reviews Archives - My Teacher Helper

Online Sportsbook Reviews for US

U.S. Legal Sports Betting History

While much of the focus in the U.S. has been on the growth of sports betting in the years following the repeal of the Professional and Amateur Sports Protection Act in 2018, the country’s betting history goes back much farther than that.

Here’s a look at the biggest moments and milestones in U.S. sports betting history:

19th Century: Sports Betting Begins

The earliest instances of sports betting in America centered exclusively around horse racing events – but that changed in the latter stages of the 19th Century with the introduction of professional baseball. The National League was founded in 1876, and sports betting soon followed; between the Louisville Grays throwing games and legendary manager Cap Anson famously placing wagers on his own team, betting controversies soon made as much history as the actual sport.

Early 20th Century: Black Sox Scandal

You don’t need to be a betting regular to acknowledge that the actions of the 1919 Chicago White Sox cast a pall not only across professional baseball, but of sports wagering, as well. Eight members of that White Sox team accepted bribes from a gambling group (allegedly led by New York City crime boss Arnold Rothstein) to throw the 1919 World Series against the Cincinnati Reds; all eight, including star outfielder “Shoeless” Joe Jackson, were given lifetime bans in 1921 but avoided any criminal charges.

1940s: Legal Sports Betting is Born

A decade after Nevada Governor Fred Balzar signed Bill AB 98 into law – allowing for legal gambling within the state’s borders – noted mobster Bugsy Siegel made history in 1941 as the first race disseminator in the state. Siegel’s race wire service provided centralized odds and results for bookies. The end of the decade saw Nevada officially legalize sports wagering, though betting was limited to turf clubs, which operated independently of the casinos.

1950s: Excise Tax Sends Sportsbooks Running

Just as the popularity of Las Vegas sportsbooks was climbing, the federal government stepped in and turned the industry on its ear. A whopping 10 percent excise tax on sports betting handle – part of the Revenue Act of 1951 – effectively shuttled many legal sports betting operators, while others sought out less-than-legal ways around the tax.

Regulation was the focus of the latter part of the decade. The state legislature created the Gaming Control Board in 1955 to help regulate the ever-growing Nevada gaming industry, while the Gaming Control Act was passed four years later, putting the Nevada Gaming Commission in charge of all gaming licensing. And with the mob engaging in heavy illegal sports betting activity elsewhere in the country, more stringent regulations were on the way.

1960s: Feds Crack Down on Mob Betting Activity

The U.S. government came down hard on illegal sports betting operations in 1961, implementing the Interstate Wire Act (also known as the Federal Wire Act). The act, which remains in effect today, prohibits sports wagering from crossing state lines:

Whoever being engaged in the business of betting or wagering knowingly uses a wire communication facility for the transmission in interstate or foreign commerce of bets or wagers or information assisting in the placing of bets or wagers on any sporting event or contest, or for the transmission of a wire communication which entitles the recipient to receive money or credit as a result of bets or wagers, or for information assisting in the placing of bets or wagers, shall be fined under this title or imprisoned not more than two years, or both.

Elsewhere, the beginning of the decade saw Nevada crack the $200 million mark in annual gross gaming revenue – and it also marked the beginning of an incredible casino expansion.

Caesars Palace’s opening in 1966 was the most notable addition to the Las Vegas casino scene, punctuating a stretch in which Harvey’s, the original Aladdin, Circus Circus, Landmark, International and Monte Carlo all made their debuts.

1970s: Welcome Tax Relief for Sportsbooks

As more casinos popped up along the suddenly-expanding Las Vegas Strip in the 1970s, Congress finally made things right after nearly a quarter-century of exorbitant sports betting handle tax.

After much urging from Senator Howard Cannon, Congress finally decided in 1974 to lower the excise tax from 10 percent all the way down to two percent. One year later, following the state passing a law allowing casinos to host sportsbooks, Union Plaza Hotel and Casino owner Jimmy Gaughan made history as the first man to do so.

