Children’s Health, Wellbeing and Academic Outcomes over the Summer Holidays: A Scoping Review

Background: The school day provides a supportive and stimulating environment that may protect children and adolescents (5–18 years) from behaviours that are adverse for health and wellbeing. Objective: To review the literature regarding changes in children’s academic achievement or overall wellbeing during the extended school summer break and evaluate if the outcomes are different for children experiencing disadvantage. Methods: The peer-reviewed literature was searched across six electronic databases for studies tracking changes in any academic, health or wellbeing outcome in children over the summer holidays. Studies were screened in duplicate for inclusion. Data were extracted using a standardized data extraction form. Outcomes were coded as decline (suggestive or significant), increase (suggestive or significant) or mixed/neutral and then compared to the school year or according to disadvantaged. Results: Seventy-six studies (n = 14,230,846 participants) were included. Strong evidence was found of a decline in academic outcomes and increases in adiposity, sedentary behaviour and screen time. There was moderate evidence of declines in cardiovascular fitness and physical activity. These patterns were magnified for disadvantaged children. Limited data were available on muscular fitness, sleep, diet quality and social, emotional or mental wellbeing. A total of 80% of studies were from the United States. Most data were from children 12 years of age and younger. Conclusions: Over the summer break, children’s academic and health outcomes decline. Children experiencing disadvantage display magnified losses that warrant further investigation. The summer holidays present an opportunity to improve children’s health and wellbeing.


Introduction
In addition to academic achievement, school plays an important role in children's health and wellbeing.Schools often have a positive influence on children's emotional, social and psychological development [1,2] as wellbeing is supported through engagement with teachers, peers and the school environment [2].Furthermore, the school day is governed by curricula and policies regarding physical activity (PA) and diet, which enable children to display healthier patterns of behaviours relative to non-school days such as weekends and holidays [3][4][5].Therefore, the absence of school (e.g., on weekends and holidays) has the potential to impact a wide range of health and wellbeing outcomes.
Summer holidays are the longest break from school and can last from six weeks (across Asia and Australia) to over three months in some parts of Europe and the US [6].The education literature has long reported the phenomenon of the "summer slide", where students experience a decline in academic achievement during the extended summer break [7].Emerging evidence suggests that children's obesogenic behaviours intensify on holidays and weekends, leading to weight gain [5,8], with evidence that the prevalence of childhood obesity increases exclusively in the summer [9][10][11].Furthermore, evidence suggests that for some children, losing the connection and social support of school leads to feelings of loneliness and anxiety over the summer holidays, detrimentally affecting mental health [12].Children disadvantaged by race, low income or social status may be affected to a greater extent.Outside of the school environment, low-income families face specific barriers to providing safe and stimulating care for children, resulting in different, and less enriching, holiday experiences for disadvantaged children [12,13].Disadvantaged children are therefore particularly susceptible to worsening mental health over the summer [14], but the extent of these challenges remains unclear.
Cooper and colleagues' seminal paper [7] was the first to comprehensively review the literature regarding summer learning loss over a quarter century ago and demonstrated a summer decline in academic achievement that disproportionately affected disadvantaged children.Since then, it has been proposed that the accumulating effects of multiple summer holidays lead to a widening of the academic achievement gaps between the rich and poor [15].Currently, there is debate whether inequality in achievement scores increases [16], remains stable or decreases [17] when school is not in session.
Previous research has mainly examined children's weight gain or fitness decline over the summer without adopting a holistic lens [5,[9][10][11]18].A few narrative reviews have described weight and fitness changes during the summer, emphasising attempts to address these issues [5,10,18].These reviews underscored uncertainties about the most vulnerable populations, with some evidence suggesting disadvantaged children bear a disproportionate burden.These disparities hint at summer breaks exacerbating health inequalities between socio-economic groups and the existing literature reviews seem to overlook children's social, emotional, or mental wellbeing during the summer.
In this context, our objective was to holistically evaluate current evidence across multiple domains during the summer.We hope this review will guide future research trajectories and highlight pivotal intervention areas.We conducted a scoping review to answer the following questions regarding changes in children's health, wellbeing and academic achievement over the summer holiday period and the associations with socioeconomic disadvantage: 1.
What are the geographical and historical trends in the literature related to children's academic, health and wellbeing outcomes over the summer?2.
How do children's academic, health and wellbeing outcomes change over the summer holiday period?3.
Do these changes differ according to the level of disadvantage in children?

