Sleep patterns and physiological markers of stress in graduate paramedics

\\({Introduction / Aims}\\) New graduates are entering the paramedic workforce in Victoria in unprecedented numbers, undertaking shift work patterns that are known to be a risk factor for a raft of major medical conditions. Whilst most research in the healthcare field examines hospital-based staff, limited research is available that examines new recruits within the emergency medical response field and how they adapt to shift work. This study has assessed graduate paramedics during the initial five months of rotational shift work, aiming to identify if the quality and quantity of sleep is altered during this period of rotational shift work and if early risk factors of cardiovascular disease and metabolic disorders manifest during this initial exposure to shift work. \\({Methods}\\) Graduate paramedics commencing employment with Ambulance Victoria were assessed over a 25-day block before starting shift work (Baseline), and during their 1st and 5th month of shift work. In each block, sleep and activity level was recorded 24-hours a day using a wrist-worn actigraph device. Subjects also maintained a sleep log each morning and completed regular subjective sleep questionnaires. From this, Sleep duration - the number of hours/minutes scored as 'asleep' - was established. Sleep Efficiency was calculated as a percentage of time spent asleep from the time spent in bed. The number of awakenings (NoA) and the Wake After Sleep Onset (WASO) for each sleep period were recorded as an indication of sleep quality. Total sleep time (TST) for the 25-day period was also tallied and recorded in hours and minutes for each assessment. Data was compared across each assessment period using the 25-day average, during shift work and during RDOs. Further assessments of general health and well-being, including height, weight, waist circumference, resting heart rate, blood pressure, fasting blood glucose, body composition, aerobic fitness (step test), and subjective stress questionnaires were also conducted at the commencement of the Baseline period, at the conclusion of shift work Month 1, and pre- and post- shift work Month 5. \\({Results}\\) 28 participants (13 male and 15 female) completed the full study protocol. A significant (p =0.046) increase in the total sleep time was observed across the 25-days of each month when shift work was undertaken. The number of sleep episodes recorded during these months of shift work also increased (p <0.005), however sleep efficiency did not differ significantly (p =0.17). The NoA recorded for the sleep episode after night duty was significantly less in Month 1 (p <0.005) and Month 5 (p <0.01) compared to Baseline. All sleep metrics recorded during RDOs were not different to Baseline with the exception of the night before returning to work, where there was a significant reduction in sleep duration (p <0.005). During shift work, self-reported poor sleep quality increased compared to Baseline (p <0.001). A significant (p =0.0097) increase in the percentage of time spent sedentary was observed across the study protocol, coinciding with a significant (p =0.0026) decline in the percentage of time spent undertaking light exercise, but not moderate to vigorous physical activity (MVPA) nor the average number of steps recorded per day. No significant difference was observed in participants' weight (p =0.071), however waist circumference did increase significantly (p =0.008). No significant changes were noted for systolic (p =0.33) or diastolic (p =0.98) blood pressure, nor fasting blood glucose levels (p =0.64). \\({Discussion}\\) The 25-day mean Sleep Efficiency remained the same throughout each assessment period, as did the RDO Sleep Efficiency recorded during the shift work phases of the protocol. Alterations in sleep patterns, necessitated by the rotational roster structure, influenced the 25-day mean data for WASO and NoA. However, when looking specifically at RDOs, there was no difference in measures of sleep disturbance compared to Baseline. A shorter Sleep Duration consistently observed on the final RDO suggests that paramedics are not well-rested for their first day back at work. Overall sleep quantity increased during Month 1 and Month 5 of shift work, however sleep became more fragmented leading to an increased number of short duration sleep episodes. Short sleep has well established links to major medical conditions including diabetes, obesity, heart disease and Alzheimer's disease. Data showed increased amount of sedentary time, reduction in light exercise and increased waist circumference. This may indicate that early risk factors for major medical conditions are presenting in the first six months of ambulance work. \\({Conclusion}\\) This study is the first quantifiable research to assess physiological changes in sleep patterns and activity levels of graduate paramedics undertaking a new career with shift work. The data suggests that shift work leads to more fragmented sleep patterns. What is not clear is the consequences on job performance and the long-term implications for paramedics' health. Subsequent research involving larger cohorts over longer time frames is needed to assess if alterations to sleep patterns persist over a paramedic's career or even beyond their ambulance service employment.