Sleep Expert Jamie Zeitzer, PhD, Seeks the Truth

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By Sharon Brock, MEd, MS

Like a Renaissance explorer, the insatiable curiosity of Jamie Zeitzer, PhD, drives him to explore big questions as a senior researcher and co-director of the Stanford Center for Sleep and Circadian Sciences. After 25 years of conducting sleep research, including groundbreaking studies on circadian rhythms and how light affects the brain, Dr. Zeitzer still enjoys navigating the uncertain waters of research and helping us all get a better night’s sleep.

“What drives me in research is the fact that I don’t like uncertainty and I don’t like being wrong, and I picked a profession where I’m literally wrong all the time,” says Dr. Zeitzer, Professor (Research) of Psychiatry and Behavioral Sciences.

“Usually, the most obvious path in research is based on incomplete information, and it ends up not being true. So, we ask, what can we learn from this? How can we reformulate this question in a way to disprove this theory and try again? As a researcher, I’m consistently wrong but because I hate being wrong, I’m driven to get to the bottom of these big questions and seek the truth with a capital T,” says Dr. Zeitzer.

How Much Sleep Do We Need?

Since millions of Americans struggle with disordered sleep, Dr. Zeitzer is constantly fielding questions as a public health ambassador. However, it’s often difficult for him to give a straight answer because a) he doesn’t want to be wrong, and b) there’s a lot of grey area when it comes to sleep research.

For example, the number of hours of sleep we need for good health is different for everyone. For some, six hours of sleep is sufficient while others need more than nine. To assess how much sleep someone needs, Dr. Zeitzer recommends monitoring how sleepy they feel during the day without skewing the results with caffeine.

“If I get pressed, I say, ‘Most people need seven hours per night’,” says Dr. Zeitzer, “but, since many of us caffeinate away our sleepiness, we aren’t making the accurate self-assessment about how much sleep we really need.”

Other factors that affect sleep amount and quality are shift work, behavior choices, household or family obligations (i.e. having infants or teens in the house) or having anxiety about sleep.

“If you’re a bad sleeper, I say, ‘Don’t worry about it,’ because worrying about it just makes it worse. Now you have inadequate sleep and anxiety,” says Dr. Zeitzer. “With consistent bad sleep, yes, there is a slight increased risk of diabetes, Alzheimer’s, injury or poor cognition down the line, but the thing that’s really going to kill you is anxiety. So, if we first reduce anxiety about sleep, then we can work in a positive way about getting better sleep.”

Current Research

Even though millions of Americans struggle with sleep, others, such as many teens and 20-somethings, don’t prioritize sleep because they’d rather stay awake. Since there is delayed gratification related to the benefits of good sleep, many young people would prefer to stay out late with their friends or engage with technology into the night. Given the dopamine reward from receiving “likes” on social media or the stimulation of computer games, it’s more enjoyable for teens to stay awake on their phones rather than going to sleep.

“Growing up on Long Island in the 80s, I watched Star Trek every night, but by midnight, there was nothing on TV, so I went to sleep,” says Dr. Zeitzer. “But now, you can watch Netflix or play computer games all night because entertainment is optimized to never stop watching.”

Dr. Zeitzer is currently the father of three teenagers, so although he is working on several research projects, the one he is most excited about examines the sleep patterns of teens. He explains that two major factors are causing teens to go to sleep later—puberty causes the circadian system to shift to a later hour and entertainment is designed to make it more enjoyable to stay awake.

To address the circadian system so that teens feel sleepy at an earlier time, the research team uses lights that flash on a timer and shift the teenage brain into a different time zone. As a psychological intervention to promote behavior change, researchers also created videos with sleep information tailored for teens.

“We wanted the videos to be relatable and entertaining, so we came up with archetypes to represent three sleep patterns we find in teens,” says Dr. Zeitzer. “The night owl is named Otis, who doesn’t feel sleepy until 2:00 a.m. because of his circadian window. The mountain lion is Libby—she’s the alpha type who can’t turn her brain off. And the raccoon is named Rocky; he’s our gamer. Everyone loves Rocky—he plops on the couch after school, takes a nap, listens to EDM, then games all night.”