Methods
A review protocol was developed a priori using the framework of the Joanna Briggs Institute [19], informed by the Synthesis Without Meta-analysis (SWiM) guidelines [20], and prospectively registered with Open Science Framework [21].The review is reported in accordance with the PRISMA-ScR guidelines [22].

Eligibility Criteria
This scoping review aimed at providing a broad overview of the existing literature.The PCC (Population, Concept, Context) framework was used to structure the inclusion criteria: studies were considered if they focused on school-aged children aged 5 to 18 years (Population), covered any aspect of health, wellbeing, or academic outcomes (Concept) and pertained specifically to the summer holiday period, aiming to delineate changes over the summer or differences relative to the school year (Context).The research designs either tracked changes over the summer period through longitudinal data or provided comparative measures between the summer holidays and the school year.All the included Children 2024, 11, 287 3 of 28 studies had a minimum of 100 participants and were published in English between the year 2000 and 5 September 2022.Studies were excluded if they were from the grey literature, failed to meet the inclusion criteria or were not published in English (a detailed description of the review's inclusion criteria is presented in Supplementary Table S1).
To ensure a multi-disciplinary approach, we performed a simultaneous search across six major academic databases: Medline, PsychInfo, Embase, JBI (OVID), ERIC (ProQuest) and Scopus, with the searches completed on 5 September 2022.The search strategy for this review was designed to be highly comprehensive, given the study's aim to provide an extensive overview across a broad range of the literature pertaining to education (academic outcomes), health (physical health and health behaviours) and psychology (social, emotional and mental wellbeing).The strategy was developed in close consultation with an academic librarian and refined by preliminary searches.Subject headings, keywords and MeSH using the population descriptions "children" and "adolescent" were combined using the operator AND with keywords describing the time period "summer" adjacent to the term "holidays" or "vacation".To maintain the review's focus, we systematically excluded studies related to COVID-19 by employing the NOT operator with the terms "pandemic", "COVID-19", and "SARS-CoV-2" (a detailed example of the Medline search strategy has been provided in Supplementary Table S2).
References were managed and duplicates removed using Endnote (Endnote 20, Clarivate, Philadelphia, PA, USA).To determine the eligibility of studies for this review, title and abstract screening was followed by full-text screening: both rounds were conducted in duplicate by the main author (EE) and a second author (AM, AW, RV) using Covidence software (Veritas Health Innovation, Melbourne, Australia, available at www.covidence.org) and disagreements were resolved by consensus (by both authors).For the sixty-nine studies that met the inclusion criteria, the reference lists were searched (by EE) for further relevant studies and sixteen further studies identified.

Data Extraction
Data extraction was completed using Covidence by the main author (EE) with a charting form, informed by the Joanna Briggs Institute [19], developed collaboratively by the entire authorship team and rigorously piloted prior to use.Data extraction was completed in duplicate for 20% of the studies, with discrepancies solved by consensus before the completion of data extraction by the main author, who discussed uncertainties with another author.The data extraction fields included study characteristics (author, year, country of origin, sample size), participants' demographics (age, sex, measures of disadvantage) and data items for academic outcomes (e.g., reading, mathematics), physical health (e.g., body composition, fitness), health behaviours (e.g., PA, sedentary behaviour, diet, sleep, screen time), mental health (e.g., anxiety, depression) or social-emotional function (e.g., antisocial behaviour).During extraction, changes in these outcomes were coded in terms of the direction of change (increase or decrease) and amount of change (significant or suggestive) in the following manner: change over the summer was coded as significant if it reached the study's own parameters of statistical significance, or no change if it did not.Changes not tested for significance were categorized as suggestive.

Certainty of Evidence
The certainty-of-evidence grading was adapted from previous scoping reviews [23] based on the consistency of the findings when at least five studies were available.When at least 75% of the findings were consistently in the same direction, the evidence was graded as "Strong".A "Moderate" grade was assigned when most of the studies (but <75%) found a pattern in the same direction.When approximately equal studies indicated a change in conflicting directions, a "Mixed" grade was applied [23].Outcomes with insufficient data (<5 studies) were designated as "Limited" grade.

