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• Bouts of light-intensity walking may improve speed maintenance ability. • Drivers may favour lane maintenance over speed maintenance during driving. • Crash likelihood does not decrease after breaking up sitting during the day. • Breaking up sitting during the day does not decrease subjective sleepiness when sleep is restricted. Sleep restriction and prolonged sitting are both associated with reduced cognitive performance which is detrimental to safe driving. Regular bouts of walking to break up prolonged sitting have been shown to improve cognitive performance. It is unknown if breaking up sitting with walking may improve cognitive performance related to driving, particularly when drivers are sleep restricted. Healthy participants (n = 81, age 23.6 ± 4.5 years, 49% female) participated in a 7-day laboratory study (1 Adaptation day, 5 Experimental days, 1 Recovery day). Participants were randomly allocated to a condition: sitting 9 h sleep (Sit9), breaking up sitting 9 h sleep (Break9), sitting 5 h sleep (Sit5) and breaking up sitting 5 h sleep (Break5). Participants allocated to the Break9 and Break5 conditions completed 3-min of light-intensity walking on a treadmill every 30 min between 09:00–17:00 h, while participants in Sit9 and Sit5 groups remained seated during these times. Each participant completed a 20-min monotonous simulated driving commute at 08:10 h and 17:30 h on each of the 5 Experimental days. There was a significant main effect of condition with decreased speed variability for Break9 compared to Sit9, Sit5 and Break5 (p < 0.0001) for both commutes. Break5 had significantly higher lane variability compared to Sit9 and Break9, and Sit5 (p = <0.05) for both commutes. Break5 reported greater subjective sleepiness before each commute compared to Sit9, Break9 and Sit5 (p < 0.001). Cox Proportional Hazards model showed a significant increase in time to first crash for Sit5 and Break5 compared to Sit9 (p= <0.005). There were no significant two- or three-way interaction effects by condition, day or commute time for any of the outcome measures. The findings from this study highlight that breaking up sitting with light-intensity walking may improve driving performance in areas such as speed maintenance, but may not extend to lane keeping performance. The findings also show that the benefits of breaking up sitting with light-intensity walking may not be sufficient to overcome detrimental impacts of sleep restriction for all areas of driving performance. Future research should focus on increased intensity of activity as a possible means to extend the benefits more comprehensively across additional areas of driving performance. [ABSTRACT FROM AUTHOR]

• Breaking up sitting during the day may reduce calibration errors in subjective assessments of driving performance for key areas of performance. • Drivers were poorly calibrated for the areas of speed maintenance regardless of prior sleep history and levels of physical activity during the day. • Drivers with 9 h of lower had lower levels of subjective workload compared to drivers with 5 h of sleep. • Single component and 3-componenet Brier score provided a holistic approach to exploring subjective assessments of driving performance. Self-assessed driving ability may differ from actual driving performance, leading to poor calibration (i.e., differences between self-assessed driving ability and actual performance), increased risk of accidents and unsafe driving behaviour. Factors such as sleep restriction and sedentary behaviour can impact driver workload, which influences driver calibration. This study aims to investigate how sleep restriction and prolonged sitting impact driver workload and driver calibration to identify strategies that can lead to safer and better calibrated drivers. Participants (n = 84, mean age = 23.5 ± 4.8, 49 % female) undertook a 7-day laboratory study and were randomly allocated to a condition: sitting 9-h sleep opportunity (Sit9), breaking up sitting 9-h sleep opportunity (Break9), sitting 5-h sleep opportunity (Sit5) and breaking up sitting 5-h sleep opportunity (Break5). Break9 and Break5 conditions completed 3-min of light-intensity walking on a treadmill every 30 min between 09:00–17:00 h, while participants in Sit9 and Sit5 conditions remained seated. Each participant completed a 20-min simulated commute in the morning and afternoon each day and completed subjective assessments of driving ability and perceived workload before and after each commute. Objective driving performance was assessed using a driving simulator measuring speed and lane performance metrics. Driver calibration was analysed using a single component and 3-component Brier Score. Correlational matrices were conducted as an exploratory analysis to understand the strength and direction of the relationship between subjective and objective driving outcomes. Analyses revealed participants in Sit9 and Break9 were significantly better calibrated for lane variability, lane position and safe zone-lane parameters at both time points (p < 0.0001) compared to Sit5 and Break5. Break5 participants were better calibrated for safe zone-speed and combined safe zone parameters (p < 0.0001) and speed variability at both time points (p = 0.005) compared to all other conditions. Analyses revealed lower perceived workload scores at both time points for Sit9 and Break9 participants compared to Sit5 and Break5 (p = <0.001). Breaking up sitting during the day may reduce calibration errors compared to sitting during the day for speed keeping parameters. Future studies should investigate if different physical activity frequency and intensity can reduce calibration errors, and better align a driver's self-assessment with their actual performance. [ABSTRACT FROM AUTHOR]

