Shift work and overtime have been implicated as important work-related risk factors for cardiovascular disease (CVD). Many firefighters who contractually work on a 24-hr work schedule, often do overtime (additional 24-hr shifts) which can result in working multiple, consecutive 24-hr shifts. Very little research has been conducted on firefighters at work that examines the impact of performing consecutive 24-hr shifts on cardiovascular physiology. Also, there have been no standard field methods for assessing in firefighters the cardiovascular changes that result from 24-hr shifts, what we call “cardiovascular strain”. The objective of this study, as the first step toward elucidating the role of very long (> 48 hrs) shifts in the development of CVD in firefighters, is to develop and describe a theoretical framework for studying cardiovascular strain in firefighters on very long shifts (i.e., > 2 consecutive 24-hr shifts). The developed theoretical framework was built on an extensive literature review, our recently completed studies with firefighters in Southern California, e-mail and discussions with several firefighters on their experiences of consecutive shifts, and our recently conducted feasibility study in a small group of firefighters of several ambulatory cardiovascular strain biomarkers (heart rate, heart rate variability, blood pressure, salivary cortisol, and salivary C-reactive protein). The theoretical framework developed in this study will facilitate future field studies on consecutive 24-hr shifts and cardiovascular health in firefighters. Also it will increase our understanding of the mechanisms by which shift work or long work hours can affect CVD, particularly through CVD biological risk factors, and thereby inform policy about sustainable work and rest schedules for firefighters.

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Citations to this article as recorded by  

• The Cyclical Battle of Insomnia and Mental Health Impairment in Firefighters: A Narrative Review
  Angelia M. Holland-Winkler, Daniel R. Greene, Tiffany J. Oberther
  Journal of Clinical Medicine.2024; 13(8): 2169.     CrossRef
• Working Hours, Shift, and Remote Work by Industry and Occupation in U.S. Full-time Workers
  Guang X. Chen
  Workplace Health & Safety.2024; 72(9): 392.     CrossRef
• Comparing actigraphy and diary to measure daily and average sleep in firefighters: a Bland–Altman analysis
  Ryan Marmis, Logan McGoldrick-Ruth, Monica R. Kelly, Patricia L. Haynes
  Journal of Clinical Sleep Medicine.2024; 20(4): 497.     CrossRef
• High-Performance Programs for First Responders: Considerations and Potential Benefits of Implementation
  Robert G. Lockie, J. Jay Dawes
  Strength & Conditioning Journal.2024; 46(4): 447.     CrossRef
• Adapting shift work schedules for sleep quality, sleep duration, and sleepiness in shift workers
  Gerben Hulsegge, Pieter Coenen, Gregg M Gascon, Manisha Pahwa, Birgit Greiner, Ciarán Bohane, Imelda S Wong, Juha Liira, Rachel Riera, Daniela V Pachito
  Cochrane Database of Systematic Reviews.2023;[Epub]     CrossRef
• COVID-19–Related Medical Vulnerability and Mental Health Outcomes Among US First Responders
  Antoine Lebeaut, Maya Zegel, Samuel J. Leonard, Nathaniel A. Healy, Elizabeth A. Anderson-Fletcher, Anka A. Vujanovic
  Journal of Occupational & Environmental Medicine.2023; 65(5): e283.     CrossRef
• Exercise Habits and Resources for Southeastern US Firefighters
  Philip Agostinelli, Rebecca Hirschhorn, JoEllen Sefton
  Journal of Occupational & Environmental Medicine.2023; 65(5): e351.     CrossRef
• Synergistic interaction between long shifts and short rest periods on depression in shift workers: A cross‐sectional study from Korea
  Sungjin Park, Jongin Lee, June‐Hee Lee
  American Journal of Industrial Medicine.2023; 66(11): 977.     CrossRef
• The effect of extended shift work on autonomic function in occupational settings: A systematic review and meta-analysis
  Jacob D Jelmini, Jeremy Ross, Lauren N Whitehurst, Nicholas R Heebner
  Journal of Occupational Health.2023;[Epub]     CrossRef
• Falls in older persons living alone: the role of individual, social and environmental factors
  Isabel Lage, Fátima Braga, Manuela Almendra, Filipe Meneses, Laetitia Teixeira, Odete Araujo
  Enfermería Clínica (English Edition).2022; 32(6): 396.     CrossRef
• Caídas en personas mayores que viven solas: el papel de los factores individuales, sociales y medioambientales
  Isabel Lage, Fátima Braga, Manuela Almendra, Filipe Meneses, Laetitia Teixeira, Odete Araujo
  Enfermería Clínica.2022; 32(6): 396.     CrossRef
• The Wildland Firefighter Exposure and Health Effect (WFFEHE) Study: Rationale, Design, and Methods of a Repeated-Measures Study
