EXERCISE STRESS TESTING FOR EVALUATING SYNCOPE IN ATHLETES: A NARRATIVE REVIEW
Abstract
Objectives: Syncope in athletes presents a complex diagnostic challenge requiring systematic evaluation to differentiate benign neurally-mediated causes from potentially life-threatening cardiac conditions. Unrecognized cardiovascular disease in athletes can lead to sudden cardiac death, making accurate risk stratification essential for athlete safety and appropriate return-to-play decisions. We aim to provide a comprehensive synthesis of current evidence regarding the indications, protocols, diagnostic yield, and limitations of exercise stress testing in athletes presenting with syncope.
Methods: We conducted a narrative literature review of PubMed databases from 2004-2025, focusing on studies involving athletic populations and recent consensus statements from major cardiovascular and sports medicine organizations. Evidence was synthesized from observational studies, clinical guidelines, and expert consensus documents.
Key findings: Exercise stress testing is strongly recommended for all athletes with exertional syncope, with sport-specific, maximal-effort protocols yielding arrhythmic or ischemic findings in 15-25% of cases. Negative predictive values approach 95% when proper protocols are employed, significantly reducing the probability of exercise-induced life-threatening events, though residual risk remains. Current evidence supports individualized testing protocols rather than generic clinical protocols designed for ischemia detection. Integration with comprehensive clinical assessment, ECG, echocardiography, and risk factor evaluation optimizes diagnostic accuracy and clinical decision-making.
Conclusions: Sport-specific, effortful exercise stress testing serves as a pivotal diagnostic tool and safety gatekeeper in athletic syncope evaluation. When integrated within systematic algorithms it enables accurate risk stratification, specialist referral, and evidence-based return-to-play decisions. Future research should focus on protocol validation, long-term outcome studies, and integration of emerging technologies for further enhancement of diagnostic precision.
References
Aydin, M. A., Salukhe, T. V., Wilke, I., & Willems, S. (2010). Management and therapy of vasovagal syncope: A review. World Journal of Cardiology, 2(10), 308. https://doi.org/10.4330/wjc.v2.i10.308
Balady, G., Arena, R., Sietsema, K. E., Myers, J., Coke, L. A., Fletcher, G. F., Forman, D. E., Franklin, B. A., Guazzi, M., Gulati, M., Keteyian, S. J., Lavie, C. J., Macko, R. F., Mancini, D., & Milani, R. V. (2010). Clinician’s Guide to Cardiopulmonary Exercise Testing in Adults [Review of Clinician’s Guide to Cardiopulmonary Exercise Testing in Adults]. Circulation, 122(2), 191. Lippincott Williams & Wilkins. https://doi.org/10.1161/cir.0b013e3181e52e69
Baswaraj, D., & Flaker, G. (2024). Syncope in Athletes: A Prelude to Sudden Cardiac Death? PubMed, 121(1), 52. https://pubmed.ncbi.nlm.nih.gov/38404441
Bickel, T., Gunasekaran, P., Murtaza, G., Gopinathannair, R., Gunda, S., & Lakkireddy, D. (2019). Sudden Cardiac Death in Famous Athletes, Lessons Learned, Heterogeneity in Expert Recommendations and Pitfalls of Contemporary Screening Strategies [Review of Sudden Cardiac Death in Famous Athletes, Lessons Learned, Heterogeneity in Expert Recommendations and Pitfalls of Contemporary Screening Strategies]. Journal of Atrial Fibrillation, 12(4). https://doi.org/10.4022/jafib.2193