Elsewhere, Nevada briefly had company in the sports betting sphere. Delaware introduced its sports lottery in 1976, then promptely shuttered it just three weeks later (and voiding all active tickets in the process) after incurring more than $376,000 in debt.

1980s: Vegas Sportsbooks Rejoice

The 1980s brought more good news for Nevada, as Congress lowered the tax rate on licensed books to 0.25 percent. This, combined with a 6.75 percent state tax on gross gaming revenue and one percent licensing fees, put operators in position to compete with – and ultimately outdo – illegal sportsbooks.

Meanwhile, two other states tried their hand at a less polished form of sports betting. The Montana Lottery was created in 1986 and offered limited sports pools and fantasy sports wagering, while Oregon’s Sports Action parlay offering was introduced three years later. These new ventures raised concerns in Congress, setting the stage for a bombshell that would stun the sports betting world.

1992: PASPA Limits the Playing Field

In response to a growing number of states interested in implementing some form of sports betting, Congress enacted the Professional and Amateur Sports Protection Act (PASPA), which banned sports wagering in all states except for the four (Nevada, Oregon, Montana, Delaware) which had already put sports betting options in place.

All states that had operated licensed casino games for the 10-year period prior to PASPA’s enactment were eligible to add sports betting to their gaming offering, but were given just 12 months in which to do so. New Jersey was the one state expected to take advantage of this window, but failed to do so.

2000s: Nevada Rebounds From 9-11

Nevada’s continued growth explosion finally came to a sobering halt after the terror attacks of September 11, 2001. Tourist activity dried up significantly, resulting in mass layoffs and shutdowns; it would take until 2005 for things to return to normal.

Even with a massive slowdown earlier in the decade, Las Vegas returned as one of the world’s most popular tourist destinations when people did start to feel safe traveling again. Revenue passed the $10 billion mark annually in 2004, and more casino-hotel combos popped up, including Wynn Las Vegas, Encore Las Vegas and The Palazzo.

Across the rest of the U.S., sports bettors who had discovered

2011-13: NJ legislation passes; leagues fight back

A New Jersey sports-betting referendum held back in November 2011 was overwhelmingly approved, leading to the Sports Wagering Act of 2012 that allowed for “wagering at casinos and racetracks on certain professional and collegiate sports or betting events.”

Alas, it wasn’t that simple. The five biggest sports organizations in North America (NFL, MLB, NHL, NCAA) blocked legislation, successfully arguing that New Jersey’s bill violated PASPA. New Jersey followed up with an appeal, but it was also unsuccessful.

Meanwhile, the early-2010s proved to be the most challenging period for Las Vegas in decades. Early during that period, a deep recession significantly curtailed tourism and spending, resulting in widespread layoffs and major delays to casino construction, expansion or refurbishment projects.

2014-17: NJ Wins Audience With SCOTUS

New Jersey Governor Chris Christie, who had unsuccessfully tried to push through the first sports betting bill, had another trick up his sleeve. In October 2014, he signed off on legislation that would allow casinos and racetracks to offer sports betting by repealing state law that bans the practice.

The leagues wasted no time responding – and this time, the NBA was involved as well. The organizations suggested that Christie was simply trying to find another way around PASPA – and after an injunction was granted, the U.S. Third District Court of Appeals upheld the decision 2-1 in the summer of 2015.

Frustrated but undaunted, New Jersey lawmakers sought to take their case to the highest court in the United States. But even before they got the opportunity, the Supreme Court asked US Solicitor General Jeffrey Wall to weigh in – and he recommended in May 2017 that SCOTUS not even bother with a hearing.

Just over a month later, SCOTUS stunned just about everyone by agreeing to grant New Jersey’s petition for a hearing. And while the path to this moment had been largely a solo journey for the Garden State, a whopping 20 states filed amicus briefs with the court (along with the highly-respected American Gaming Association) in support of New Jersey’s quest to legalize sports betting.

