and overweight related to CUS and SJL. Analyses were adjusted for sleep duration, biological and behavior-related variables. We found a positive association of SJL and CUS with BMI. The effects remained even after adjustment for weekly sleep duration and demonstrated a proportional increase with the magnitude of sleep variability. Among participants with SJL > 2h, BMI increased by 2.29kg/m2 (95%CI:0.84;3.74,p:0.002). They also had 129% higher odds of chronic conditions (95%CI:1.16;4.52, p:0.01) and 119% higher odds of overweight (95%CI: 1.20;3.98,p:0.01). Individuals with CUS > 2h presented 78% higher odds of overweight (95%CI:1.27;2.50,p:0.001) and an increase of 1.61kg/m2 in BMI (95%CI: 0.81; 2.40,p < 0.001). Our findings, which demonstrate that even a slight weekend sleep extension and variability of just 1h is associated with higher values of BMI, suggest incorporating measures for sleep consistency and regularity into clinical protocols and public health guidelines to prevent and treat obesity and related diseases.

Association between weekend catch-up sleep and depression of the United States population from 2017 to 2018: A cross-sectional study

Insufficient sleep on weekdays has become a societal norm, and studies have shown that sleep deprivation increases the risk of depression. Although individuals often resort to weekend catch-up sleep (CUS) as a compensatory measure, the present evidence supporting its efficacy in mitigating the risk of depression is limited. This article attempts to explore the relationship between CUS and depression. In this study, a total of 5510 participants were included, characterized into two groups: nondepressed (n = 5051) and depressed (n = 459), with data extracted from the National Health and Nutrition Examination Survey (NHANES). Compared with people without CUS, those practicing CUS exhibited a significantly lower risk of depression (OR = 0.81, P = 0.048). In subgroup analysis, this reduction effect was only observed in males (OR = 0.70, 95 % CI 0.05 to 0.99, P = 0.04), middle-aged (>40, ≤60) (OR: 0.57, 95 % CI: 0.40 to 0.81, P = 0.002), married or living with parents (OR: 0.61, 95 % CI: 0.44 to 0.86, P = 0.004), groups with three or more family members (OR: 0.69, 95 % CI: 0.52 to 0.93, P = 0.01), and individuals without alcohol intake (OR: 0.24,95 % CI: 0.09 to 0.67, P = 0.006). Therefore, in the realm of depression treatment, doctors may consider advising patients to get adequate sleep on weekends as part of their overall treatment plan. At the same time, individuals can also choose weekend sleep as a proactive strategy for regulating their psychological status.

Association between weekend catch-up sleep and depressive symptoms in American adults: Finding from NHANES 2017–2020

BackgroundThe effect of weekend catch-up sleep (WCS) on depressive symptoms is inconsistent among different populations, with limited evidence in Americans. Therefore, we aimed to investigate the association between WCS and depressive symptoms in American adults. MethodsWe recruited 7719 participants from the National Health and Nutrition Examination Survey (NHANES) 2017–2020. Information on sleep duration and depressive symptoms were assessed by several self-reported questions and Patient Health Questionnaire-9 (PHQ-9), respectively. Then, WCS duration was calculated as weekend sleep duration minus weekday sleep duration, and WCS was further defined as WCS duration >0 h. Survey designed regression analyses were used to assess the association of WCS and depressive symptoms. ResultsIn fully adjusted multivariate logistic regression models, the odds ratio (95 % confidence interval) for depressive symptoms and the β (95 % confidence interval) for PHQ-9 score in response to WCS were 0.746 (0.462, 1.204; P = 0.218) and −0.429 (−0.900, 0.042; P = 0.073), respectively. Besides, the smooth relationship presented L-shaped, and only WCS duration of 0–2 h was statistically significantly associated with depressive symptoms or PHQ-9 score. Subgroup analyses showed that the negative associations were stronger among men, adults younger than 65 years, and those with short weekday sleep duration (P for interaction <0.05).Limitations.The cross-sectional design limits the capability for causal relationship between WCS and depressive symptoms. ConclusionsThis study suggests that moderate WCS is associated with reduced odds of depressive symptoms, which provides additional epidemiological evidence for the effects of sleep on depressive symptoms.

IDF23-0352 Association between weekend catch-up sleep and cardiovascular disease risk: Cross-sectional study

IDF23-0352 Association between weekend catch-up sleep and cardiovascular disease risk: Cross-sectional study

The early-stage impacts of shock events on adult sleep: Lessons from the COVID-19 pandemic.

The present study aims to estimate the early-stage association of the coronavirus disease 2019 (COVID-19) pandemic with sleep duration, 4months after the initial outbreak, at a national level. Using the China Family Panel Studies in 2018 and its follow-up in 2020, 16,563 adult participants were analyzed in our study. The first wave transmissibility of the COVID-19 pandemic in mainland China was used as a quasi-natural experiment. The difference in difference method was employed to compare variations across participants interviewed before or after the pandemic and between groups from provinces with different COVID-19 severity. The study observed a decline in workday sleep duration among adults, regardless of their employment status. Specifically, working adults experienced a significant decrease in sleep duration on work days (-1.54, 95% confidence interval -2.16 to -0.92), alongside an increase on work-free days (2.41, 1.56-3.24), leading to a wider sleep discrepancy in sleep patterns (3.95, 3.31-4.59). Noteworthy, working-age adults (-2.00, -2.79 to -1.22) and males (-3.31, -4.31 to -2.30) exhibited greater sleep decreases on work days, whereas females exhibited a more pronounced disparity in sleep patterns (6.18, 4.73-7.63) between work and work-free days. The pandemic is significantly associated with prolonged changes in adults' sleep duration, including sleep decreases on work days and catch-up sleep on work-free days for working adults. To prepare for future global emergencies, the government may need to promote resilience to mitigate the pandemic's adverse impacts on the working population. Guaranteeing adequate sleep among working adults and reducing sleep debt should be prioritized in such efforts.

