Participant safety is of utmost importance to all those who work in health fitness facilities. Musculoskeletal injury is the most common exercise-related complication, and it is important to take steps to prevent and minimize these types of injuries. Although adverse cardiovascular events such as sudden cardiac death (SCD) and acute myocardial infarction (AMI) are much less common than musculoskeletal injury, these may lead to heightened morbidity and mortality and, therefore, warrant specific attention.
Recently, the American College of Sports Medicine (ACSM) published an Expert Consensus Statement (1) that updated and replaced the previous ACSM statement titled “AHA/ACSM Joint Position Statement: Recommendations for Cardiovascular Screening, Staffing, and Emergency Policies at Health/Fitness Facilities,” which was published in June 1998 (2). Selected aspects of the previous statement remain valid, especially the emphasis on the health benefits of exercise and physical activity (PA), the value of a well-trained fitness facility staff, and the necessity of developing and practicing an emergency response plan. However, the updated document presents new approaches to client safety based on the latest scientific advances. Four modulators that directly affect risk management strategies for health fitness facilities have emerged (see Table 1), and these are discussed below. The consensus statement seeks to balance providing a safe exercise environment with the important public health message of promoting PA for all.
TABLE 1 -
Emerging Themes in the 2020 ACSM Expert Consensus Statement to Update Recommendations for Screening, Staffing, and Emergency Policies to Prevent Cardiovascular Events at Health Fitness Facilities
The 1998 AHA/ACSM Joint Position Statement: Recommendations for Cardiovascular Screening, Staffing, and Emergency Policies at Health/Fitness Facilities emphasized “providing recommendations for cardiovascular screening of all persons (children, adolescence and adults) before enrollment or participation in activities at health/fitness facilities.” The current consensus statement seeks to streamline the screening process using ACSM’s exercise preparticipation health screening recommendations (3) and minimize the requirement for medical clearance and other factors that might impede the use of a health fitness facility, based on the following recognition:
• Even low levels of regular PA provide health benefits (4)
• Exercise-related cardiovascular events are rare among healthy adults (5) as well as those with established CVD (6)
• Preexercise screening strategies may be a barrier to PA because they often require individuals to seek medical clearance (7)
• Immediate assistance provided by nonmedical personnel such as dialing 911, initiating bystander cardiopulmonary resuscitation
(CPR), and using an AED can greatly reduce the morbidity and mortality of acute cardiac events |
PA, CARDIORESPIRATORY FITNESS, AND HEALTH
Regular moderate to vigorous physical activity (MVPA) provides significant health benefits, including lower risk of mortality, stroke, type 2 diabetes, osteoporosis, and depression. Habitual MVPA also lowers the risk of cardiovascular disease (CVD) by favorably modifying blood lipid profiles, blood pressure, C-reactive protein, and insulin sensitivity. Cardiorespiratory fitness (CRF) also is a strong prognostic marker for cardiovascular health. Individuals with low levels of CRF have a higher risk of CVD morbidity and mortality, but importantly, the risk decreases with improvements in CRF. Even in individuals with preexisting CVD, increased CRF is associated with a decreased risk of acute cardiovascular events.
;)
The 2nd edition of the U.S. Department of Health and Human Services Physical Activity Guidelines for Americans (8), which is based on the 2018 Physical Activity Guidelines Advisory Committee Scientific Report (9), significantly expanded the list of health benefits attributable to PA (see Table 2) compared with the original 2008 PA guidelines. The report also identified a direct relationship between sedentary behavior and all-cause mortality, incidence of and mortality from CVD, incidence of type 2 diabetes, and incidence of endometrial, colon, and lung cancer. The adverse health outcomes associated with prolonged sitting and sedentary time decrease in magnitude among persons who are more physically active but are not eliminated (10).