2018: PASPA Vanishes, Sports Betting Launches

After a wait of five-plus months, the Supreme Court finally ruled – and by a 6-3 count, SCOTUS declared that the federal ban on sports wagering is unconstitutional. That set in motion a frenzy of activity across the country – most significantly in New Jersey, which was expected to become Ground Zero for the new era of U.S. sports betting.

The following month, Governor Phil Murphy signed Assembly Bill 4111, allowing for the introduction of legal sports betting at casinos and racetracks. Less than two months after that, DraftKings Sportsbook became the first online sportsbook operator to go live in New Jersey – and the first to operate anywhere outside Nevada.

NJ wasn’t the only state to jump on board the sports betting train in Year 1 post-PASPA. Delaware was actually the first state outside NV to provide legal sports betting (via a retail location), while New Mexico, Mississippi, Pennsylvania, Rhode Island and West Virginia also took their first wagers in 2018.

2019: NJ Dominates Sports Betting Landscape

Having done much of the legwork ahead of time, New Jersey was miles ahead of the rest of the country at rolling out legal sports betting – and it showed. Serving as a test case for the other states, New Jersey saw immediate success, putting together five straight months of $300+ million in handle to open 2019.

From there, the NFL and NCAA football seasons took center stage – and New Jersey saw truly eye-popping numbers in terms of handle, bringing in nearly $2.6 billion from September 2019 to January 2020 while finishing the calendar year at $4.6 billion.

The industry also saw a significant number of new states enter the fray. Arkansas, Indiana, Iowa, New Hampshire and Oregon all took their first legal sports wagers in 2019.

2020: COVID-19 Halts Momentum

Just as an ever-increasing number of legislated states set their collective sights on another set of monthly records, the COVID-19 pandemic sent the entire North American sports calendar into flux. Sportsbooks, casinos and tax collectors all took a major hit over the four-month period from March to June (though the state still pulls in $520 million in handle over that span).

As sports gradually returned over the summer and both the NFL and NCAA football rolled out full schedules (or close to them), bettors came back in droves. New Jersey set monthly handle records in three straight months before ending 2020 in style with a $996-million showing in December (the topper to a $6-billion year). Several other states smashed their monthly handle marks, as well.

COVID-19 also did little to slow down the implementation of sports betting legislation in a handful of other states. Colorado, Illinois, Michigan, Montana, Tennessee, Washington and DC all entered the market in 2020, though many of those states saw modest early handles due to the coronavirus.

2021: Records Fall Everywhere

The U.S. sports betting phenomenon reached a whole new level in 2021 – and as usual, New Jersey was at the epicenter. On the heels of a $959-million handle for January, the state regularly shattered monthly records post-NFL – then saved its best for the 2021 season, posting the first billion-dollar handles in each of the final four months of the season. The final tally: $10.93 billion in handle.

This trend hardly belonged to New Jersey, with every state operating legal sports betting having enjoyed record numbers in 2021. And as expected, even more states became part of the U.S. betting landscape, with Arizona, Connecticut, Nebraska, North Carolina, South Dakota, Virginia, Wisconsin and Wyoming accepting legal wagers for the first time.

2022: No Stopping New York

Despite massive growth in the U.S. sports betting industry, none of the Big Four states offered legal sports wagering going into 2022. That all changed in the second week of January, when New York (No. 4 in the country in terms of population) joined the club – and promptly raked in the dollars.

Empire State sportsbooks brought in an unbelievable $1.69 billion for the month despite not launching until Jan. 8 – and that momentum carried through the first half of the year, with New York bringing in more than $10.6 billion in handle through its first eight months of operation.

It was otherwise a much slower year in terms of new state legislation, with only Louisiana joining NY as of October 2022.