Brignole, M., Moya, A., de Lange, F. J., Deharo, J.-C., Elliott, P. M., Fanciulli, A., Fedorowski, A., Furlan, R., Kenny, R. A., Martiın, A., Probst, V., Reed, M. J., Rice, C., Sutton, R., Sutton, R. E., Ungar, A., & van Dijk, J. G. (2018). 2018 ESC Guidelines for the diagnosis and management of syncope. Kardiologia Polska, 76(8), 1119. https://doi.org/10.5603/kp.2018.0161
Brignole, M., Moyá, A., Lange, F. J. de, Deharo, J., Elliott, P., Fanciulli, A., Fedorowski, A., Furlan, R., Kenny, R. A., Martı́n, A., Probst, V., Reed, M. J., Rice, C., Sutton, R., Ungar, A., Dijk, J. G. van, Torbicki, A., Moreno, J., Aboyans, V., … Zamorano, J. L. (2018). Practical Instructions for the 2018 ESC Guidelines for the diagnosis and management of syncope. European Heart Journal, 39(21). https://doi.org/10.1093/eurheartj/ehy071
Chandler, S. F., Hylind, R. J., & Abrams, D. J. (2019). Exercise Stress Testing: Diagnostic Utility in the Evaluation of Long QT Syndrome. In Springer eBooks (p. 219). Springer Nature. https://doi.org/10.1007/978-3-030-16818-6_30
Colivicchi, F., Ammirati, F., & Santini, M. (2004). Epidemiology and prognostic implications of syncope in young competing athletes. European Heart Journal, 25(19), 1749. https://doi.org/10.1016/j.ehj.2004.07.011
Corrado, D., Basso, C., Pavei, A., Michieli, P., Schiavon, M., & Thiene, G. (2006). Trends in Sudden Cardiovascular Death in Young Competitive Athletes After Implementation of a Preparticipation Screening Program. JAMA, 296(13), 1593. https://doi.org/10.1001/jama.296.13.1593
Corrado, D., Drezner, J. A., D’Ascenzi, F., & Zorzi, A. (2019). How to evaluate premature ventricular beats in the athlete: critical review and proposal of a diagnostic algorithm [Review of How to evaluate premature ventricular beats in the athlete: critical review and proposal of a diagnostic algorithm]. British Journal of Sports Medicine, 54(19), 1142. BMJ. https://doi.org/10.1136/bjsports-2018-100529
Cosío-Lima, L., Adlof, L., Simpson, J. D., Crawley, A., & Lee, Y. (2020). Athletes ECG Stress Characteristics in Division II College Athletes: A Preliminary Analysis. Journal of Science in Sport and Exercise, 2(2), 183. https://doi.org/10.1007/s42978-020-00057-2
D’Ascenzi, F., Zorzi, A., Sciaccaluga, C., Berrettini, U., Mondillo, S., & Brignole, M. (2020). Syncope in the Young Adult and in the Athlete: Causes and Clinical Work-up to Exclude a Life-Threatening Cardiac Disease. Journal of Cardiovascular Translational Research, 13(3), 322. https://doi.org/10.1007/s12265-020-09989-0
Dores, H., Dinis, P., Viegas, J., & Freitas, A. (2024). Preparticipation Cardiovascular Screening of Athletes: Current Controversies and Challenges for the Future [Review of Preparticipation Cardiovascular Screening of Athletes: Current Controversies and Challenges for the Future]. Diagnostics, 14(21), 2445. Multidisciplinary Digital Publishing Institute. https://doi.org/10.3390/diagnostics14212445
Drezner, J. A., Ackerman, M. J., Anderson, J., Ashley, E. A., Asplund, C. A., Baggish, A. L., Börjesson, M., Cannon, B. C., Corrado, D., DiFiori, J. P., Fischbach, P., Froelicher, V. F., Harmon, K. G., Heidbüchel, H., Marek, J. C., Owens, D. S., Paul, S., Pelliccia, A., Prutkin, J. M., … Wilson, M. G. (2013). Electrocardiographic interpretation in athletes: the ‘Seattle Criteria.’ British Journal of Sports Medicine, 47(3), 122. https://doi.org/10.1136/bjsports-2012-092067
Edvardsen, E., Hem, E., & Anderssen, S. A. (2014). End Criteria for Reaching Maximal Oxygen Uptake Must Be Strict and Adjusted to Sex and Age: A Cross-Sectional Study. PLoS ONE, 9(1). https://doi.org/10.1371/journal.pone.0085276
Fletcher, G. F., Ades, P. A., Kligfield, P., Arena, R., Balady, G. J., Bittner, V. A., Coke, L. A., Fleg, J. L., Forman, D. E., Gerber, T. C., Gulati, M., Madan, K., Rhodes, J., Thompson, P. D., & Williams, M. A. (2013). Exercise Standards for Testing and Training A Scientific Statement From the American Heart Association. https://doi.org/ 10.1161/cir.0b013e31829b5b44