TABLE 2 -
Physical Activity and Health Outcomes from the
2018 Physical Activity Guidelines Advisory Committee Scientific Report
The 2018 Physical Activity Guidelines Advisory Committee provided strong evidence for an expanded list of health outcomes associated with greater amounts of PA:
• Reduced risk of excessive weight gain and obesity in adults and children
• Reduced risk of excessive weight gain, gestational diabetes, and postpartum depression in pregnant women
• Reduced risk of dementia
• Reduced incidence of fall-related injuries in older adults
• Lower incidence of endometrial, esophageal, kidney, lung, stomach, and bladder cancers
• Reduced risk of the progression of an existing chronic medical condition in individuals with the most common, noncommunicable
chronic conditions such as osteoarthritis, hypertension, and type 2 diabetes
• Improved sleep quality
• Reduced feelings of depression and anxiety in healthy people and those with existing clinical conditions
• Improved quality of life
• Reduced risk of mortality in individuals with breast, colorectal, or prostate cancer |
Studies have shown that following the national guidelines of 150 minutes/week of moderate-intensity PA or 75 minutes of vigorous PA is associated with reduced rates of CVD and premature mortality. However, significant decreases in CVD and premature mortality have been reported at PA volumes well below these recommended volumes.
Studies have shown that following the national guidelines of 150 minutes/week of moderate-intensity PA or 75 minutes of vigorous PA is associated with reduced rates of CVD and premature mortality. However, significant decreases in CVD and premature mortality have been reported at PA volumes well below these recommended volumes. Therefore, the 2018 guidelines highlight that there are health benefits attributable to any level of PA. For those individuals who perform little to no MVPA, even replacing sedentary behavior with light-intensity PA reduces the risk of all-cause mortality, CVD incidence and mortality, and the incidence of type 2 diabetes (8). The 2018 committee concluded that every minute of MVPA counts toward the overall PA goal and eliminated the minimum requirement of 10-minute bouts. This change provides individuals with varied options on how to achieve their PA goals.
THE CARDIOVASCULAR RISKS OF PA
The incidence of acute cardiovascular events during very light- to moderate-intensity PA is extremely low and similar to that reported under resting conditions. Although participation in regular PA reduces the risk of CVD, there is a transient increase in the risk of SCD and AMI during vigorous-intensity PA (defined as ≥60% heart rate reserve or oxygen uptake reserve or ≥6 metabolic equivalents [METs]). The increased risk of SCD and AMI is disproportionally higher in sedentary individuals with known or occult CVD performing unaccustomed vigorous-intensity exercise (11).
;)
Certain characteristics put individuals at a higher risk for exercise-related cardiovascular events (see Table 3). Males are approximately 10 times more likely than females to experience an acute cardiovascular event during or immediately after vigorous exercise (14). Increasing age is associated with an increased incidence of exertion-related sudden cardiac arrest driven largely by the heightened prevalence of atherosclerotic coronary artery disease (CAD) (15). PA habits also are an important determinant of risk. There is a strong inverse relationship between the risk of exercise-related SCD and hours per week of vigorous PA among apparently healthy men (16). The presence of diabetes and renal disease seems to increase the risk of adverse cardiovascular events during exercise due in part to their pathogenic association with atherosclerotic CAD (17,18). Participation in specific activities has been increasingly associated with exercise-related sudden cardiac arrest, with basketball, soccer, racquet sports, and football linked to the highest risk among young competitive athletes (19) and recreational fitness facility members (6). Environmental stress (including heat/humidity, cold, and altitude) as well as the excitement of competition accentuate the hemodynamic and respiratory responses to exercise and, thereby, increase the risk of exertion-related acute cardiac events (20–22). Structural cardiovascular abnormalities (e.g., Marfan’s syndrome) and some conduction defects (e.g., prolonged QT syndrome) also may increase the likelihood of exercise-related acute cardiac events.