Synthesis of Results
The data synthesis adhered to the PRISMA-ScR extension [22] and the SWiM guidelines [20].Participant age was categorized based on standard educational groups: lower primary (ages 5-7), middle primary (ages 8-10), upper primary/middle school (ages 11-13), and high school (ages 14+).Studies were assigned to these categories based on the predominant age of the participants, or to more than one category when the distribution was evenly spread across multiple categories.
Socio-economic status (SES), either direct or by proxy, was the primary determinant of disadvantage used in this review, while other secondary markers (e.g., race/ethnicity) were used in the absence of SES data.The SES measures included individual/family metrics (e.g., parental education, household income) or broader metrics such as school location or eligibility for school meal subsidies.
The outcomes were primarily sorted into four domains: academic, physical health, health behaviours and emotional-social and mental wellbeing combined.Within these groups, finer analyses were conducted where uniformity in the outcomes allowed.A votecounting method was adopted to integrate the findings.Changes were coded as better or worse over the summer.When a study reported multiple significant and suggestive changes in a consistent direction, the more robust value was retained.Studies with conflicting findings (e.g., opposite findings for subgroups with no overall measure) were counted as mixed/no difference.The impact of the summer holidays on disadvantaged children, when presented, was specifically delineated.

Results
A total of 11,870 studies were identified, with 3529 duplicates removed before the title and abstract screening (n = 8341).In situations where multiple reports emerged from a single study due to varied analyses or additional years, these were considered duplicates to prevent oversampling bias and consolidated into one study for analysis.Consequently, 76 studies, derived from 85 reports, were included The evidence selection sources are presented in the PRISMA-ScR flow diagram (Figure 1).

Characteristics of Included Studies
The studies included in this review used either primary or secondary data sources, examples of which included the Early Childhood Longitudinal Study, the Northwest Evaluation Association's Growth Research Database, the Baltimore Beginning School Study, or administrative records.Out of these, 40 studies collected data for a single summer, 34 spanned multiple summers and 2 studies contrasted behaviours in the summer with the school term.A total of 68% (51/76) compared summer changes with school year changes.The characteristics of included studies are detailed in Table 1.
A total of 90 outcomes were reported in the 76 included studies.Academic outcomes were the most frequent, appearing in 55% (n = 42) of studies.Physical health was covered in 35% (n = 27), while 20% (n = 15) discussed other health behaviours.Due to the small number of studies (n = 4: 5%), social, emotional or mental wellbeing were grouped together.All the studies encompassed both genders, and there was considerable overlap in the age categories, with 34% (n = 26) of studies covering multiple age groups.Most research targeted children under the age of 12 years, from the lower primary (n = 41 studies: 54%, from school entry to second grade: ages 5-7 years) and middle primary age groups (n = 40 studies: 53% in grades three through five: ages 8-10 years).Middle school students were the subjects in 27 (36%) studies, while high school students were under-represented as participants in only 4 studies (5%).Ages were not reported in three studies (4%).Twenty-nine studies (38%) stratified results for disadvantaged populations, based on either socio-economic status or race/ethnicity.

Reading and comprehension:
Growth rate (MAP).

Characteristics of Included Studies
The studies included in this review used either primary or secondary examples of which included the Early Childhood Longitudinal Study, th Evaluation Association's Growth Research Database, the Baltimore Begi Study, or administrative records.Out of these, 40 studies collected data summer, 34 spanned multiple summers and 2 studies contrasted beha summer with the school term.A total of 68% (51/76) compared summer school year changes.The characteristics of included studies are detailed in T

Academic Outcomes over Summer
The academic outcomes explored included literacy (n = 25 studies; encompassing reading ability, comprehension, vocabulary, and language); numeracy (n = 7 studies; covering math concepts, problem solving, reasoning); and others, including combined achievement tests, cognition (focusing on working memory) or academic progress (n = 14).Forty-six academic outcomes were reported from twenty-seven studies (some studies reported multiple outcomes) and are presented in Figure 3.