Educational Background

As an undergraduate, Dr. Zeitzer attended Vassar college in New York and received a diverse liberal arts education. Although he majored in biology, he took many English, philosophy, art, and medieval studies courses. He went on to attend Harvard University to earn a PhD in neurobiology and wrote his thesis on human circadian rhythms and how light impacts the circadian clock and regulates melatonin.

Dr. Zeitzer came to Stanford as a post-doc in 2001, achieved a faculty position in 2006, and has been running his own sleep lab for the past 18 years.

“I’ve been very fortunate that I’ve been able to explore a variety of scientific questions that I find intellectually compelling over the course of my career,” says Dr. Zeitzer. “I enjoy collaborating with other researchers who are experts in their field. My goal in science is not to have the highest-paid lab, but to get as close to the truth as possible—I would rather be close to the truth than anything else.”

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Screen Time and Sleep—It’s Different for Adults

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By Mary Grace Descourouez, MS, NBC-HWC and Sharon Brock, MEd, MS

Many of us have heard that looking at our phones or iPads at night can keep us awake due to light exposure, however, research shows this may be true for children, but there is not sufficient evidence to support this claim for adults.

“Young children have a greater sensitivity to light because more light gets to the retina of a child than an adult,” says Jamie Zeitzer, PhD, Co-Director of the Stanford Center for Sleep and Circadian Sciences. “Since adults have more opacities in their eyes and smaller pupils than children, less light passes through adult eyes, so there’s less of an effect on melatonin production.”

Melatonin is a hormone that makes us feel sleepy and is released when the eyes perceive darkness. Conversely, when we see natural light in the morning, we feel more awake because light hitting our eyes stops the production of melatonin.

Given this logic, it would seem reasonable that looking at our screens (smart phones, computers, iPads, etc.) at night could delay melatonin production and inhibit our ability to fall asleep, but Dr. Zeitzer says this is not the case.

While darkness enables melatonin production, suppressing melatonin production works by the brain comparing the amount of light we receive during at night with how much we received during the day. It’s the shift from light to dark that cues the release of melatonin, which is why we start to feel sleepy after the sun goes down.

Since natural sunlight emits 10,000-100,000 lux of light and phone screens emit 25-50 lux under usual conditions at night, Dr. Zeitzer says the light from our screens doesn’t have much of an impact on the melatonin cueing process.

“There just isn’t that much light coming from your phone,” says Dr. Zeitzer. “As long as you go outside during the day and get exposed to the intensity of natural light then the amount of light from a screen in the evening most likely won’t halt the production of melatonin.”

If it’s Not Light, What Keeps us Up at Night?

Rather than light exposure, Dr. Zeitzer believes that what is keeping us awake is what we are watching on our screens. Millions of Americans stay awake at night scrolling on social media looking at page after page of emotionally activating content and writing posts that lead to likes, comments, and followers. Others stay up to play games on their phones or computers, all of which stimulate the dopamine reward system in the brain, which is the basis of addictive behaviors.

“In the past, when a television show ended, you turned off the TV and went to sleep because there was nothing else to do,” says Dr. Zeitzer. “But now you could watch Netflix, look at apps or play computer games all night because this entertainment has been commodified to engaged with it for as long as possible; it’s optimized to never stop playing and this is causing sleep deprivation.”

When watching screens before bed, Dr. Zeitzer recommends that we not only avoid content that could be distressing, but also content that could stir excitement within us.

“In order to fall asleep, we need to reduce stimuli exposure and calm our mind and body,” says Dr. Zeitzer. “Even if you’re watching something positive, if it stirs excitement, the brain will release dopamine, and over time we can develop a dopamine addiction, making staying awake playing games or on social media much more fun that going to sleep.”