TABLE 3 -
Characteristics Associated with Exercise-Related Cardiac Events
a
Clinical Status
• Multiple previous myocardial infarctions
• Impaired left ventricular function (ejection fraction <35%)
• Rest or unstable angina pectoris
• Serious dysrhythmias at rest
• High-grade left anterior descending coronary artery lesions and/or significant (≥75% occlusion) multivessel atherosclerosis on
angiography
• Low serum potassium
Exercise Training Participation
• Disregard for appropriate warm-up and cool-down
• Consistently exceeds prescribed training heart rate (i.e., intensity violators)
• Infrequent exerciser
Exercise Test Data
• Low and high exercise tolerance (≤4 or ≥10 METs)
• Chronotropic impairment off drugs (<120 BPM)
• Inotropic impairment (exertional hypotension with increasing workloads)
• Myocardial ischemia (angina and/or ST depression ≥0.2 mV)
• Malignant cardiac dysrhythmias (especially in patients with impaired left ventricular function)
Other
• Cigarette smoking
• Male gender
• Obesity
• Hyperlipidemia |
aAdapted from Giri et al. (
12) and Hossack and Hartwig (
13).
The underlying pathology of exercise-related cardiovascular events differs between younger and older adults. Congenital and hereditary abnormalities, including hypertrophic cardiomyopathy and coronary artery abnormalities, are commonly cited causes of exercise-related SCD in young athletes, although recent autopsy studies of high school and college athletes have identified no structural cause in some cases (23). Atherosclerotic CVD is the most common autopsy finding in individuals >40 years old who experience sudden cardiac arrest and SCD during or immediately after strenuous exercise (24).
Although there is an increased relative risk of AMI and SCD during vigorous-intensity exercise, the absolute risk of exercise remains extremely low. Numerous studies that have examined the risk of cardiovascular complications during exercise highlight the rarity of these events and suggest that exercise is safe for most individuals. For example, the Physicians’ Health Study (17) and Nurses’ Health Study (25) reported only 1 SCD per 1.5 million hours of vigorous PA in men and per 36.5 million hours of MVPA in women.
;)
With the growing popularity of high-intensity interval training (HIIT), there is understandable concern about the safety of this exercise approach in selected adults, particularly those with known or occult CAD. HIIT refers to the combination of high-intensity exercise bouts usually lasting 2 to 5 minutes with interspersed periods of more moderate or recovery exercise during the workout. Two recent systematic reviews that examined the cardiovascular complications associated with HIIT conducted in cardiac rehabilitation centers for patients with CAD or heart failure found a low rate of major cardiovascular events. One review, which included 23 studies involving 547 participants completing 17,083 HIIT sessions, reported only one major, nonfatal cardiovascular event (26). The other review of 17 studies reported no deaths or cardiac events requiring hospitalization in 465 patients participating in HIIT (27). Although HIIT provides beneficial health and fitness outcomes and a time-efficient alternative to moderate-intensity continuous exercise, additional long-term studies assessing the safety of HIIT are needed before it can be widely adopted in individuals with known or suspected CVD, especially in unsupervised, nonmedical settings (28).
CARDIOVASCULAR SCREENING OF PROSPECTIVE MEMBERS/USERS
Health and fitness facilities attract people representing the entire spectrum of health ranging from individuals who are apparently healthy to those with established and occult CVD. Therefore, exercise preparticipation health screening (PPHS) may be helpful to maximize safety in these environments. PPHS has been proposed as a tool capable of identifying people at high risk for adverse cardiovascular events during exercise so that they can be referred for medical clearance, providing an opportunity for disease diagnosis and management.
All health and fitness facilities should conduct cardiovascular screening of all new members and prospective users. ACSM has published recommendations for PPHS among adults (3) to help exercise professionals identify new members or users of a health or fitness facility that should be directed for formal medical evaluation before the initiation of exercise. The ACSM PPHS procedure includes the following: 1) a determination of current exercise habits; 2) the identification of established cardiovascular, metabolic, and renal diseases; and 3) the delineation of signs and/or symptoms at rest or during physical exertion, suggesting underlying CVD. This approach is feasible for use in health and fitness facilities as its use does not require on-site medical expertise but does require trained staff and appropriate supervision. PPHS should be performed for new members and prospective users of these facilities at the time of enrollment following an informed consent process with subsequent facility access granted or withheld pending the need for medical clearance.