Academic Outcomes over Summer
The academic outcomes explored included literacy (n = 25 studies; encompassing reading ability, comprehension, vocabulary, and language); numeracy (n = 7 studies; covering math concepts, problem solving, reasoning); and others, including combined achievement tests, cognition (focusing on working memory) or academic progress (n = 14).Forty-six academic outcomes were reported from twenty-seven studies (some studies reported multiple outcomes) and are presented in Figure 3.
Regarding muscular fitness, one study showed a summertime decrease [32] and two an increase [43,49].All the flexibility results (2/2) were neutral [26,37,43].Overall certainty of evidence: Strong evidence that children's adiposity increases over the summer holidays.Moderate evidence of a decrease in CVF over the summer, especially when compared to the school year; evidence regarding changes in muscular fitness or flexibility is limited.The evidence suggests a decline in children's physical health during the summer holidays.one study demonstrating an improvement [43].These findings were further explored within the full-year pattern (not shown in Figure 4): Ten studies compared CVF changes across the summer to changes over the school year (not shown in Figure 4): Seven studies (78%) found CVF was worse over the summer [26,31,37,52,80,86,[99][100][101], one Hungarian study found no difference [93] and one Austrian study found summer improvements [43].Regarding muscular fitness, one study showed a summertime decrease [32] and two an increase [43,49].All the flexibility results (2/2) were neutral [26,37,43].Overall certainty of evidence: Strong evidence that children's adiposity increases over the summer holidays.Moderate evidence of a decrease in CVF over the summer, especially when compared to the school year; evidence regarding changes in muscular fitness or flexibility is limited.The evidence suggests a decline in children's physical health during the summer holidays.
Two studies (2/3, 67%) measuring sleep found an increased duration over the summer holidays [55,100] and one found a decrease [100].Diet quality was demonstrably worse in two studies (2/3, 67%) [96,100] and mixed in another [93] (Figure 6).Overall certainty of evidence: Strong evidence that SB and screen time increase in the summer; moderate evidence that PA declines (MVPA and LPA).Evidence regarding changes in sleep and diet quality is limited.

Mental, Emotional, and Social Wellbeing
Four studies reported on emotional and social outcomes, with no studies addressing mental health outcomes.Rulison and colleagues examined the relationship between adjustment and peer group aggression and reported that victimization increased in the summer relative to the school year, with the aggression level of the affiliated peer group highlighted as an important factor [87].Light et al. focused on antisocial actions and experiences of social victimization and found an increase in antisocial behaviour over the summer, with a decline at the start of the school year [68].Downey et al. considered how the summer period affected existing disparities in mental wellbeing between advantaged and disadvantaged groups and pinpointed persistent gaps between high and low socioeconomic status (SES) groups for behaviours including self-control and interpersonal skills.These disparities, evident from kindergarten onset and evident through 2nd grade, did not seem to change over the summers [41].Sallis et al. measured changes in self-efficacy alongside changes in PA over the summer holidays [88].The reduction in MVPA by 14 min/day did not correlate with children's self-efficacy, which remained unchanged over the summer.Decreased social interaction was associated with less enjoyment of PA and influenced time spent on PA.Overall certainty of evidence: Limited.

Summertime Changes and Disadvantage
Twenty-nine studies presented stratified results for disadvantaged populations, based on either socio-economic status or race/ethnicity.Overall, the results showed similar patterns of summertime decline as shown for the general child population, but the patterns of loss were relatively greater for disadvantaged children.For example, amongst the studies that measured the academic outcomes of both disadvantaged and advantaged children and presented stratified results, there was a strong pattern of summertime academic loss in literacy for disadvantaged children that was not evident in the general population and comparative achievement across all the outcomes was consistently worse for disadvantaged children (Figure 7).A summary of the findings related to disadvantage across all the outcomes is presented in Supplementary Table S3.
advantaged children and presented stratified results, there was a strong patt summertime academic loss in literacy for disadvantaged children that was not evi the general population and comparative achievement across all the outcome consistently worse for disadvantaged children (Figure 7).A summary of the fi related to disadvantage across all the outcomes is presented in Supplementary Tab

