Byun, Kunjoon

Abstract Workplace stress is one of the main sources of stress for adults, although physiological and cognitive factors may impact each person's stress response. Numerous studies have shown heart rate, heart rate variability, neural activity, and cognitive performance are affected by stress. Additionally, visual and auditory stimuli in one's environment have been shown to affect individuals' reaction to stressful events. To our knowledge, few studies have examined how each of these physiological and cognitive measures relate to one's perception of stress, the ability to recover from stress, and what environmental factors may help with stress recovery. Here, 80 healthy adults performed a laboratory-controlled stress induction task where they experienced and recovered from an acute psychological stressor (Trier Social Stress Test, TSST, using verbal math skills and a public presentation that was videotaped). Throughout the assessment, heart rate, heart rate variability, and neural activity were measured using wearable devices to assess changes before, during, and after the stressor. Additionally, participants were assessed their perceived stress levels at specific times throughout the assessment. After the psychological stressor, participants were randomly assigned to one of four recovery conditions within a multisensory relaxation room: Control (C), Auditory Only (A), Visual Only (V), or Combined Auditory and Visual (AV). During the stressor, anxiety, heart rate, and beta EEG power increased and high-frequency power and heart rate variability decreased, confirming participants reactivity to the stressor ( P < 0.01 for all vs. baseline). Only the V and AV conditions led to notable reductions in anxiety (15 and 17%, respectively) vs. the C condition, but these did not reach statistical significance. There was no difference between V and AV, suggesting a stronger impact of V. We observed no differences between conditions during recovery for HR and HRV. Overall, these findings suggest the visual features of the relaxation room impacted self-reported anxiety, however physiological and neurological effects did not demonstrate a statistically meaningful response.

Previous work has demonstrated the modest impact of environmental interventions that manipulate lighting, sound, or temperature on sleep inertia symptoms. The current study sought to expand on previous work and measure the impact of a multimodal intervention that collectively manipulated light, sound, and ambient temperature on sleep inertia. Participants slept in the lab for four nights and were awoken each morning by either a traditional alarm clock or the multimodal intervention. Feelings of sleep inertia were measured each morning through Psychomotor Vigilance Test (PVT) assessments and ratings of sleepiness and mood at five time-points. While there was little overall impact of the intervention, the participant’s chronotype and the length of the lighting exposure on intervention mornings both influenced sleep inertia symptoms. Moderate evening types who received a shorter lighting exposure (≤15 min) demonstrated more lapses relative to the control condition, whereas intermediate types exhibited a better response speed and fewer lapses. Conversely, moderate evening types who experienced a longer light exposure (>15 min) during the intervention exhibited fewer false alarms over time. The results suggest that the length of the environmental intervention may play a role in mitigating feelings of sleep inertia, particularly for groups who might exhibit stronger feelings of sleep inertia, including evening types.

Abstract Introduction Sleep inertia is a temporary period of reduced alertness and impaired physical and cognitive performance that immediately follows waking. Sleep inertia can have devastating consequences necessitating an intervention to successfully mitigate symptoms. Previous work has demonstrated modest benefits for individual environmental interventions which manipulate either lighting, sound, or temperature. The current study sought to expand on previous work and measure the impact of a multimodal intervention that collectively manipulated light, sound, and ambient temperature on vigilance, mood, and sleepiness. Methods 37 adults (M=27.13 years, 19 F) who self-reported taking longer than 30 minutes to wake up for 60% of their work week slept in the lab for four nights. They were woken up each morning with either a traditional alarm sound or the multimodal intervention (two control nights and two intervention nights, counterbalanced across participants). Feelings of sleep inertia were measured each morning through completion of the Psychomotor Vigilance Test and ratings of sleepiness and mood at five different time-points (5, 15, 30, 60, and 90 min after wake). Results While there was little impact of the intervention on all outcome measures, there were differential impacts depending on a person’s chronotype and the length of the lighting exposure during the intervention condition. Moderate evening-types who received a shorter lighting exposure (£15 min) demonstrated more vigilance lapses (p = 0.04) relative to the control condition whereas intermediate-types demonstrated better response speed (p &lt; 0.005) and fewer lapses (p = 0.002). Conversely, moderate evening-types who experienced a longer light exposure (&gt;15 min) during the intervention exhibited fewer false alarms over time (p = 0.03). Participants who received a longer light exposure also reported marginally lower negative affect the longer they were awake (p = 0.06). Conclusion Collectively, the results suggest that the length of the environmental intervention may play a role in mitigating feelings of sleep inertia, particularly for groups who may exhibit stronger feelings of sleep inertia including evening-types. Results may help inform the efficacy of “smart alarms” that activate based on entering light sleep. Future studies should measure this impact using additional measures of cognitive performance. Support (If Any)