New mothers generally experience poor and/or disrupted sleep. A range of infant care and mental health factors may impact new mothers' sleep quality. A cross-sectional online survey was completed by a sample of 101 Australian new mothers with children under 12 months (M = 5.52 months, SD = 3.29 months) to examine the relationship between infant feeding method, infant sleeping location, and postpartum depression with maternal sleep quality. Subjective maternal sleep quality was measured using the Pittsburgh Sleep Quality Index (PSQI), and postpartum depression was measured using the Edinburgh Postpartum Depression Scale (EPDS). Overall, new mothers experienced poor subjective sleep quality, with high average PSQI scores, above the cut-off of 5 (M = 9.63, SD = 4.07). The majority of new mothers did not experience postpartum depression, with an average EPDS score below the cut-off of 11 (8.66, SD = 5.20). Mothers who breastfed their infants experienced significantly better subjective sleep quality than mothers who bottle-fed, with a medium effect size (ηp2 = 0.458). Subjective maternal sleep quality did not differ based on infant sleeping location. Poor subjective maternal sleep quality was a significant predictor of postpartum depression. While poor sleep was common in this sample of Australian new mothers, this study demonstrated that new mothers who breastfeed may experience slightly better subjective sleep quality than other feeding methods. Further research into, and better services for the education and advocation of, new mothers' sleep quality will be beneficial to both new mothers and clinicians. • New mothers typically experience poor and/or disrupted sleep. • Their sleep can be impacted by personal factors and factors relating to infant care. • Breastfeeding was associated with better maternal sleep quality. • Maternal sleep quality was associated with infant sleeping location. • Poor maternal sleep quality predicted postpartum depression. [ABSTRACT FROM AUTHOR]

• >50% of new mothers who regularly drove did so while fatigued at least a few times each month. • 8.4% of new mothers reported having a near miss while driving every month. • New mothers should be categorised as an at-risk group for fatigued driving. During the first year of their child's life, mothers typically experience disrupted sleep and high levels of daytime fatigue. Other populations who experience sleep disruption and/or fatigue are considered to be at risk for fatigued driving. However, the degree of fatigue-related risk experienced by new mothers in Australia is unclear. This study aimed to investigate the prevalence of fatigued driving, fatigue-related near misses, and vehicle crashes in this population. A cross-sectional survey including the Pittsburgh Sleep Quality Index and a range of fatigue and driving questions was completed by 187 Australian new mothers. Over 50% of participants who regularly drove did so while fatigued at least a few times per month. Furthermore, most participants who reported near misses indicated that either some or more than some of these incidents were attributable to fatigue (>70%). Similarly, >55% of participants who reported experiencing a motor vehicle crash since the birth of their child indicated that this crash was caused by fatigue. These findings suggest that new mothers may be considered an at-risk group for fatigued driving. To address this issue, it may be appropriate to provide education around driver safety, and to establish strategies to help minimise fatigue-related driving risk in this population. Furthermore, future research should include objectively measured sleep to establish the link more accurately between prior sleep and driver safety in new mothers in Australia. [ABSTRACT FROM AUTHOR]

• New parents are likely to experience sleep loss due to childcare responsibilities. • A systematic review was performed to understand the relationship between sleep and driver fatigue in new parents. • Synthesis of available evidence suggests that new parents are at risk of fatigued driving. • A research agenda is proposed to address the limitations of this field of research. Fatigue-related motor vehicle crashes are common worldwide and have been addressed by a range of road safety campaigns. These campaigns are typically directed towards at-risk groups (e.g., heavy vehicle drivers), who may be likely to experience fatigue resulting from reduced or disrupted sleep opportunities. Another population likely to experience sleep loss and disruption is new parents. The sleep of new parents is likely to be significantly disrupted by childcare responsibilities. As such, new parents may also be likely to experience fatigue while driving. A systematic review of five databases (PubMed, Cumulative Index to Nursing and Allied Health Literature, PsycINFO, EMBASE, and the Cochrane Central Register of Controlled Trials) was performed to identify what research is currently available on sleep, fatigue, and driving in new parents. A total of twelve documents were included in this review. A synthesis of findings suggests new parents are at risk of fatigued driving – though the amount and quality of evidence available is limited. A research agenda is proposed to address the limitations of this field of research. [ABSTRACT FROM AUTHOR]