Mathias Basner is an assistant professor of sleep and chronobiology in psychiatry at the University of Pennsylvania's Perelman School of Medicine, and the deputy editor of the journal SLEEP. In answer to my questions, he shared his insights on the effects of sleep deprivation, the relationship between work and sleep, and the small steps anyone can take to improve their sleep immediately.
Describe your research on the effects of sleep loss on neurobehavioral and cognitive functions.
We perform both experimental laboratory studies and observational field studies. In the laboratory studies we sleep-deprive subjects (e.g., one night without sleep, or multiple nights with, for example, only four hours of sleep opportunity) and observe how their behavior, physiology and metabolism changes. We are obviously interested in the question "How much sleep do you need?" but also in the questions "How fast do you recover?" and "What happens if you get re-exposed to sleep deprivation after a short recovery (e.g., after a weekend with sufficient sleep)?"
Our observational studies are mainly funded by NASA and the FAA. We currently investigate the effects of aircraft noise on sleep around Philadelphia airport. We have also developed brief cognitive tests for astronauts and are currently investigating how cognitive performance changes during spaceflight. We have already investigated 24 astronauts during six-month missions on the International space Station with the so-called Psychomotor Vigilance Test. This test is based on simple reaction time and is very sensitive to sleep loss. We also investigated how astronaut performance is affected by sleep medications if they are woken up due to an emergency.
Finally, we have analyzed data on large population-based time use surveys.
You have done population studies on sleep time and waking activities. What have you found?
Our research overwhelmingly showed that time spent working was the most prominent sleep thief. It was evident across all sociodemographic strata and no matter how we approached the question.
Short sleepers started working earlier in the morning and stopped working later at night. With every hour that work or educational activities started later in the morning, sleep time increased by approximately 20 minutes. Those working multiple jobs were 61-percent more likely to be short sleepers. Moreover, self-employed respondents with more flexible work times were less likely to be short sleepers on weekdays, and average sleep time was higher during the economic crisis years with lower employment rates.
The findings also point to behaviors unrelated to work that are associated with short sleep. Common culprits appeared to include watching TV late at night or spending prolonged periods of time in the bathroom grooming each morning. In these areas, the researchers say, raising awareness about the importance of sufficient sleep for health and safety may be necessary to reduce the prevalence of short sleep.
Do you have a bedtime routine that helps you transition into sleep mode? What are a few tips you would give to someone looking to improve their sleep right now?
This is typically subsumed under the topic "sleep hygiene." Some of the tips are:
- Only use your bedroom for sleep and sex. Entering the bedroom should be a signal for your body that it is time to retire. Importantly, keep the television out of your bedroom.
- A light- and noise-free environment is important for undisturbed sleep. If your house is facing a busy road, try to move your bedroom to the back of the house. Closing the windows and shades may help keep the light and noise out, but make sure to vent the bedroom properly before retiring.
- Bright-light exposure immediately before going to bed suppresses melatonin secretion, and melatonin helps us fall asleep. Turn off the lights in the bathroom and instead use the light from the hallway while grooming before bed. Bathroom mirror lights can be excessively bright and thus suppress melatonin excretion. Also, turn the light down during the late evening, and try not to expose yourself to bright light from the TV, e-readers, etc., late at night.
- No excessive food or alcohol intake or exercise in the hours pre-bed.
What tangible improvements would a later start to the workday bring?
Our research suggests that for every hour work (and school) starts later in the morning, sleep time increases by circa 20 min. Also, we found that self-employed respondents were less likely to be short sleepers, probably due to the greater flexibility in their timing of work. Therefore, postponing work and school start times, or making them more flexible, could potentially increase sleep time. However, the supporting evidence is still scarce, and more intervention studies are needed.