Frazier‐Mills, C., Johnson, L. C., Xia, Y., Rosemas, S., Franco, N., & Pokorney, S. D. (2022). Syncope Recurrence and Downstream Diagnostic Testing after Insertable Cardiac Monitor Placement for Syncope. Diagnostics, 12(8), 1977. https://doi.org/10.3390/diagnostics12081977
Gerche, A. L., Baggish, A. L., Knuuti, J., Prior, D. L., Sharma, S., Heidbüchel, H., & Thompson, P. M. (2013). Cardiac Imaging and Stress Testing Asymptomatic Athletes to Identify Those at Risk of Sudden Cardiac Death [Review of Cardiac Imaging and Stress Testing Asymptomatic Athletes to Identify Those at Risk of Sudden Cardiac Death]. JACC. Cardiovascular Imaging, 6(9), 993. Elsevier BV. https://doi.org/10.1016/j.jcmg.2013.06.003
Graziano, F., Zorzi, A., Ungaro, S., Bauce, B., Rigato, I., Cipriani, A., Marra, M. P., Pilichou, K., Basso, C., & Corrado, D. (2024). The 2023 European Task Force Criteria for Diagnosis of Arrhythmogenic Cardiomyopathy: Historical Background and Review of Main Changes [Review of The 2023 European Task Force Criteria for Diagnosis of Arrhythmogenic Cardiomyopathy: Historical Background and Review of Main Changes]. Reviews in Cardiovascular Medicine, 25(9). IMR Press. https://doi.org/10.31083/j.rcm2509348
Halliwill, J. R., Sieck, D. C., Romero, S. A., Buck, T. M., & Ely, M. R. (2013). Blood pressure regulation X: what happens when the muscle pump is lost? Post-exercise hypotension and syncope [Review of Blood pressure regulation X: what happens when the muscle pump is lost? Post-exercise hypotension and syncope]. European Journal of Applied Physiology, 114(3), 561. Springer Science+Business Media. https://doi.org/10.1007/s00421-013-2761-1
Hastings, J. L., & Levine, B. D. (2012). Syncope in the Athletic Patient [Review of Syncope in the Athletic Patient]. Progress in Cardiovascular Diseases, 54(5), 438. Elsevier BV. https://doi.org/10.1016/j.pcad.2012.02.003
Innocentiis, C. D., Ricci, F., Khanji, M. Y., Aung, N., Tana, C., Verrengia, E., Petersen, S. E., & Gallina, S. (2018). Athlete’s Heart: Diagnostic Challenges and Future Perspectives [Review of Athlete’s Heart: Diagnostic Challenges and Future Perspectives]. Sports Medicine, 48(11), 2463. Springer Science+Business Media. https://doi.org/10.1007/s40279-018-0985-2
Jain, C. C., & Borlaug, B. A. (2020). Performance and Interpretation of Invasive Hemodynamic Exercise Testing [Review of Performance and Interpretation of Invasive Hemodynamic Exercise Testing]. CHEST Journal, 158(5), 2119. Elsevier BV. https://doi.org/10.1016/j.chest.2020.05.552
Khattab, E., Velidakis, N., Gkougkoudi, E., & Kadoglou, N. P. E. (2023). Exercise-Induced Pulmonary Hypertension: A Valid Entity or Another Factor of Confusion? [Review of Exercise-Induced Pulmonary Hypertension: A Valid Entity or Another Factor of Confusion?]. Life, 13(1), 128. Multidisciplinary Digital Publishing Institute. https://doi.org/10.3390/life13010128
Koene, R. J., Adkisson, W. O., & Benditt, D. G. (2017). Syncope and the risk of sudden cardiac death: Evaluation, management, and prevention [Review of Syncope and the risk of sudden cardiac death: Evaluation, management, and prevention]. Journal of Arrhythmia, 33(6), 533. Elsevier BV. https://doi.org/10.1016/j.joa.2017.07.005
Lampert, R., Chung, E. H., Ackerman, M. J., Arroyo, A. R., Darden, D., Deo, R., Dolan, J., Etheridge, S. P., Gray, B. R., Harmon, K. G., James, C. A., Kim, J. H., Krahn, A. D., La Gerche, A., Link, M. S., MacIntyre, C., Mont, L., Salerno, J. C., & Shah, M. J. (2024). HRS expert consensus statement on arrhythmias in the athlete: Evaluation, treatment, and return to play. https://doi.org/10.1016/j.hrthm.2024.05.018