Discussion
This review of children's health and wellbeing aimed to synthesize the current evidence regarding summertime changes across a wide variety of domains.We explored geographical and historical trends in the research, described how children's academic, health and wellbeing outcomes changed over the summer holidays and examined trends for children experiencing disadvantage.The findings revealed a historical focus on academic outcomes, with data being predominantly derived from US studies.In the past decade, studies from outside the US have increased, with growing attention focused on health and health behaviour outcomes.Our review highlighted summertime numeracy declines for all children, while disadvantaged children also experience declines in literacy.Children's physical health is worse across the summer holidays, with evidence of declines in fitness and increases in adiposity compared to the school year.Clear patterns emerged of increased sedentary and screen time in the summer holidays and health behaviours are relatively worse for disadvantaged children.There was a lack of data regarding children's social, emotional and mental wellbeing across the summer holidays.
The decline in numeracy demonstrated here is congruent with findings from two recent review studies of academic outcomes over the summer (both published in 2023), which similarly found a decline in numeracy and mixed literacy results [107,108].Numeracy is commonly measured using standardized tests of mathematics, which have been criticized for the emphasis on procedural knowledge over deeper conceptual knowledge [109].Procedural knowledge (e.g., knowing how to perform problem-solving steps in the correct order) relies on memorization and repetition and is therefore more susceptible to declines from gaps in practice.Children may practice procedural literacy skills in the summer through independent reading and journaling (and even interactive video games), whereas math may be less integrated into the daily routine [110].
Children's physical health is better during the school year compared to the summer holidays.The summertime increases in fatness and decreases in fitness displayed here have been previously observed in the US and internationally, with the magnitude of effects demonstrably greater in regions where the summer holidays are longer [31, 49,92,100,111] compared to where the breaks are shorter [112].Left unaddressed, these summertime declines in physical health could accumulate.This is concerning because childhood obesity is a major, global public health concern with life-long consequences [113] linking it with a variety of health problems, including type 2 diabetes, heart disease and depression [114].Physical fitness is considered one of the most important markers of health and a predictor of illness [115], and low CVF in childhood is related to increased adiposity and cardiovascular disease risk factors, poorer mental health and lower academic achievement [115].Although the aetiology of summer weight gain is not clear, the physiology of weight gain is well established to be related to a positive energy balance in summer due to changes in key behaviours: Diet, PA, sedentary behaviour, screen time and sleep [5,10,18].
Sedentary behaviour and screen time were clearly greater during the summer.This is consistent with the Structured Days Hypothesis [3], which posits that on school days, which are purposefully planned and supervised by adults, it is easier for children to display healthier patterns of behaviour than it is on unstructured days like weekends and holidays.More sedentary behaviour means less energy expenditure over the summer and, although data on diet in summer were missing here, there is recent evidence that children tend to display worse dietary habits over the summer holidays [112] and when engaged in sedentary behaviours (e.g., snacking on energy dense, high-fat, high-sugar food and drinks), which may further tip the energy balance towards weight gain [116].
Our review showed mixed results for PA, hinting at unexplored nuances within specific subgroups (e.g., gender, age, weight status [18]).Factors like urban vs. rural settings [5] and socio-economic status can influence holiday activities [18], and detailed data on participation in organized sports or summer programs were often not tracked in the included studies.
Our review extends the current evidence base by exploring trends in each outcome for disadvantaged children.Regarding academic outcomes, disadvantaged children experienced overall sharper declines and decreases in literacy that were not apparent in the general population.These trends are concerning because summer holiday declines can accumulate and influence future curriculum pathways and career opportunities, which would limit opportunities for upward mobility through socio-economic classes [24].Entwisle and colleagues [117] proposed the "faucet theory" to explain the comparatively worse academic outcomes over the summer for disadvantaged children.They proposed that school turns on a resource faucet for all children, which essentially turns off over the summer.While middle-to high-income families have the resources to provide enriching experiences that replace school's influence, poorer families do not.The concept behind the faucet theory may also apply to health behaviours, which then impact physical health.
The family environment is an important determinant of children's health and wellbeing.All health behaviours were worse for disadvantaged children (noting that only the US studies made these comparisons).Low-income families face cost, childcare and emotional pressures over the summer holidays [118].Difficulty finding affordable childcare results in children spending time unsupervised [119], and when left to their own devices, children self-select less healthy snacks [120].Consecutive summer days in these circumstances influence children's physical health.The observed differences in time use between social classes over the summer have led Weaver and colleagues [5] to propose the Health Gap Hypothesis, whereby families in the middle/upper income brackets display fewer obesogenic behaviours over the summer than children from low-income backgrounds.As a result, disadvantaged children gain weight and lose fitness at a faster rate, which increases the health disparity between the rich and poor.
This review has important strengths.This is the first ever review to bring together diverse academic, health and wellbeing outcomes in a single paper.A comprehensive search strategy was employed to cover a wide-ranging literature base, spanning the academic, health and psychology domains, enabling a complete picture to be painted of these changes in children across the summer.This review also explored trends related to socioeconomic and sociodemographic disadvantage, which helps to highlight when exacerbation of health and achievement disparities could occur.
Most of the study's limitations arose from the literature base itself.Over three quarters of the studies were from the United States, with limited data from other world regions (particularly the Asia-Pacific and Africa).Our review did not explore differences according to age, which may be an important factor in summer holiday health [10].Given the sparse representation of high-school participants, applying these findings to older adolescents warrants caution.In practice, there is difficulty measuring the summer period, as children are more accessible to researchers during the school period, but inclusion of in-term data can mask some summer effects.Other considerations pertain specifically to measuring changes in children's body weight over time, as it can be challenging to delineate normal healthy growth from unhealthy or excessive increases in body weight.To address this concern regarding adiposity and CVF, where the studies provided further measures (i.e., a third time point) we compared the changes in summer to the school period and found the same consistent pattern of health declines.Finally, given the breadth of this scoping review, it was not feasible to search and include grey literature sources; however, the reference lists of included studies were searched and the authors contacted to identify other relevant studies, which is considered an effective and suitable method of addressing publication bias [121].