Sports Betting Regulatory Bodies

While repealing PASPA was the decision of the U.S. Supreme Court, each state is responsible for determining its own set of sports betting regulations and restrictions. Here are the main governing bodies for the most notable states with legal sports wagering in place:

New York State Gaming Commission

New Jersey Division of Gaming Enforcement

Nevada Gaming Control Board

Pennsylvania Gaming Control Board

Illinois Gaming Board

Effectiveness of physical activity interventions for improving depression, anxiety and distress: an overview of systematic reviews

Introduction

Mental health disorders are among the leading causes of the global health-related burden, with substantial individual and societal costs.1 2 In 2019, one in eight people (970 million) worldwide were affected by a mental health disorder3 and almost one in two (44{af0afab2a7197b4b77fcd3bf971aba285b2cb7aa14e17a071e3a1bf5ccadd6db}) will experience a mental health disorder in their lifetime.4 The annual global costs of mental health disorders have been estimated at $2.5 trillion (USD), which is projected to increase to $6 trillion (USD) by 2030.5 Depression is the leading cause of mental health-related disease burden,6 while anxiety is the most prevalent mental health disorder.3 Additionally, the COVID-19 pandemic has been associated with increased rates of psychological distress, with prevalence ranging between 35{af0afab2a7197b4b77fcd3bf971aba285b2cb7aa14e17a071e3a1bf5ccadd6db} and 38{af0afab2a7197b4b77fcd3bf971aba285b2cb7aa14e17a071e3a1bf5ccadd6db} worldwide.7–9

The role of lifestyle management approaches, such as exercise, sleep hygiene and a healthy diet, varies between clinical practice guidelines in different countries. In US clinical guidelines,10 psychotherapy or pharmacotherapy is recommended as the initial treatment approaches, with lifestyle approaches considered as ‘complementary alternative treatments’ where psychotherapy and pharmacotherapy are ‘ineffective or unacceptable’. In other countries such as Australia, lifestyle management is recommended as the first-line treatment approach,11 12 though in practice, pharmacotherapy is often provided first.

There have been hundreds of research trials examining the effects of physical activity (PA) on depression, anxiety and psychological distress, many of which suggest that PA may have similar effects to psychotherapy and pharmacotherapy (and with numerous advantages over psychotherapy and pharmacotherapy, in terms of cost, side-effects and ancillary health benefits).13–18 Despite the evidence for the benefits of PA, it has not been widely adopted therapeutically. Patient resistance, the difficulty of prescribing and monitoring PA in clinical settings, as well as the huge volume of largely incommensurable studies, have probably impeded a wider take-up in practice.13 14 17

Meta-reviews are systematic reviews of systematic reviews, offering a way of synthesising a vast evidence base. While there have been several meta-reviews of PA for depression, anxiety and psychological distress,17 19–24 they have focused on specific population subgroups, particular conditions (eg, depression only) or on particular forms of PA. We set out to undertake the most comprehensive synthesis to date of evidence regarding the effects of all modes of PA on symptoms of depression, anxiety and psychological distress in adult populations.

Methods

Protocol and registration

The protocol for this systematic umbrella review was prospectively registered on PROSPERO and results are reported according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)25 guidelines.

Selection criteria and search strategy

The population, intervention, comparison, outcomes and study type (PICOS) framework was used to develop the inclusion criteria as follows: population: any adult population (aged ≥18 years); intervention: interventions designed to increase PA. The following definition of PA was used: ‘any bodily movement produced by the contraction of skeletal muscles that results in a substantial increase in caloric requirements over resting energy expenditure’.26 Reviews were eligible irrespective of PA modality, supervision, delivery (eg, in-person or online) or dose (frequency, intensity and duration). Reviews were ineligible if they included any randomised control trials (RCTs) of non-PA interventions, if PA was combined with another intervention (eg, diet) or if they evaluated single bouts of acute exercise. Comparator: reviews were eligible if ≥75{af0afab2a7197b4b77fcd3bf971aba285b2cb7aa14e17a071e3a1bf5ccadd6db} of the included RCTs involved either usual care, waitlist, nothing an equal attention intervention or a lower/lesser PA intervention (eg, a supervised exercise intervention vs printed PA materials). During study selection, it became apparent that the comparator inclusion/exclusion criteria needed elaboration. After careful consideration and discussion, we decided to exclude reviews where >25{af0afab2a7197b4b77fcd3bf971aba285b2cb7aa14e17a071e3a1bf5ccadd6db} of component RCTs compared PA to pharmaceutical interventions or compared two types of equal dose exercise (eg, resistance vs aerobic exercise) without a non-PA comparison, since the inclusion of such reviews would limit our ability to evaluate the effectiveness of PA per se. Outcomes: any self-report or clinician-rated assessment of depression, anxiety or psychological distress symptoms. Study type: systematic reviews with meta-analyses of RCTs only, which included meta-analyses of the outcomes of interest.