Lampert, R., Olshansky, B., Heidbüchel, H., Lawless, C. E., Saarel, E. V., Ackerman, M. J., Calkins, H., Estes, N. A. M., Link, M. S., Maron, B. J., Marcus, G. M., Scheinman, M. M., Wilkoff, B. L., Zipes, D. P., Berul, C. I., Cheng, A., Jordaens, L., Law, I. H., Loomis, M., … Cannom, D. S. (2017, June 5). Safety of Sports for Athletes With Implantable Cardioverter-Defibrillators. In Circulation (Vol. 135, Issue 23, p. 2310). Lippincott Williams & Wilkins. https://doi.org/10.1161/circulationaha.117.027828
Lancellotti, P., Pellikka, P. A., Budts, W., Chaudhry, F. A., Donal, E., Dulgheru, R., Edvardsen, T., Garbi, M., Ha, J., Kane, G. C., Kreeger, J., Mertens, L., Pîbarot, P., Picaño, E., Ryan, T., Tsutsui, J. M., & Varga, A. (2016). The clinical use of stress echocardiography in non-ischaemic heart disease: recommendations from the European Association of Cardiovascular Imaging and the American Society of Echocardiography [Review of The clinical use of stress echocardiography in non-ischaemic heart disease: recommendations from the European Association of Cardiovascular Imaging and the American Society of Echocardiography]. European Heart Journal - Cardiovascular Imaging, 17(11), 1191. Oxford University Press. https://doi.org/10.1093/ehjci/jew190
Lee, C., Dow, S., Shah, K., Henkin, S., & Taub, C. C. (2023). Complications of exercise and pharmacologic stress echocardiography [Review of Complications of exercise and pharmacologic stress echocardiography]. Frontiers in Cardiovascular Medicine, 10. Frontiers Media. https://doi.org/10.3389/fcvm.2023.1228613
Link, M. S., & Estes, N. A. M. (2007). How to Manage Athletes with Syncope [Review of How to Manage Athletes with Syncope]. Cardiology Clinics, 25(3), 457. Elsevier BV. https://doi.org/10.1016/j.ccl.2007.07.005
Ljungqvist, A., Jenoure, P., Engebretsen, L., Alonso, J. M., Bahr, R., Clough, A., Bondt, G. de, Dvořák, J., Maloley, R., Matheson, G. O., Meeuwisse, W., Meijboom, E. J., Mountjoy, M., Pelliccia, A., Schwellnus, M., Sprumont, D., Schamasch, P., Gauthier, J.-B., Dubi, C., … Thill, C. (2009). The International Olympic Committee (IOC) Consensus Statement on periodic health evaluation of elite athletes March 2009. British Journal of Sports Medicine, 43(9), 631. https://doi.org/10.1136/bjsm.2009.064394
Magalhães-Ribeiro, C., & Freitas, J. (2016). Syncope in the young athlete: Assessment of prognosis in subjects with hypertrophic cardiomyopathy [Review of Syncope in the young athlete: Assessment of prognosis in subjects with hypertrophic cardiomyopathy]. Revista Portuguesa de Cardiologia, 35, 433. Elsevier BV. https://doi.org/10.1016/j.repc.2016.04.007
Maron, B. J., Udelson, J. E., Bonow, R. O., Nishimura, R. A., Ackerman, M. J., Estes 3rd, N. A., Cooper Jr, L. T., Link, M. S., & Maron, M. S. (2015). Eligibility and disqualification recommendations for competitive athletes with cardiovascular abnormalities: Task Force 3: hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy and other cardiomyopathies, and myocarditis: a scientific statement from the American Heart Association and American College of Cardiology. https://doi.org/10.1161/cir.0000000000000239
Maron, B., Levine, B., Washington, R., Baggish, A., Kovacs, R., & Maron, M. (2015). Eligibility and disqualification recommendations for competitive athletes with cardiovascular abnormalities: Task Force 2: preparticipation screening for cardiovascular disease in competitive athletes: a scientific statement from the American Heart Association and American College of Cardiology. https://doi.org/10.1161/cir.0000000000000238