Implications
The pause or decline in learning rates experienced by disadvantaged children seems to accumulate, contributing a great deal to overall achievement inequality [122].Despite extensive public health efforts, the incidence of childhood obesity continues to rise and differentially effect certain socio-economic groups [123].While health interventions delivered in schools have been convenient, it seems some of the benefits gained are offset by the deterioration over the summer [5,124,125].In this context, our review suggests that summertime interventions could improve children's academic and health outcomes.
Furthermore, the different summer experiences between the rich and poor may underlie the greater academic and health losses evident for disadvantaged children revealed in this review.Disadvantaged families face challenges in providing safe and enriching care over the summer [118], which could influence the amount of obesogenic behaviours these children display.Structured summer programming is one potential solution to help children and families deal with the challenges of the summer break.Summer programs would provide both childcare for carers (thus providing the primary caregiver(s) with respite and the ability to continue paid employment) while providing a stimulating environment to promote healthy behaviours in children and offer one potential solution.
Summer programs already exist globally, in a variety or structures and formats.For example, summer camps are common in the US but are perhaps under-utilized in other parts of the world.Typical US summer camps follow either an overnight format (where children spend multiple nights away from home) or day camps whereby activities and meals are provided during the day and children return home each evening.Such camps are run by a range of different stakeholders, including private, religious and not-for-profit groups, and cater to various populations (e.g., general, low-income, special needs).Alternatively, in Belgium, local councils collaborate with residents to run free "Play Streets" that provide a free space and activities for children to play with and interact with others [126].Understanding the key elements of such programs that make them effective (and if the effects are different for disadvantaged children) remains an area for further exploration.Despite the demand for such programs, cost is a common and significant barrier to access for low-income families [127].Therefore, the development and successful implementation of summer programs will require policy makers, providers and stakeholders (i.e., local governments, schools, children and parents) to design programs that cater to the needs of their communities and give special consideration to making programs acceptable and feasible to the most at-risk populations.

Figure 2
Figure 2 displays the temporal trends in the research.Overall, there has been a steady increase in the volume of studies conducted across 12 years (2000 to 2022).Out of the total of 76 studies, 80% (n = 61) originated from the United States.Europe contributed 10 studies (13%): Austria and the United Kingdom (n = 2 each), Portugal, Hungary, Cyprus, Greece, the Netherlands and Germany (n = 1 each).The remaining 4 studies (5%) were from the Asia-Pacific region (Japan n = 2, New Zealand n = 2).Throughout the years, academic outcomes remained the primary focus.Physical health outcomes began gaining traction in the year 2006, and health behaviours started becoming prominent around the year 2013.
10 studies (13%): Austria and the United Kingdom (n = 2 each), Portugal, Hungary, Cyprus, Greece, the Netherlands and Germany (n = 1 each).The remaining 4 studies (5%) were from the Asia-Pacific region (Japan n = 2, New Zealand n = 2).Throughout the years, academic outcomes remained the primary focus.Physical health outcomes began gaining traction in the year 2006, and health behaviours started becoming prominent around the year 2013.

Figure 2 .
Figure 2. Temporal trends in research on children's summertime academic outcomes, health, and wellbeing.Number of studies published for each outcome type and geographic location (US-based or outside the US) between 2000 and 2022.

Figure 2 .
Figure 2. Temporal trends in research on children's summertime academic outcomes, health, and wellbeing.Number of studies published for each outcome type and geographic location (US-based or outside the US) between 2000 and 2022.

Figure 4 .
Figure 4. Physical health changes over the summer.Physical health changes using measures of adiposity and fitness.Statistically significant changes are shaded in a dark colour.Suggestive changes (not testing/reaching significance) are shaded in a light colour.Non-significant or significant and conflicting changes are shaded grey.