Twelve databases were searched (CINAHL, Cochrane, Embase, MEDLINE, Emcare, ProQuest Health and Medical Complete, ProQuest Nursing and Allied Health Source, PsycINFO, Scopus, Sport Discus, EBSCOhost and Web of Science) using subject heading, keyword and Medical Subject Headings (MeSH) term searches for ‘systematic review’, ‘meta-analysis’, ‘physical activity’, ‘exercise’, ‘anxiety’, ‘depression’ and ‘psychological distress’ (see online supplemental eTable 1 for the full search strategy). Database searches were limited to peer-reviewed journal articles published in English language from inception to 1 January 2022.

Data management and extraction

Search results were imported into EndNote V.x9 (Clarivate, Philadelphia) where duplicates were removed, then exported into Covidence (Veritas Health Innovation, Melbourne, Australia). Title/abstract and full-text screening, data extraction and risk of bias scoring were completed in duplicate by two independent reviewers (BS and AM, AW, CEMS, DD, EE, EO, KS, RC, RV or TF), with disagreements resolved by team discussion.

Data were extracted in duplicate by two independent reviewers (BS and AM, AW, CEMS, DD, EE, EO, KS, RC, RV or TF) using a standardised extraction form,27 28 and discrepancies were resolved by team discussion. The risk of bias of the included reviews was assessed by two independent reviewers (BS and AM, AW, CEMS, DD, EE, EO, KS, RC, RV or TF) in duplicate using the A MeaSurement Tool to Assess systematic Reviews (AMSTAR-2) tool.29 The AMSTAR-2 tool involves 16 items, with each item scored as yes, partial yes or no. Seven items are considered ‘critical’ and nine ‘non-critical’.29 The critical domains are protocol registration, adequacy of search strategy, justification for excluding individual studies, risk of bias assessment, appropriateness of meta-analysis methods, use of risk of bias during interpretation and assessment of publication bias. Reviews were rated as ‘high confidence’ (0 critical weakness and <3 non-critical weaknesses), ‘moderate’ (one critical weakness and <3 non-critical weaknesses), ‘low’ (>1 critical weakness and <3 non-critical weaknesses) or ‘critically low’ (>1 critical weakness and ≥3 non-critical weaknesses).29

Umbrella review synthesis methods

The overlap in component RCTs that were included across all eligible reviews was assessed using the Corrected Covered Area (CCA) method.30 A CCA of 100{af0afab2a7197b4b77fcd3bf971aba285b2cb7aa14e17a071e3a1bf5ccadd6db} indicates that every review included in our umbrella review comprised the same component RCTs, while a CCA of 0{af0afab2a7197b4b77fcd3bf971aba285b2cb7aa14e17a071e3a1bf5ccadd6db} indicates that every review in our umbrella review included entirely unique RCTs. The following cut-offs were used to quantify the CCA: 0{af0afab2a7197b4b77fcd3bf971aba285b2cb7aa14e17a071e3a1bf5ccadd6db}–5{af0afab2a7197b4b77fcd3bf971aba285b2cb7aa14e17a071e3a1bf5ccadd6db}=‘slight overlap’; 6{af0afab2a7197b4b77fcd3bf971aba285b2cb7aa14e17a071e3a1bf5ccadd6db}–10{af0afab2a7197b4b77fcd3bf971aba285b2cb7aa14e17a071e3a1bf5ccadd6db}=‘moderate’; 11{af0afab2a7197b4b77fcd3bf971aba285b2cb7aa14e17a071e3a1bf5ccadd6db}–15{af0afab2a7197b4b77fcd3bf971aba285b2cb7aa14e17a071e3a1bf5ccadd6db}=‘high’ and >15{af0afab2a7197b4b77fcd3bf971aba285b2cb7aa14e17a071e3a1bf5ccadd6db}=‘very high’ overlap.30 Publication bias was assessed by creating a funnel plot and observing the presence of asymmetries or missing sections.31

