A bad night's sleep can leave you waking up drained. But unlike a phone, your energy doesn't necessarily keep falling throughout the day. In workplace research, people often report a rise in energy during the morning, a peak around midday, and a decline later.

Dr. Oliver Weigelt, assistant professor of organizational psychology at the University of Groningen, joins Neil Hedley to discuss what sleep quality changes about our starting point, the effort paradox, why afternoon fatigue is more complicated than it seems, and where shift work fits—or doesn't fit—into the evidence.

This observational study followed 106 employees across up to 10 workdays; its group-level patterns are not universal recommendations or sleep treatments.

Research: Handschuch, Weigelt and colleagues, Journal of Business and Psychology (2026). Guest: Dr. Oliver Weigelt, University of Groningen.

British Columbia stopped changing its clocks on November 1, 2026. But there's a catch: ending the twice-yearly switch and choosing which time to keep are two different questions.

In this episode, Neil Hedley talks with Dr. Ralph Mistlberger, a professor of psychology and circadian-rhythm researcher at Simon Fraser University, about why he believes permanent standard time is better aligned with our biology than permanent daylight time. Mistlberger is a co-author of a new Canadian Medical Association Journal analysis examining the potential health, education and economic trade-offs of these policies.

They explore how morning light resets the human body clock, why darker winter mornings may worsen the mismatch between biological time and school or work schedules, and what researchers mean by social jet lag. Their discussion also considers the political appeal of brighter evenings—and why popularity doesn't necessarily answer the biological question.

Most importantly, the conversation distinguishes between the disruption of changing clocks twice a year and the consequences of living on a particular time year-round. The CMAJ paper reviews evidence and identifies risks; it does not establish that every person will experience the same effects.

Further reading: Lam RW, Mistlberger R, Baylis P, Choi A. Analysis of health impacts associated with adopting permanent standard time or permanent daylight saving time to inform policy in Canada, CMAJ (October 2026). B.C. government's announcement of permanent Pacific Time (UTC−7). Dr. Mistlberger's SFU profile.

What does a sleep tracker actually measure when it tells you that you slept badly—and how much should you trust the score?

Stanford sleep and circadian researcher Dr. Jamie Zeitzer joins Neil Hedley to unpack the gap between a precise-looking number and the evidence behind it. They discuss why wrist-based devices can estimate sleep duration reasonably well for some people yet struggle when sleep is fragmented, what proprietary sleep scores leave unexplained, and why a single night's rating may be less useful than patterns over time.

Neil shares how wearable data prompted him to seek a formal sleep assessment. They also explore what a more useful future could look like: changes that prompt better questions for a clinician, links between daytime behavior and nighttime sleep, and feedback about a bedroom environment that could be adjusted.

Important distinction: Consumer sleep trackers estimate aspects of sleep; a sleep score is not a medical diagnosis. The future applications discussed are possibilities, not established benefits of every device.

Further reading: Jamie M. Zeitzer, The utility of sleep wearables—well, that depends, SLEEP (2024), read the editorial. Zeitzer, A time for change: actigraphy in the age of consumer wearables, SLEEP (2026), read the editorial. Dr. Zeitzer's Stanford profile.

Could the same brain structure be associated with better sleep in some young people and worse sleep in others?

Dr. Aaron Mattfeld of Florida International University joins Neil Hedley to discuss research on the pineal gland, anxiety, and objectively measured sleep in early adolescence. The gland is involved in melatonin production, but the study found that the relationship between pineal-gland tissue volume and sleep varied with anxiety severity.

They explore why the result was surprising, what researchers can and cannot conclude from it, and how adolescent biology and everyday choices affect sleep.

About the evidence: This is an observational association, not proof that pineal gland size causes sleep problems. Melatonin production was not directly measured.

Research: Fuertes F., Lalama M., Dick A. S. et al., Anxiety severity moderates the relation between pineal parenchymal volume and objective sleep problems in peri-adolescent youth, Scientific Reports (2026). Read the study.

Florida International University's research overview · Dr. Mattfeld's faculty profile · The Snooze Button.

Next week: Dr. Jamie Zeitzer on what your sleep tracker can—and cannot—tell you.

Could the lighting in your home or workplace be interfering with your sleep?

Chronobiologist Dr. Marijke Gordijn joins Neil Hedley to explore how light influences our biological clocks, why blue light isn't necessarily the enemy, and how changing our everyday lighting habits could improve our sleep.

Gordijn is the founder and director of Chrono@Work, a guest researcher at the University of Groningen, and a co-founder of the Good Light Group.

In this episode, we explore:

• The biological clock: What circadian rhythms actually are, and how our bodies keep track of time.
• The 500-lux problem: Why ordinary indoor lighting may be insufficient during the day.
• Blue light: Why we need it during the day but should limit it as bedtime approaches.
• Shift work: The challenges of working while our biological clocks are telling us to sleep.
• Power naps: Why even a short period of rest may improve alertness.
• Night owls and creativity: Whether our individual biological rhythms influence when we perform our best.
• Melatonin: Why timing and dosage matter, and why it isn't necessarily a solution to poor sleep quality.
• Practical changes: How daylight exposure, evening lighting and screen habits can help support healthy circadian rhythms.