  Kathleen M Navarro, Corey R Butler, Kenneth Fent, Christine Toennis, Deborah Sammons, Alejandra Ramirez-Cardenas, Kathleen A Clark, David C Byrne, Pamela S Graydon, Christa R Hale, Andrea F Wilkinson, Denise L Smith, Marissa C Alexander-Scott, Lynne E Pin
  Annals of Work Exposures and Health.2022; 66(6): 714.     CrossRef
• Low testosterone and cardiometabolic risks in a real-world study of US male firefighters
  Sushant M. Ranadive, Adriana Lofrano-Porto, Edgard M. K. V. K. Soares, Lauren Eagan, Luiz Guilherme Grossi Porto, Denise L. Smith
  Scientific Reports.2021;[Epub]     CrossRef
• Enhancing adaptive performance in emergency response: Empowerment practices and the moderating role of tempo balance
  David Huntsman, Alex Greer, Haley Murphy, Steven Haynes
  Safety Science.2021; 134: 105060.     CrossRef
• Mental Health of Canadian Firefighters: The Impact of Sleep
  Heidi Cramm, Rachel Richmond, Laleh Jamshidi, Megan Edgelow, Dianne Groll, Rose Ricciardelli, Joy Christine MacDermid, Michael Keiley, R. Nicholas Carleton
  International Journal of Environmental Research and Public Health.2021; 18(24): 13256.     CrossRef
• A feasibility study of a WhatsApp-delivered Transtheoretical Model-based intervention to promote healthy eating habits for firefighters in Hong Kong: a cluster randomized controlled trial
  Wing Man Ng, Kin Cheung
  Trials.2020;[Epub]     CrossRef
• The influence of cardiometabolic risk factors on cardiorespiratory fitness in volunteer Chilean firefighters
  Fernando Espinoza, Pedro Delgado‐Floody, Cristian Martínez‐Salazar, Daniel Jerez‐Mayorga, Iris Paola Guzmán‐Guzmán, Felipe Caamaño‐Navarrete, Rodrigo Ramirez‐Campillo, Claudio Chamorro, Christian Campos‐Jara
  American Journal of Human Biology.2019;[Epub]     CrossRef
• Effects of Wrist Cooling on Recovery From Exercise-Induced Heat Stress With Firefighting Personal Protective Equipment
  Emily Schlicht, Ronald Caruso, Kelsey Denby, Alexs Matias, Monique Dudar, Stephen J. Ives
  Journal of Occupational & Environmental Medicine.2018; 60(11): 1049.     CrossRef
• One‐year weight change and long‐term sickness absence in professional firefighters
  BongKyoo Choi
  American Journal of Industrial Medicine.2017; 60(6): 548.     CrossRef
• Predictors of health‐related quality of life among industrial workers: A descriptive correlational study
  Malakeh Z. Malak
  Nursing & Health Sciences.2017; 19(2): 204.     CrossRef
• Do night and around-the-clock firefighters’ shift schedules induce deviation in tau from 24 hours of systolic and diastolic blood pressure circadian rhythms?
  Alain E. Reinberg, Michael H. Smolensky, Marc Riedel, Cedric Riedel, Eric Brousse, Yvan Touitou
  Chronobiology International.2017; 34(8): 1158.     CrossRef
• Ambulatory heart rate of professional taxi drivers while driving without their typical psychosocial work stressors: a pilot study
  BongKyoo Choi, SangJun Choi, JeeYeon Jeong, JiWon Lee, Shi Shu, Nu Yu, SangBaek Ko, Yifang Zhu
  Annals of Occupational and Environmental Medicine.2016;[Epub]     CrossRef
• Globalization, Work, and Cardiovascular Disease
  Peter L. Schnall, Marnie Dobson, Paul Landsbergis
  International Journal of Health Services.2016; 46(4): 656.     CrossRef
• 24‐hour work shifts, sedentary work, and obesity in male firefighters
  BongKyoo Choi, Marnie Dobson, Peter Schnall, Javier Garcia‐Rivas
  American Journal of Industrial Medicine.2016; 59(6): 486.     CrossRef
• Factors related to heart rate variability among firefighters
  Jae-Hong Shin, Jung-Youb Lee, Seon-Hee Yang, Mi-Young Lee, In-Sung Chung
  Annals of Occupational and Environmental Medicine.2016;[Epub]     CrossRef
• Twenty-four-hour work shifts, increased job demands, and elevated blood pressure in professional firefighters
  BongKyoo Choi, Peter Schnall, Marnie Dobson
  International Archives of Occupational and Environmental Health.2016; 89(7): 1111.     CrossRef
• Effects of high occupational physical activity, aging, and exercise on heart rate variability among male workers
  Dongmug Kang, Youngki Kim, Jongeun Kim, Yongsik Hwang, Byungmann Cho, Taekjong Hong, Byungmok Sung, Yonghwan Lee
  Annals of Occupational and Environmental Medicine.2015;[Epub]     CrossRef
• Factors associated with health-related quality of life in Korean older workers
  Sujin Hong, Harin Jeong, Yunjeong Heo, Hosun Chun, Jongtae Park, Daeseong Kim
  Annals of Occupational and Environmental Medicine.2015;[Epub]     CrossRef
• Non-Accidental Health Impacts of Wildfire Smoke
  Hassani Youssouf, Catherine Liousse, Laurent Roblou, Eric-Michel Assamoi, Raimo Salonen, Cara Maesano, Soutrik Banerjee, Isabella Annesi-Maesano
  International Journal of Environmental Research and Public Health.2014; 11(11): 11772.     CrossRef