Meta-analysis results from each review were presented using forest plots. Separate forest plots were created for meta-analyses reporting standardised (eg, standardised mean difference, SMD) and unstandardised effect sizes (eg, mean difference). For meta-analyses that reported standardised effect sizes, we undertook subgroup analyses for clinical status and intervention characteristics. Meta-analysis results were summarised using medians and IQRs

The Oxford Centre for Evidence-Based Medicine levels of evidence and grades for recommendations32 were used to classify the overall level of evidence as grade A: consistent level 1 studies (ie, systematic reviews of RCTs or individual RCTs); B: consistent level 2 (ie, systematic reviews of cohort studies or individual cohort studies) or level 3 studies (ie, systematic reviews of case–control studies or individual case–control studies) or extrapolations from level 1 studies; C: level 4 studies (ie, case series) or extrapolations from level 2 or 3 studies or D: level 5 (ie, expert opinion without explicit critical appraisal) evidence or troublingly inconsistent or inconclusive studies of any level.32

Results

Of the 1280 records identified, 97 were eligible. They included 1039 unique (component) RCTs and the CCA was 0.6{af0afab2a7197b4b77fcd3bf971aba285b2cb7aa14e17a071e3a1bf5ccadd6db}, indicating slight overlap (see online supplemental eFigure 1 for PRISMA flowchart, including reasons for exclusions). Evaluation of funnel plots indicated no evidence of publication bias (online supplemental eFigure 2).

An overview of all reviews’ characteristics is shown in online supplemental eTable 2. There was a total of >128 119 participants (n=133 did not report the number of participants). Mean participant age ranged from 29 to 86 (median=55) years, and most reviews (n=83, 86{af0afab2a7197b4b77fcd3bf971aba285b2cb7aa14e17a071e3a1bf5ccadd6db}) involved female and male participants. An overview of all populations and PA modalities is shown in table 1. Fifteen reviews specifically involved individuals with depression33–41 and three involved individuals with anxiety.42–44 Most reviews involved various PA modes (n=70) and most (n=77) had a critically low AMSTAR-2 score (low: n=10; high: n=10, online supplemental eTable 3).

Table 1

Overview of all populations, conditions and physical activity modes of the included reviews

Meta-analysis results: depression

Results from 72 meta-analyses based on SMD (n=875 component RCTs, >62 040 participants) showed a medium effect in favour of PA for reducing depression and depressive symptoms (median SMD=−0.43, IQR=−0.66 to –0.27, figure 1).

Figure 1

Results of meta-analyses that assessed symptoms of depression using standardised mean differences (negative values represent a reduction in symptoms).

MD effect size for each instrument was: profile of mood states: −7.68 (1 review), Beck Depression Inventory: −5.53 (IQR=−6.24 to –4.81), The Edinburgh Postnatal Depression Scale: −2.97 (IQR=−3.49 to –2.44), self-rating scale: −3.99 (one review), Brief Symptom Inventory 18: −3.02 (one review), Centre for Epidemiological Studies Depression: −0.36 (IQR=−1.25 to 0.02), Montgomery-Asberg Depression Rating Scale: −1.80 and Hospital Anxiety and Depression Scale: −1.26 (IQR=−1.41 to –1.18, online supplemental eFigure 3 and online supplemental eTable 4).

Grade of recommendation: (A) Consistent level 1 studies.

Anxiety

Results from 28 meta-analyses using SMD (171 component RCTs, >10 952 participants) showed a medium effect of PA for reducing anxiety (median SMD=−0.42, IQR=−0.66 to –0.26, figure 2).