GENERAL RECOMMENDATIONS FOR ALL FACILITIES
A well-organized emergency response system is critical to providing a safe environment for exercise participants. Preventive measures, including proper signage, ongoing surveillance of facility safety, and member education, also are part of a comprehensive risk management plan. The next section provides recommendations based on the standards set forth by ACSM’s Health/Fitness Facility Standards and Guidelines (29) to prevent and appropriately respond to cardiovascular emergencies. Because health and fitness facilities vary greatly in their scope of offerings and clientele, the following elements should be incorporated at a level appropriate for each facility.
Emergency Response System
Health/fitness facilities must have a written emergency response plan that is reviewed quarterly and physically rehearsed at least twice annually (Table 4). The plan enables staff to respond to basic first aid and other emergency events in an appropriate and timely manner. The emergency response plan should address medical emergencies that are reasonably foreseeable in an exercise setting (e.g., common orthopedic injuries, sudden cardiac arrest, AMI, stroke, hypoglycemia, and heat illness) and must provide specific instructions for how an emergency situation is handled by the staff. The location of all emergency equipment, including automated external defibrillators (AEDs), emergency phone, and the entry/exit locations for access by emergency medical response system (EMS) personnel, should be clearly delineated. Facilities are encouraged to approach local health care or emergency medical personnel to assist with development or to review the emergency response system plan.
TABLE 4 -
Integral Components of an Emergency Response System
The written emergency response policies and procedures should contain the following:
• Conduct regular safety audits on all areas of the facility to reduce potential hazards and the frequency of emergency situations.
• Conduct staff training to improve the overall emergency readiness, including certification in first aid, CPR, and AED usage.
• Regularly inspect and maintain first aid kits and other medical equipment, including AEDs.
• Telephones or other emergency communication devices should be readily available and telephone numbers for emergency
assistance should be posted on or near the telephone.
• Designate a capable staff member to serve as the program coordinator with ultimate responsibility for the facility’s overall level
of emergency readiness.
• Written documentation is a crucial element of a comprehensive emergency response plan. Important documents, including
records of staff training, recertification, and the written emergency plan, should be kept in an area that is easily accessed by the staff.
• Have an incident report system in place. If an incident occurs, written documentation should be completed in a timely fashion
and maintained on file in accordance with the statute of limitations for where the facility is located. The components of an incident
report include the following:
Day, date, time, and location of the incident
Identity of the person(s) involved and their contact information
Identities of any witnesses and their contact information
Accounts of the incident provided by the witnesses
Names and job titles of employees involved in the incident
Names and job titles of responding staff
Detailed description of the incident
Actions taken
Outcomes |
AEDs
AEDs are computerized devices with voice and visual cues that guide exercise professionals and bystanders to defibrillate pulseless ventricular tachycardia or ventricular fibrillation (VF). AEDs detect life-threatening cardiac arrhythmias and then administer an electrical shock that can restore normal sinus rhythm. Early defibrillation is critical for the successful survival of VF, the most frequent type of SCD. Electrical defibrillation is the only effective treatment of VF, and delaying defibrillation rapidly reduces survival and increases the chance of neurological defects if the patient survives.
;)
SIDEBAR
In the absence of cardiopulmonary resuscitation (CPR), survival rates after witnessed VF decrease 10% to 12% with every minute of delay in defibrillation. When bystander CPR is provided, the decrease in survival averages 3% to 4% per minute from collapse to defibrillation (30,31). According to the American Heart Association (AHA), immediate recognition of sudden cardiac arrest and activation of the EMS, early CPR with an emphasis on chest compressions, and rapid defibrillation with an AED are the three most important steps that must occur within the initial moments of cardiac arrest (32).