Association between weekend catch-up sleep and the risk of prediabetes and diabetes: A cross-sectional study using KNHANES

BackgroundThe objectives of this cross-sectional study were to explore the relationship between weekend catch-up sleep (WCUS) and the risk of prediabetes/diabetes and to assess how this risk varies based on WCUS duration, using a large population sample in South Korea. MethodsData were sourced from the 2021 Korea National Health and Nutrition Examination Survey, involving 2472 subjects aged 30 years and above, employed, and not using blood glucose-lowering medications. Prediabetes/diabetes risk was examined based on the presence of WCUS. Participants were categorized into four groups by WCUS duration (< 1, ≥ 1 and < 2, ≥ 2 and < 3, and ≥ 3 h) to evaluate the prediabetes/diabetes risk across varying WCUS durations. ResultsNo significant difference in prediabetes/diabetes risk was observed between the WCUS and non-WCUS groups. In subgroup analysis, a WCUS duration of 1 to 2 h was related to a lower odds ratio of prediabetes (aOR = 0.618, 95% CI = 0.382–0.999), while 3 h or more was associated with a higher odds ratio of diabetes (aOR = 3.098, 95% CI = 1.561–6.149). ConclusionsIn individuals who experience insufficient sleep during weekdays and manage to achieve the optimal average sleep duration of 1 to 2 h of WCUS, WCUS was associated with improved blood glucose regulation. However, compensating for excessive weekday sleep deprivation with WCUS of 3 h or more was associated with impaired blood glucose regulation.

Association of sleep timings, duration, consistency, and chronotype with premyopia and myopia among Indian children.

To explore the association of sleep timings, duration, consistency, and chronotype with premyopia and myopia among Indian children. This hospital-based cross-sectional study included 453 children, aged 6-12 years. Two myopia participants were selected for each individual with the corresponding premyopia or emmetropia. All children underwent cycloplegic autorefraction and ocular biometric tests. The Children's Sleep Habits Questionnaire (CSHQ) and parental information on behavioral habits were used to assess the association of sleep parameters with myopia and premyopia using logistic regression models. Both myopia and premyopia exhibited significant late bedtime, short sleep duration, early wakeup time on only weekdays, and longer weekend catch-up sleep than emmetropia children (p < 0.05). In multivariate analysis, late bedtime (more than 24:00 a.m.) on weekdays (Odds ratio, OR = 3.63, 95% CI [0.74, 8.68]) as well as on free days (OR = 1.04, 95% CI [0.02, 8.08]); and early wake-up time only on weekdays (5:00-6:00 a.m., OR = 2.16, 95% CI [0.24, 6.76] and 06:00-07:00 a.m., OR = 2.42, 95% CI [0.51, 8.44]) were associated with increased risk of myopia (all p < 0.05) but not premyopia. After adjusting the confounding factors, when each of the eight CSHQ subscale components was analyzed, only bedtime resistance, night waking, and daytime sleepiness scores were significantly associated with a higher risk for premyopia and myopia (p < 0.05). The sleep quality components, including bedtime resistance, night waking, and daytime sleepiness, equally involve a higher risk for myopia as well as premyopia.

Weekend sleep extension (catch-up sleep) is associated with lower incidence of coronary calcium score: the ELSA-Brasil study

Weekend sleep extension (catch-up sleep) is associated with lower incidence of coronary calcium score: the ELSA-Brasil study

Association between weekend catch-up sleep and cardiovascular disease: Evidence from the National Health and Nutrition Examination Surveys 2017-2018.

This study aimed to investigate the relationship between the weekend catch-up sleep duration and cardiovascular disease prevalence among adults in the United States. Cross-sectional study. The United States. Participants from the 2017-2018 National Health and Nutrition Examination Survey (NHANES) who were 20years old or older (n=3400). Sociodemographic characteristics, sleep duration (weekday and weekend), and the presence of cardiovascular disease, hypertension, and diabetes were recorded for all participants. Weekend catch-up sleep was defined as sleeping 1hour longer on weekends than on weekdays. Adjusted multivariable logistic regression analysis was conducted to assess the relationship of weekend catch-up sleep with cardiovascular disease. Participants with cardiovascular disease had shorter weekend catch-up sleep than those without cardiovascular disease (P<.01). Participants with weekend catch-up sleep had a lower prevalence of cardiovascular disease (P<.01) than those with no significant change in weekend sleep duration. An adjusted multivariate logistic regression analysis showed that weekend catch-up sleep duration was significantly associated with the prevalence of angina (P=.04), stroke (P<.01), and coronary heart disease (P=.01). Weekend catch-up sleep was associated with reduced cardiovascular disease prevalence when the weekday sleep duration was <6hours (P<.01). A stratified analysis of participants with <6hours of sleep on weekdays showed that weekend catch-up sleep duration (>2hours) was associated with reduced prevalence of cardiovascular disease (P=.01). Our findings indicate that weekend catch-up sleep duration of >2hours is strongly associated with reduced cardiovascular disease prevalence when the sleep duration is <6hours on weekdays.