McAward, K., & Moriarity, J. (2005). Exertional syncope and presyncope: faint signs of underlying problems. The Physician and Sportsmedicine, 33(11), 7. https://doi.org/10.3810/psm.2005.11.245
Melby, D. P., Cytron, J. A., & Benditt, D. G. (2004). New approaches to the treatment and prevention of neurally mediated reflex (neurocardiogenic) syncope. Current Cardiology Reports, 6(5), 385. https://doi.org/10.1007/s11886-004-0042-7
Mündel, T., Perry, B. G., Ainslie, P. N., Thomas, K. N., Sikken, E. L. G., Cotter, J. D., & Lucas, S. J. E. (2015). Postexercise orthostatic intolerance: influence of exercise intensity. Experimental Physiology, 100(8), 915. https://doi.org/10.1113/ep085143
Natarajan, B., & Nikore, V. (2006). Syncope and near syncope in competitive athletes. Current Sports Medicine Reports, 5(6), 300. https://doi.org/10.1007/s11932-006-0057-5
Obeyesekere, M., Klein, G. J., Modi, S., Leong‐Sit, P., Gula, L. J., Yee, R., Skanes, A. C., & Krahn, A. D. (2011). How to Perform and Interpret Provocative Testing for the Diagnosis of Brugada Syndrome, Long-QT Syndrome, and Catecholaminergic Polymorphic Ventricular Tachycardia [Review of How to Perform and Interpret Provocative Testing for the Diagnosis of Brugada Syndrome, Long-QT Syndrome, and Catecholaminergic Polymorphic Ventricular Tachycardia]. Circulation Arrhythmia and Electrophysiology, 4(6), 958. Lippincott Williams & Wilkins. https://doi.org/10.1161/circep.111.965947
O’Connor, F. G., Levine, B. D., Childress, M. A., Asplundh, C. A., & Oriscello, R. G. (2009). Practical Management: A Systematic Approach to the Evaluation of Exercise-Related Syncope in Athletes. Clinical Journal of Sport Medicine, 19(5), 429. https://doi.org/10.1097/jsm.0b013e3181b732c3
Petek, B. J., Gustus, S., & Wasfy, M. M. (2021). Cardiopulmonary Exercise Testing in Athletes: Expect the Unexpected. Current Treatment Options in Cardiovascular Medicine, 23(7). https://doi.org/10.1007/s11936-021-00928-z
Peterson, D. F., Kucera, K., Thomas, L. C., Maleszewski, J., Siebert, D., Lopez-Anderson, M., Zigman, M., Schattenkerk, J., Harmon, K. G., & Drezner, J. A. (2020). Aetiology and incidence of sudden cardiac arrest and death in young competitive athletes in the USA: a 4- year prospective study. https://doi.org/10.1136/bjsports-2020-102666
Pugh, A., Bourke, J., & Kunadian, V. (2012). Sudden cardiac death among competitive adult athletes: a review [Review of Sudden cardiac death among competitive adult athletes: a review]. Postgraduate Medical Journal, 88(1041), 382. Oxford University Press. https://doi.org/10.1136/postgradmedj-2011-130215
Rocha, E. A., Kubrusly, B. S., Gurgel, A. de A. A., Pinho, L. G. B., Farias, A. G. P., Coimbra, V. O., Gondim, P. S. P., Rocha, M. C. T., Rocha, M. E. Q. A., Pereira, F. T. M., Marques, V. R. B., Farias, R. L., & Rocha, E. A. (2024). The Tilt Test in the Assessment of Syncope and Pre-syncope. Effective and safe? Analysis of a Series of 2364 Patients over 6 Years. Journal of Cardiac Arrhythmias, 37. https://doi.org/10.24207/jca.v37i1.3490
Roston, T. M., Kallas, D., Davies, B., Franciosi, S., Souza, A. M. D., Laksman, Z., Sanatani, S., & Krahn, A. D. (2021). Burst Exercise Testing Can Unmask Arrhythmias in Patients With Incompletely Penetrant Catecholaminergic Polymorphic Ventricular Tachycardia [Review of Burst Exercise Testing Can Unmask Arrhythmias in Patients With Incompletely Penetrant Catecholaminergic Polymorphic Ventricular Tachycardia]. JACC. Clinical Electrophysiology, 7(4), 437. Elsevier BV. https://doi.org/10.1016/j.jacep.2021.02.013