Figure 2

Results of meta-analyses that assessed symptoms of anxiety using standardised mean differences (negative values represent a reduction in symptoms).

MD effect sizes for each instrument were: The State-Trait Anxiety Inventory: −3.61 (IQR=−6.01 to –1.66), Brief Symptom Inventory-18: −5.45 (1 review), Self-rating scale: −4.57 (1 review), Hospital Anxiety and Depression Scale: −1.26 (IQR=−1.26 to –0.79, online supplemental eTable 4 and online supplemental eFigure 5).

Grade of recommendation: (A) Consistent level 1 studies.

Psychological distress

One systematic review45 reported SMD results for psychological distress (six component RCTs, 508 participants), while another systematic review46 reported MD results (one component RCT, 39 participants). Results showed a medium effect in favour of PA, compared with usual care (SMD=−0.60, 95{af0afab2a7197b4b77fcd3bf971aba285b2cb7aa14e17a071e3a1bf5ccadd6db} CI −0.78 to –0.42). For MD, findings showed no significant effect (MD=−0.30, 95{af0afab2a7197b4b77fcd3bf971aba285b2cb7aa14e17a071e3a1bf5ccadd6db} CI −5.55, 4.95, one review, one component RCT, 39 participants).

Grade of recommendation: (B) Consistent level 2 or 3 studies or extrapolations from level 1 studies.

Subgroup analyses: clinical status

Depression

Seventeen reviews provided data on patients with cancer,45 47–62 and 16 on people with depression or depressive symptoms.10 33 39 63–75 PA was effective in reducing depressive symptoms across all conditions (median SMD range: –0.85 (kidney disease), –0.16 (cardiovascular disease)). The largest effects were found in kidney disease, HIV, chronic obstructive pulmonary disease, generally healthy adults and individuals diagnosed with depression (table 2).

Table 2

Summary data on the effects of physical activity interventions on depression for a range of clinical conditions, including the number of reviews, studies and participants covered; and the 25th percentile, median and 75th percentile for standardised mean differences

Depression

Three reviews42 50 78 presented analyses on session duration (online supplemental content 17). Long (≥60 min, SMD=–0.57, IQR –0.85 to –0.35) and medium (30–60 min, SMD=–0.60, IQR –0.78 to –0.41) session durations had similar benefits. The sole study of short sessions (<30 min) had a SMD of 0.01 (online supplemental eFigure 15).

Discussion

This is the first ever study to compile the extensive base of evidence regarding the effects of PA on depression, anxiety and psychological distress. We identified 97 systematic reviews, reporting the findings of 1039 unique RCTs, involving 128 119 participants. Findings suggest that PA interventions are effective in improving symptoms of depression and anxiety. Improvements were observed across all clinical populations, though the magnitude of effect varied across different clinical populations. The greatest benefits were seen in people with depression, pregnant and postpartum women, apparently healthy individuals and individuals diagnosed with HIV or kidney disease. All PA modes were effective, and higher intensity exercise was associated with greater improvements for depression and anxiety. Longer duration interventions had smaller effects compared with short and mid-duration, though the longest duration interventions still had positive effects.

PA was effective at reducing depression and anxiety across all clinical conditions, though the magnitude of the benefit varied between clinical groups. The larger effect sizes observed in clinical populations may reflect that these populations experience above-average symptoms of depression and anxiety and have low PA levels, and, therefore, have a greater scope for improvement compared with non-clinical populations.17

All PA modes were beneficial, including aerobic, resistance, mixed-mode exercise and yoga. It is likely that the beneficial effects of PA on depression and anxiety are due to a combination of various psychological, neurophysiological and social mechanisms.87 Different modes of PA stimulate different physiological88 and psychosocial effects,88–90 and this was supported by our findings (eg, resistance exercise had the largest effects on depression, while Yoga and other mind–body exercises were most effective for reducing anxiety). Furthermore, our findings showed that moderate-intensity and high-intensity PA modes were more effective than lower intensities. PA improves depression though various neuromolecular mechanisms including increased expression of neurotrophic factors, increased availability of serotonin and norepinephrine, regulation of hypothalamic–pituitary–adrenal axis activity and reduced systemic inflammation.91 92 Therefore, low-intensity PA may be insufficient for stimulating the neurological and hormonal changes that are associated with larger improvements in depression and anxiety.87 Overall, our findings add further support to public health guidelines, which recommend multimodal, moderate and vigorous intensity PA.

