Reducing Rates of Exercise- and Sports-Related Cardiac Mortality

He who saves a single life saves the whole world.

Talmud Sanhedrin 4:5¹

Substantial evidence indicates that routine, systematic engagement in physical activity and exercise training—particularly activities that improve cardiorespiratory fitness— can prevent a range of diseases, including cardiovascular disease (CVD) and certain types of cancer, and reduce the risk of death from non-CVD and non-cancer causes.2, 3, 4, 5, 6 Despite the cardioprotective benefits of regular physical activity and exercise training, vigorous activities may acutely and transiently increase the risk of adverse CVD events in certain susceptible individuals, such as those with structural cardiac diseases. Despite this risk–benefit tradeoff, sudden cardiac arrest (SCA) and sudden cardiac death (SCD) remain a prominent public health concern worldwide. Although rare, the sudden loss of a presumably healthy, active, young individual, is a tragic event with far-reaching implications for families and entire communities.7, 8, 9, 10 Although the epidemiology and public health burden of SCA and/or SCD in young competitive athletes has been well documented, the incidence and clinical characteristics of such events outside of formal sports-specific settings are less well known.

In this issue, Richard and colleagues¹¹ drew upon a comprehensive registry of 2234 deaths associated with sports and recreation in Quebec, Canada from 2006-2019, focusing specifically on the 297 deaths (13.3% of total deaths) found to be from “natural” causes. The highest frequencies of deaths among individuals occurred in cycling (n = 61; 20.5%), ice hockey (n = 26; 8.8%), and hunting (n = 24; 8.1%). Additionally, 283 deaths (95.3% of the total) were determined to be of cardiac origin, as ascertained via analysis of autopy and coroner's reports by multiple investigators. Nearby automated external defibrillators (AEDs) were unavailable at nearly two thirds of death sites, whereas bystander cardiopulmonary resuscitation (CPR) was performed in 60.9% of all cases. Deaths in men (n = 275; 92.6%) far exceeded those in women, with mortality rates increasing substantially beginning at 35 years of age and peaking between 45-74 years of age. The authors concluded that early screening for CVDs and more widespread availability of AEDs could help reduce the incidence of these catastrophic events.

A major strength of this analysis was its inclusion of a broad range of SCDs in the general population, encompassing both pediatric and adult cases, as well as incidents occurring in competitive and recreational settings. This approach expands upon the narrower definitions used in previous studies, which primarily focus on young competitive athletes.¹² The population-based death rates from sports- and recreation-related natural deaths (0.26 per 100,000 person-years) and SCDs (0.25 per 100,000 person-years) in Quebec were comparable to those in other parts of the world.¹¹ As found in other studies, male individuals accounted for a large majority (92.6%) of the SCDs related to sports and recreation.¹¹ In studies of young college athletes in the US, most deaths occurred among division-1 collegiate basketball, football, and soccer players, especially those of African-American origin.⁸ In Quebec, among a much different population, the leading causes of death were cycling, ice hockey, and hunting. Also, in very young athletes, the leading causes of death may be cardiomyopathies, especially hypertrophic and congenital cardiac anomalies, but in the “older” population in Quebec (mean age, 53.9 years), the leading causes of death were coronary heart disease (CHD) and premature atherosclerosis. Certainly, widespread prevention strategies, earlier screening, and treatment of CHD risk factors in young adults could potentially reduce the risk of premature CHD deaths. However, the cost-effectiveness and potential negative psychological consequences of primary prevention strategies, such as preparticipation screening, have been debated widely for decades and remain controversial in the field of sports cardiology.^13,14

Additionally, 93.9% of deaths occurred outside of organized competitions or events, whereas only 22.2% took place in sports complexes. As this study included only deaths, this finding paradoxically may reflect improvements in SCA recognition and resuscitation, particularly in public settings where many bystanders are present. For instance, although the total number of SCAs may be higher during organized events and in sports complexes, a greater likelihood of survival in these settings could result in fewer deaths being included in this study; an observation that warrants further investigation. Extreme gender differences in sports- and recreation-related deaths were observed in this study, a finding previously noted by an international systematic review of exercise-related SCA,¹⁵ despite limited explanations for this phenomenon. This observation may be attributed partially to the historically lower proportion of female individuals participating in sports and vigorous exercise.¹⁶ Additionally, the earlier onset and predominance of atherosclerosis and CHD in men¹⁷ may manifest as a survival selection bias in the context of sports- and recreation-related SCD; men may die at a younger age when they are still active, whereas women may die at an older age when they are more sedentary or have aging-related physical activity limitations. Accordingly, data on deaths among women that are related to sports or exercise may be less likely to be collected. Furthermore, the high estrogen levels of premenopausal women confer potent protection against CVD, including SCA and/or SCD that occur during exercise.¹⁸

These findings highlight several issues that should guide the future direction of public health efforts to improve the community response to sports- and recreation-related SCA, thus reducing the proportion of arrests that result in mortality. First, improved AED accessibility likely will have a substantial impact on the overall survival rate, given that most exercise-related SCA incidents—78%—occur with a shockable arrest rhythm, which is much higher than that of non–exercise-related SCAs.^19,20 Crucially, resuscitation training programs for sports- and recreation-related SCA should be tailored to address longstanding gender disparities in CPR provision and AED application, as women receive these interventions at significantly lower rates than men.^19,20 Although placement of AEDs in remote settings (eg, in hunting or ski cabins) or in areas with high levels of exercise traffic, either physically or via drone-delivered AED networks, is an intriguing strategy, maintenance requirements and financial investments may limit the feasibility of this approach. Although still in development and pending regulatory approval in many countries, ultraportable AEDs may offer advantages in the future. However, at present, no convincing evidence supports device performance, clinical outcomes, or safety of these AEDs, highlighting the need for further research on their effectiveness, particularly in sports- and recreation-related settings, before considering widespread adoption.²¹

Designing and trialing a “designated rescuer” model for certain sports could be an interesting avenue for future research and sport policy initiatives. This approach could involve training designated athletes or exercisers in CPR and equipping them with an ultraportable AED to carry on their person during games, competitions, or group exercise sessions. However, this approach is likely only feasible during organized sessions and may be best operationalized in formal team or club environments. Although this model has not been evaluated directly, similar frameworks, such as the mobile AED response teams used in Japanese long-distance road races,^22,23 have yielded high survival rates and favourable neurologic outcomes. Encouraging nearby athletes and exercisers to assist in responding to SCA events may enable prompt resuscitation interventions to occur prior to the arrival of professional responders, optimizing survival outcomes.

Richard and coauthors¹¹ should be applauded for bringing international attention to evidence on sports- and recreation-related CVD mortality in Quebec over a 14-year period, thus raising awareness of the potential ways to reduce the incidence of SCAs and/or SCDs. As emphasized by the quotation at the start of this editorial, reducing premature mortality is a priority for most clinicians, including cardiologists, general internists, and family physicians, and certainly for those involved in the care of athletes and active individuals. The profound psychological consequences and societal losses that result from SCD in these individuals suggest that they should receive our greatest attention and efforts.

Funding Sources

The authors have no funding sources to declare.

Disclosures

The authors have no conflicts of interest to disclose.