Survival of ventricular tachycardia is highest when CPR is immediately delivered and defibrillation is attempted within 3 to 5 minutes (33). Accordingly, every facility with an AED should strive to get the response time from collapse caused by cardiac arrest to defibrillation to 3 minutes (optimal) to 5 minutes (acceptable) or less. The goal of a 3-minute response time should be used to determine the optimal number and placement of AEDs. Facilities with multiple floors should consider locating an AED on each floor. The AED should be inspected and maintained according to manufacturer’s specifications, and all related information should be carefully documented and maintained as a part of the facility’s emergency response system records. The emergency plan and the AED plan should be coordinated with the local EMS provider, a requirement of some states.
SIDEBAR
To achieve the recommended response time, health fitness facilities should provide AEDs in visible and accessible locations that the staff or public can reach within 1.5 minutes.
Staffed exercise facilities should have at least one staff member who is currently trained and certified in CPR and in the use of an AED on duty during all operating hours (29). Unstaffed facilities must have a public access defibrillator program in which either a fitness center member or an external emergency responder can respond from the time of collapse to defibrillation in 5 minutes or less (29).
Staff Credentials and Training
Health fitness facility staff should be appropriately trained and certified by an accredited organization that offers a basic life support course incorporating CPR, AED, and a hands-on practical skills assessment. Although basic life support training and certification by the American Heart Association and American Red Cross lasts for 1 to 2 years, CPR and AED skills can diminish with time, so retraining or practice sessions should be conducted at least every 6 months. Copies of all staff credentials and documentation of additional training should be kept on file and reviewed on a regular basis to confirm that all certifications are up to date.
Health fitness facility staff should be appropriately trained and certified by an accredited organization that offers a basic life support course incorporating CPR, AED, and a hands-on practical skills assessment.
Having a fitness certification does not ensure that exercise professionals are qualified to respond to emergency situations. Although some health fitness certifications are highly rigorous, requiring knowledge of first aid, PPHS, injury prevention, and current CPR/AED certification, other certifications require minimal training in these areas and do not require CPR/AED certification. Because there is no regulation of fitness certifications, attention must be paid to the credentials and qualifications of fitness center employees. Certification programs that do not require CPR/AED certification or do not provide training related to risk management should be considered insufficient or inadequate.
Staff should be encouraged to regularly attend conferences and engage in other forms of continuing education that address policies and procedures related to the facility’s emergency response and overall risk management.
Signage
Signage should have the proper appearance, readability, and placement to clearly display information in a manner that is easily understood by members and users. Signage should indicate the location of AED and first aid kits and include information on how to access those locations. There also should be signage on the emergency plan and whom to contact and how to use the AED, especially in facilities such as hotel fitness centers that are not staffed.
Member Training
Health and fitness facility members and users can play an important role in the prompt response to cardiovascular emergencies. Members should be provided with information about the location of emergency telephones and AEDs, taught signs and symptoms of adverse CVD events, and be encouraged to learn and practice basic bystander CPR. This training is particularly important at unstaffed facilities. Installing video surveillance and/or a panic button to activate EMS also should be a consideration in facilities that do not have staff on site.
Bottom Line
Providing a safe exercise environment is of the utmost importance in health fitness facilities. The overarching goal of this document is to reduce the likelihood of exercise-related cardiovascular complications and their adverse sequelae while simultaneously removing unnecessary barriers to widespread participation in regular PA. Developing an emergency plan, consistent staff training, and practicing emergency procedures should be emphasized in all health fitness facilities. In addition to providing a safe environment, it is important to remember that the risk of exercise-related adverse CVD events can be mitigated by adopting a progressive transitional phase of approximately 2 to 3 months during which exercise duration and intensity are gradually increased. It is strongly recommended that new clients who were previously sedentary begin with light- to moderate-intensity PA (2–3 METs) and gradually increase intensity over time provided they remain asymptomatic.
