NCT04514354

The Influence of Cardiorespiratory Fitness on Firefighter Cardiovascular Health Under Exercise Conditions

The Influence of Cardiorespiratory Fitness on Firefighter Cardiovascular Health Under Conditions of Heavy Physical Exertion

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 21 (actual)
• Sponsor: University of Connecticut · Academic / Other
• Sex: All
• Age: 21 Years
• Healthy volunteers: Not accepted

Summary

Sudden cardiac death (SCD) is the number one cause of on-duty firefighter death. It is most likely to occur in adults who are not physically fit that engage in sudden vigorous exercise. Cardiorespiratory physical fitness (also known as aerobic fitness) is a major heart disease risk factor. In FIT and FIRED UP, the study investigators looked at the influence of cardiorespiratory fitness on blood pressure, heart rate, and other heart markers taken from the blood before and after a vigorous exercise test to maximal effort among firefighters from a local fire department in Connecticut. In addition, the investigators also looked at how lifestyle habits including physical activity, nutrition, stress, and sleep may influence our findings. It was hypothesized that aerobically fit firefighters would show less stress on their heart than unfit firefighters.

Detailed description

The primary purpose of this study was to examine the influence of cardiorespiratory fitness on the acute release of SCD biomarkers and other cardiovascular disease (CVD) risk factors at rest and in response to a bout of maximal physical exertion among 21 firefighters from a local fire department in Connecticut. The study investigators hypothesized that firefighters that are aerobically fit will have lower levels of biomarkers of SCD and a more favorable CVD risk factor profile at rest and in response to a maximal physical effort than firefighters that are not aerobically fit. FIT and FIRED UP is based on the theoretical foundation of the health belief and social cognitive models of health behavior change which have been shown effective in improving diet and exercise behaviors in firefighters. Specifically, the investigators sought to identify job-specific risk factors for SCD and CVD in firefighters in order to better tailor an intervention that focuses on providing information, reducing barriers to changing unhealthy behaviors, reducing stress, and increasing firefighter efficacy to engage in healthier behaviors. All eligible members of the fire department were invited to participate in the study. Visit 1 included an orientation health education session at the fire department in which the study investigators delivered a lecture on physical activity and "heart healthy" habits. Interested subjects were able to review the informed consent and questionnaires. Subjects completed and signed the informed consent at the beginning of Visit 2. This visit consisted of 4 health-related fitness assessments, including sit-up, push-up, flexibility and handgrip tests. Visits 3 and 4 consisted of measures of cardiovascular health at Hartford Hospital and the control visit. The cardiovascular health measures included body mass index (BMI), waist circumference, exhaled carbon monoxide (CO), vascular health (i.e., carotid intimal medial thickness and arterial stiffness), heart rate variability (HRV), resting BP, the maximum graded cardiopulmonary exercise stress test (GEST), and blood draws pre- and post-GEST to obtain SCD and CVD biomarkers. Firefighters were then attached to an ambulatory blood pressure (ABP) monitor and heart rate monitor for 24hr to assess ambulatory BP and HRV, respectively. Of note is that Visits 3 and 4 were conducted in random order so that study investigators could isolate the influence of the GEST on the ambulatory BP response to exercise from the control rest day. Randomization was performed using www.randomization.com. The control visit included measures of resting and ambulatory BP. In addition, subjects completed paper and pencil questionnaires on the topics of physical activity, nutrition, sleep, and mental health at this visit.

Conditions

• Cardiovascular Diseases
• Post-Exercise Hypotension

Interventions

Type	Name	Description
BEHAVIORAL	GEST	On either Visit 3 or 4, subjects performed a maximal cardiopulmonary GEST following the Balke protocol. Immediately prior to the GEST, the study physician or his designee performed a brief physical examination, in which BP was assessed and all relevant medical information (i.e. medical history, medications, family history) were reviewed. The physician who completed the physical examination remained present during the GEST to monitor the subjects' electrocardiogram (ECG) and other physical signs. After the GEST was completed, the study physician reviewed the ECG for signs of ischemia. Breath-by-breath analysis of expired gases (i.e. oxygen and carbon dioxide) (ParvoMedicsTruneOne® 2400 Metabolic Measurement System, ParvoMedics Inc., Sandy, UT) determined maximal oxygen uptake (VO2max). Heart rate was measured continuously with a 12-lead ECG system and BP was measured by auscultation every 3 minutes during the GEST.

Timeline

• Start date: 2015-04-01
• Primary completion: 2016-01-01
• Completion: 2016-01-01
• First posted: 2020-08-14
• Last updated: 2020-08-14

Locations

1 site across 1 country: United States