Figure 4 .
Figure 4. Physical health changes over the summer.Physical health changes using measures of adiposity and fitness.Statistically significant changes are shaded in a dark colour.Suggestive changes (not testing/reaching significance) are shaded in a light colour.Non-significant or significant and conflicting changes are shaded grey.

Figure 5 .
Figure 5. Physical activity changes over the summer.Changes in MVPA, LPA and SB across summer.Statistically significant changes are shaded in a dark colour.Suggestive changes testing/reaching significance) are shaded in a light colour.Non-significant or significant and flicting changes are shaded grey.

Figure 6 .
Figure 6.Changes in other health behaviours over the summer.Changes in sleep, diet and sc time behaviours across summer.Statistically significant changes are shaded in a dark colour.S gestive changes (not testing/reaching significance) are shaded in a light colour.Non-significan significant and conflicting changes are shaded grey.

Figure 5 . 35 Figure 5 .
Figure 5. Physical activity changes over the summer.Changes in MVPA, LPA and SB across the summer.Statistically significant changes are shaded in a dark colour.Suggestive changes (not testing/reaching significance) are shaded in a light colour.Non-significant or significant and conflicting changes are shaded grey.

Figure 6 .
Figure 6.Changes in other health behaviours over the summer.Changes in sleep, diet and screen time behaviours across summer.Statistically significant changes are shaded in a dark colour.Suggestive changes (not testing/reaching significance) are shaded in a light colour.Non-significant or significant and conflicting changes are shaded grey.

Figure 6 .
Figure 6.Changes in other health behaviours over the summer.Changes in sleep, diet and screen time behaviours across summer.Statistically significant changes are shaded in a dark colour.Suggestive changes (not testing/reaching significance) are shaded in a light colour.Non-significant or significant and conflicting changes are shaded grey.

Figure 7 .
Figure 7. Academic outcomes of disadvantaged children over the summer.Academic outco disadvantaged children (left) and academic outcomes for disadvantaged children compa (right).Statistically significant changes are shaded in a dark colour.Suggestive chang

Figure 7 .
Figure 7. Academic outcomes of disadvantaged children over the summer.Academic outcomes for disadvantaged children (left) and academic outcomes for disadvantaged children comparatively (right).Statistically significant changes are shaded in a dark colour.Suggestive changes (not testing/reaching significance) are shaded in a light colour.Non-significant or significant and conflicting changes are shaded grey.

Table 1 .
Study characteristics table.Characteristics of included studies.Legend: Time points of summer measures: Pre/post single summer: Changes measured over a single summer period, with data collected at two time points, one at the start and one at the end of summer.Pre/post multiple summers: Study measured changes over more than one summer, with pre-summer and post-summer measures.School comparison: Study compared the outcome between the summer holidays and school period.1× summer + 1× school: Rather than changes across the summer, the study contrasted an outcome at one school period time point and one summer period time point.Outcomes: Summarizes the outcomes of interest and the type of tool used.Disadvantage: The study considered the impact of disadvantage on the outcomes of interest.
Control group data from primarily "at-risk, struggling readers" in schools identified as serving low-income families.Age: Kindergarten to grade 2. Control group data: N = 151 (% F not reported).
African American and Hispanic Teens at a mid-sized urban middle school.Age: 6th and 7th grade.N = 192 (% F not reported).Y
N Abbreviations: ✓ denotes study design includes these features.BIA: bioelectric impedance analysis, BSS: Baltimore-based Beginning School Study, CAT: California Achievement Test.CDC: Centers for Disease Control, CVF: Cardiovascular fitness, DIBELS: Dynamic Indicators of Basic Early Literacy Skills Oral Reading Fluency, ECLS: Early Childhood Longitudinal Study, GRADE: Group Reading Assessment and Diagnostic Evaluation test, ISD: Independent school district, ITBS: Iowa Tests of Basic Skills, K: Kindergarten, MAP: Measures of academic progress, METs: Metabolic equivalent of task, MVPA: Moderate-vigorous physical activity, NAEPF: National Assessment of Educational Progress Framework, NWEA: Northwest Evaluation Association data set, OB: Obese, OW: Overweight, PA: Physical activity, PACER: 20-metre progressive aerobic cardiovascular endurance run, SB: Sedentary behaviour, Yrs: years.