BRIDGING THE GAP
Exercise-related adverse cardiovascular events are rare; however, vigorous-intensity exercise has a small but measurable acute risk of cardiovascular complications. There are many steps that exercise professionals can take to provide a safe exercise environment for health fitness facility members/users. Proper screening can help identify individuals at high risk so they can be referred for medical clearance. A well-designed emergency response plan that includes quick access to AEDs, properly trained and credentialed staff, and regular drills to practice emergency procedures provides a high safety level for members/users.
References
1. Thompson PD, Baggish AL, Franklin B, Jaworski C, Riebe D. ACSM expert consensus statement for screening, staffing and emergency policies to prevent cardiovascular events at health fitness facilities.
Curr Sports Med Reports. 2020;19(6):223–31.
2. Balady GJ, Chaitman B, Driscoll D, et al. Recommendations for cardiovascular screening, staffing, and emergency policies at health/fitness facilities.
Circulation. 1998;97(22):2283–93.
3. Riebe D, Franklin BA, Thompson PD, et al. Updating ACSM’s recommendations for exercise preparticipation health screening.
Med Sci Sports Exerc. 2015;47(11):2473–9.
4. Loprinzi PD, Cardinal BJ. Association between biologic outcomes and objectively measured physical activity accumulated in ≥10-minute bouts and <10-minute bouts.
Am J Health Promo. 2013;27(3):143–51.
5. DeFina LF, Radford NB, Barlow CE, et al. Association of all-cause and cardiovascular mortality with high levels of physical activity and concurrent coronary artery calcification.
JAMA Cardiol. 2019;4(2):174–81.
6. Page RL, Husain S, White LY, et al. Cardiac arrest at exercise facilities: implications for placement of automated external defibrillators.
J Am Coll Cardiol. 2013;62(22):2102–9.
7. Myers J, Prakash M, Froelicher V, Do D, Partington S, Atwood JE. Exercise capacity and mortality among men referred for exercise testing.
N Engl J Med. 2002;346(11):793–801.
8. U.S. Department of Health and Human Services.
Physical Activity Guidelines for Americans. 2nd ed. 2018. Available from:
https://health.gov/sites/default/files/2019-09/Physical_Activity_Guidelines_2nd_edition.pdf.
9. 2018 Physical Activity Guidelines Advisory Committee.
2018 Physical Activity Guidelines Advisory Committee Scientific Report. Washington (DC): U.S. Department of Health and Human Services; 2018. Available from:
https://health.gov/our-work/physical-activity/current-guidelines/scientific-report.
10. Biswas A, Oh PI, Faulkner GE, et al. Sedentary time and its association with risk for disease incidence, mortality, and hospitalization in adults: a systematic review and meta-analysis.
Ann Intern Med. 2015;162(2):123–32.
11. Thompson PD, Franklin BA, et al; American College of Sports Medicine. Exercise and acute cardiovascular events: placing the risks into perspective: a scientific statement from the American Heart Association Council on Nutrition, Physical Activity, and Metabolism and the Council on Clinical Cardiology.
Circulation. 2007;115(17):2358–68.
12. Giri S, Thompson PD, Kiernan FJ, et al. Clinical and angiographic characteristics of exertion-related acute myocardial infarction.
JAMA. 1999;282(18):1731–6.
13. Hossack K, Hartwig R. Cardiac arrest associated with supervised cardiac rehabilitation.
J Cardiac Rehabil. 1982;2(5):402–8.
14. Franklin BA, Thompson PD, Al-Zaiti SS, et al. Exercise-related acute cardiovascular events and potential deleterious adaptations following long-term exercise training: placing the risks into perspective — an update.
Circulation. 2020;141:e705–36.
15. Eckart RE, Shry EA, Burke AP, et al. Sudden death in young adults: an autopsy-based series of a population undergoing active surveillance.
J Am Coll Cardiol. 2011;58(12):1254–61.
16. Franklin BA. Preventing exercise-related cardiovascular events: is a medical examination more urgent for physical activity or inactivity?