Our findings that longer duration interventions were less effective than shorter interventions may seem counter intuitive. It is possible that this finding reflects a decline in adherence with longer interventions. Furthermore, due to a lack of blinding of participants in PA trials, participants may have expected to have improved symptoms. It is possible that after experiencing short-term improvements in depression or anxiety, the expectancy effect may diminish over longer periods of time. An alternative explanation is that the longer interventions might not provide sufficient progression of PA dose, leading to a reduction in their effectiveness. Furthermore, it was somewhat surprising that smaller weekly duration interventions demonstrated larger effects than higher weekly duration. This is the opposite to the dose–benefit relationship observed for exercise and physical health outcomes.93 It is possible that shorter duration interventions are easier for participants to comply with, whereas longer weekly duration interventions are more burdensome and that may be impacting the psychological benefits. It is a useful message that interventions do not need to provide high doses of PA for improvements in depression.

The key strength of this study was that it is the first umbrella review to evaluate the effects of all types of PA on depression, anxiety and psychological distress in all adult populations. We included only the highest level of evidence: meta-analyses of RCTs and applied stringent criteria regarding the design of the component RCTs to ensure that effects could be confidently attributed to PA rather than other intervention components. Additionally, there was only slight overlap in the component RCTs, increasing our confidence in the findings.

A limitation of the review is that most evidence focused on mild-to-moderate depression, with fewer reviews addressing anxiety and psychological distress, preventing us from reaching firm conclusions in the subgroup analyses for these outcomes. Furthermore, most (n=77) of the included reviews were rated as ‘critically low’, based on the AMSTAR-2 quality rating.

Clinical implications

PA is effective for managing symptoms of depression and anxiety across numerous populations, including the general population, people with mental illnesses and various other clinical populations. While the benefit of exercise for depression and anxiety is generally recognised, it is often overlooked in the management of these conditions. Furthermore, many people with depression and anxiety have comorbidities, and PA is beneficial for their mental health and disease management. This underscores the need for PA to be a mainstay approach for managing depression and anxiety.

All modes of PA are effective, with moderate-to-high intensities more effective than low intensity. Larger benefits are achieved from shorter interventions, which has health service delivery cost implications–suggesting that benefits can be obtained following short-term interventions, and intensive long-term interventions are not necessarily required to achieve therapeutic benefit. The effect size reductions in symptoms of depression (−0.43) and anxiety (−0.42) are comparable to or slightly greater than the effects observed for psychotherapy and pharmacotherapy (SMD range=−0.22 to −0.37).94–97 Future research to understand the relative effectiveness of PA compared with (and in combination with) other treatments is needed to confirm these findings.

In conclusion, PA is effective for improving depression and anxiety across a very wide range of populations. All PA modes are effective, and higher intensity is associated with greater benefit. The findings from this umbrella review underscore the need for PA, including structured exercise interventions, as a mainstay approach for managing depression and anxiety.

What is already known

Previous research trials suggest that physical activity may have similar effects to psychotherapy and pharmacotherapy for patients with depression, anxiety or psychological distress.
Studies have evaluated different forms of physical activity, in varying dosages, in different population subgroups, and using different comparator groups, making it difficult for clinicians to understand the body of evidence for physical activity in the management of mental health disorders.

What are the new findings

Results showed that physical activity is effective for reducing mild-to-moderate symptoms of depression, anxiety and psychological distress (median effect size range=−0.42 to –0.60), compared with usual care across all populations.
Our findings underscore the important role of physical activity in the management of mild-to-moderate symptoms of depression, anxiety and psychological distress.