Guest

Dr. Marijke Gordijn

Chronobiologist, Founder and Director of Chrono@Work, Guest Researcher at the University of Groningen, and Co-founder of the Good Light Group.

Resources

Chrono@Work — Dr. Gordijn's research organization

Good Light Group — Practical guidance on healthy lighting

University of Groningen — Marijke Gordijn's research profile

2022 Scientific Consensus: Recommendations for Daytime, Evening and Nighttime Light Exposure

• Why Brian and his colleagues expected sleepy employees to “punch down” in the workplace
• The surprising result that conflict was strongest with higher-ranking people
• Why the U.S. Army provided an especially interesting environment for studying hierarchy
• What workplace conflict actually looked like in the research
• Neil’s highly scientific description of the problem as a failing “BS filter”
• Why self-control may help explain the connection between sleep and conflict
• How poor sleep can affect anger, risk-taking and rule-breaking as well as interpersonal conflict
• Why recognizing a bad night’s sleep may help you manage the following workday differently
• How chronotype and time of day can compound the effects of poor sleep
• Sleep, workplace injuries and the danger of simply blaming the employee
• Why organizations themselves can contribute to employees’ sleep problems
• The idea of sleep leadership
• Whether managers should be asking employees how they slept
• Why unpredictable work schedules can be particularly disruptive
• Shift work and the importance of regularity when regular daytime schedules aren’t possible
• Whether the same sleep-and-hierarchy dynamic might show up between parents and children
• What happens when both the employee and the boss are sleeping badly
• Whether poor-sleep conflict could cascade upward through an organization
• Why Brian wants to see the findings tested outside the military and in flatter organizations
• What employers can reasonably take away from this research — and what this single study cannot establish

Dr. Brian Gunia is Professor and Area Chair for Management & Organization at the Johns Hopkins Carey Business School.

His research examines negotiation, organizational behavior and sleep, with particular interest in the ways insufficient sleep can influence decision-making and behaviour in the workplace.

His work has explored topics including sleep and self-control, leadership, ethics, negotiation and interpersonal conflict.

Before entering academia, Brian worked as a management consultant. He earned his PhD in Management & Organization from Northwestern University.

Sleep and Strife: The Effects of Sleep on Conflict within Organizational Hierarchy

Brian Gunia, Paul Bliese and Amy Adler examined the relationship between sleep problems and interpersonal conflict inside organizational hierarchies. Their research found that sleep problems were most strongly associated with conflict involving people of higher rank — the opposite of what the researchers initially expected.

Brian Gunia — Johns Hopkins Carey Business School

Faculty profile, research interests and selected publications.

In this episode:

• Why Jade Wu had just woken from a nap before the interview
• Why she thinks of naps as snacks
• What happens when trying to make sleep happen becomes the problem
• Why Wu wrote Hello Sleep
• The access problem surrounding Cognitive Behavioral Therapy for Insomnia
• Who CBT-I is actually for — and what it does not treat
• Why an overnight sleep study is not routinely necessary for uncomplicated insomnia
• Neil's periodic limb movements and the case for treating comorbid sleep problems together
• What happened when a sleep psychologist became a severely sleep-deprived new parent
• Sleep disruption, postpartum depression and the danger of single-cause explanations
• Why sleep can be foundational without being the explanation for everything
• How sleep optimization and sleep trackers can create pressure
• Why melatonin is a timekeeping hormone rather than a sedative
• The label-accuracy problem in commercial melatonin products
• When melatonin may have legitimate circadian uses
• Why chronotype can collide with school and work schedules
• How social media and streaming services compete with sleep
• Why daytime light changes the brain's sensitivity to evening light
• What the evidence does — and does not — say about screens and blue-light blocking
• Mindfulness without turning mindfulness into another performance task

Dr. Jade Wu, PhD, DBSM, is a board-certified sleep psychologist, researcher and author of Hello Sleep: The Science and Art of Overcoming Insomnia Without Medications. Duke University currently lists her as an Associate in Research whose work focuses on treating sleep disorders in people with chronic illness. Her own site describes her broader work in behavioral sleep medicine, public education and her company Thrive; it also lists her as a Clinical Assistant Professor at SUNY Upstate Medical University and says she will join Cornell University's Psychology Department faculty in Fall 2026.

Wu earned her undergraduate degree at Cornell, her PhD at Boston University, and completed medical psychology residency and clinical fellowship training at Duke University School of Medicine.

• Hello Sleep: The Science and Art of Overcoming Insomnia Without Medications — Jade Wu
• Jade Wu — Duke Department of Neurology
• Dr. Jade Wu
• AASM guideline: behavioral and psychological treatments for chronic insomnia
• 2025 systematic review: CBT for adult insomnia in routine clinical care
• AASM practice parameters: evaluation of chronic insomnia and use of polysomnography
• 2017 study: melatonin content variability and serotonin in commercial supplements
• 2023 study: melatonin and CBD quantities in U.S. melatonin gummies
• Health Canada: melatonin as a natural health product
• AASM pharmacologic guideline: melatonin and chronic insomnia
• The human circadian system adapts to prior photic history
• 2024 National Sleep Foundation consensus statement on screens and sleep
• 2025 systematic review and meta-analysis of blue-light blocking glasses and objective sleep
• The Many Challenges of Insomnia — Dr. Jade Wu
• Sex & Sleep: Was It Good For You?