Circulation. 2014;129:1081–4.
17. Albert CM, Mittleman MA, Chae CU, Lee I, Hennekens CH, Manson JE. Triggering of sudden death from cardiac causes by vigorous exertion.
N Engl J Med. 2000;343(19):1355–61.
18. Mittleman MA, Maclure M, Tofler GH, Sherwood JB, Goldberg RJ, Muller JE. Triggering of acute myocardial infarction by heavy physical exertion—protection against triggering by regular exertion.
N Engl J Med. 1993;329(23):1677–83.
19. Harmon KG, Asif IM, Maleszewski JJ, et al. Incidence, cause, and comparative frequency of sudden cardiac death in national collegiate athletic association athletes: a decade in review.
Circulation. 2015;132(1):10–9.
20. Burtscher M. Risk and protective factors for sudden cardiac death during leisure activities in the mountains: an update.
Heart Lung Circ. 2017;26(8):757–62.
21. Mohammad MA, Koul S, Rylance R, et al. Association of weather with day-to-day incidence of myocardial infarction: a SWEDEHEART nationwide observational study.
JAMA Cardiol. 2018;3(11):1081–9.
22. Pandolf KB, Cafarelli E, Noble BJ, Metz KF. Hyperthermia: effect on exercise prescription.
Arch Phys Med Rehabil. 1975;56(12):524–6.
23. Ullal AJ, Abdelfattah RS, Ashley EA, Froelicher VF. Hypertrophic cardiomyopathy as a cause of sudden cardiac death in the young: a meta-analysis.
Am J Med. 2016;129(5):486–496. e2.
24. Waller BF, Roberts WC. Sudden death while running in conditioned runners aged 40 years or over.
Am J Cardiol. 1980;45(6):1292–300.
25. Whang W, Manson JE, Hu FB, et al. Physical exertion, exercise, and sudden cardiac death in women.
JAMA. 2006;295(12):1399–403.
26. Wewege MA, Ahn D, Yu J, Liou K, Keech A. High-intensity interval training for patients with cardiovascular disease—is it safe? A systematic review.
J Am Heart Assoc. 2018;7(21):e009305.
27. Hannan AL, Hing W, Simas V, et al. High-intensity interval training versus moderate-intensity continuous training within cardiac rehabilitation: a systematic review and meta-analysis.
Open Access J Sports Med. 2018;9:1–17.
28. Quindry JC, Franklin BA, Chapman M, Humphrey R, Mathis S. Benefits and risks of high-intensity interval training in patients with coronary artery disease.
Am J Cardiol. 2019;123:1370–7.
29. Sanders M, editor.
ACSM’s Health/Fitness Facility Standards and Guidelines, 5th ed. Champaign (IL): Human Kinetics; 2019.
30. Valenzuela TD, Roe DJ, Cretin S, Spaite DW, Larsen MP. Estimating effectiveness of cardiac arrest interventions: a logistic regression survival model.
Circulation. 1997;96(10):3308–13.
31. Waalewijn RA, Tijssen JG, Koster RW. Bystander initiated actions in out-of-hospital cardiopulmonary resuscitation: results from the Amsterdam Resuscitation Study (ARRESUST).
Resuscitation. 2001;50(3):273–9.
32. Kleinman ME, Brennan EE, Goldberger ZD, et al. Part 5: adult basic life support and cardiopulmonary resuscitation quality: 2015 American Heart Association Guidelines Update for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care.
Circulation. 2015;132(18 suppl 2):S414–35.
33. Sasson C, Rogers MA, Dahl J, Kellermann AL. Predictors of survival from out-of-hospital cardiac arrest: a systematic review and meta-analysis.
Circ-Cardiovasc Qual. 2010;3(1):63–81.
Recommended Reading
Sanders M, editor. ACSM’s Health/Fitness Facility Standards and Guidelines, 5th ed. Champaign (IL): Human Kinetics; 2019.