Sharma, S., Drezner, J. A., Baggish, A. L., Papadakis, M., Wilson, M. G., Prutkin, J. M., Gerche, A. L., Ackerman, M. J., Börjesson, M., Salerno, J. C., Asif, I. M., Owens, D. S., Chung, E. H., Emery, M. S., Froelicher, V. F., Heidbüchel, H., Adamuz, C., Asplund, C. A., Cohen, G., … Corrado, D. (2017). International Recommendations for Electrocardiographic Interpretation in Athletes [Review of International Recommendations for Electrocardiographic Interpretation in Athletes]. Journal of the American College of Cardiology, 69(8), 1057. Elsevier BV. https://doi.org/10.1016/j.jacc.2017.01.015
Shen, W., Sheldon, R. S., Benditt, D. G., Cohen, M. I., Forman, D. E., Goldberger, Z. D., Grubb, B. P., Hamdan, M. H., Krahn, A. D., Link, M. S., Olshansky, B., Raj, S. R., Sandhu, R. K., Sorajja, D., Sun, B., & Yancy, C. W. (2017). 2017 ACC/AHA/HRS Guideline for the Evaluation and Management of Patients With Syncope: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society [Review of 2017 ACC/AHA/HRS Guideline for the Evaluation and Management of Patients With Syncope: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society]. Circulation, 136(5). Lippincott Williams & Wilkins. https://doi.org/10.1161/cir.0000000000000499
van Dijk, N., Quartieri, F., Blanc, J.-J., Garcia-Civera, R., Brignole, M., Moya, A., Wieling, W., & Investigators, P.-T. (2006). Effectiveness of Physical Counterpressure Maneuvers in Preventing Vasovagal Syncope: The Physical Counterpressure Manoeuvres Trial (PC-Trial). Journal of the American College of Cardiology, 48(8), 1652. https://doi.org/10.1016/j.jacc.2006.06.059
Van Hare, G., Ackerman, M., Evangelista, J., Kovacs, R., Myerburg, R., Shafer, K., Warnes, C., & Washington, R. (2015). Eligibility and disqualification recommendations for competitive. https://doi.org/10.1161/cir.0000000000000240
Whitman, M., D’souza, A. S., Jenkins, C., Sabapathy, S., & Challa, P. (2021). Safety and Efficacy of Scientist Led Exercise Stress Testing for Arrhythmia Provocation and Chronotropic Competence. The American Journal of Cardiology, 154, 63. https://doi.org/10.1016/j.amjcard.2021.05.042
Williford, N. N., Ward, C., & Olshansky, B. (2018). Evaluation and Management of Syncope: Comparing the Guidelines of the American College of Cardiology/American Heart Association/Heart Rhythm Society and the European Society of Cardiology. Journal of Innovations in Cardiac Rhythm Management, 9(12), 3457. https://doi.org/10.19102/icrm.2018.091208
Zipes, D. P., Link, M. S., Ackerman, M. J., Kovacs, R. J., Myerburg, R. J., & Estes, N. A. M. (2015). Eligibility and Disqualification Recommendations for Competitive Athletes With Cardiovascular Abnormalities: Task Force 9: Arrhythmias and Conduction Defects [Review of Eligibility and Disqualification Recommendations for Competitive Athletes With Cardiovascular Abnormalities: Task Force 9: Arrhythmias and Conduction Defects]. Circulation, 132(22). Lippincott Williams & Wilkins. https://doi.org/10.1161/cir.0000000000000245
Views:
52
Downloads:
29
Copyright (c) 2025 Patryk Macuk, Anna Leśniewska, Julia Tarnowska, Filip Szydzik, Bartosz Żegleń, Michał Gniedziejko, Jakub Roszak, Oliwia Sójkowska-Sławińska, Aleksandra Gradek
This work is licensed under a Creative Commons Attribution 4.0 International License.
All articles are published in open-access and licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0). Hence, authors retain copyright to the content of the articles.
CC BY 4.0 License allows content to be copied, adapted, displayed, distributed, re-published or otherwise re-used for any purpose including for adaptation and commercial use provided the content is attributed.