Lastly, Dr. Zeitzer says that he can’t make a general statement that nighttime screen use negatively affects everyone’s sleep. For some, their addiction to games or apps could make falling asleep a challenge, while others may watch soothing nature videos on their phones to help them relax and fall asleep. Therefore, Dr. Zeitzer suggests that you take note of how screens are impacting your sleep health by asking yourself these questions:

  • Is the content of your screen time making you feel distressed or excited? If yes, then you should not look at screens for about an hour before bedtime to calm the mind and body and prepare for sleep.
  • Also, do you engage with screens throughout the night when you could be sleeping? If so, you may have a dopamine addiction that is making screen time activities more enjoyable than sleep.
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insomnia

How to Cure Insomnia

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By Sharon Brock, MEd, MS

Not getting enough restorative sleep is a rampant health concern across the US. It’s estimated that 50 to 70 million Americans suffer from sleep disorders, and 1 in 3 adults do not get the recommended 7 to 8 hours of sleep regularly.

Many of us have tried sleep hygiene techniques, such as keeping our bedroom dark, cool, and quiet and having a one-hour-before-bed evening routine, but still have trouble sleeping soundly on a consistent basis.

Stanford sleep specialist Fiona Barwick, PhD, DBSM shares that sleep hygiene is only one piece of the puzzle.  “If you have good sleep and maintain good sleep hygiene, then you’ll continue to get good sleep,” says Dr. Barwick, Stanford Clinical Associate Professor, Psychiatry and Behavioral Sciences – Sleep Medicine. “But if you have poor sleep, all the sleep hygiene in the world will not help because it’s not targeting what we typically see in patients with insomnia, which is anxious thinking and not building enough sleep drive.”

What Causes Insomnia?

Insomnia is defined as difficulty falling asleep, staying asleep, or waking up too early (greater than 30 minutes before the alarm) three times per week for at least three months. Many factors can cause insomnia, such as stressors related to one’s job, finances, health, family and friends, new onset health conditions, or feeling unsafe in one’s environment.

Dr. Barwick says her patients with insomnia often spend hours lying awake, ruminating about relationships and events in their lives, or simply worrying about how their inability to sleep will impact their performance the next day (especially true for perfectionists). To address these factors, Dr. Barwick teaches classes on cognitive behavioral therapy for insomnia (CBT-I) at Stanford University.

“It’s a vicious cycle. The anxiety we feel about not sleeping can prevent us from falling and staying asleep,” says Dr. Barwick. “With CBT-I, we address not only the physical requirements of sleep but also how we think and feel about sleep. CBT-I helps to shift our mindset about sleep.”

 

This table shows the difference between sleep hygiene and CBT-I:

How to Cure Insomnia with CBT-I Training

CBT-I employs a classical conditioning technique of having patients get out of bed when not sleeping so that they associate their bed with sleep and nothing else. Just as Pavlovian dogs salivated when they heard a bell, Dr. Barwick says we can teach our brains to see our bed as a cue to feeling sleepy and falling asleep rather than a place where we lie awake feeling anxious.

Along with bed re-association, another technique for improving sleep is sleep consolidation, or shortening the time spent in bed. At the outset of treatment, students of the CBT-I course are instructed to reduce the amount of time they spend in bed (their “sleep opportunity”) and get out of bed promptly when the alarm goes off (no hitting snooze!), regardless of how they slept. As wakefulness at night decreases and sleep quality improves, time in bed, or sleep opportunity, is gradually extended.

This disciplined approach of spending a shorter amount of time in bed for two to three weeks increases sleep drive and thus sleepiness, or the desire to sleep. By the end of treatment, patients are falling asleep more easily, waking up less at night, and returning to sleep more easily. They have also ensured that their bed is re-associated with sleep, rather than lying awake worrying, thus breaking the pattern of insomnia.

Along with bed re-association, CBT-I also offers cognitive strategies to calm anxious thoughts about sleep, relaxation techniques to reduce tension in the body, as well as emotional relaxation practices like mindfulness.

How Do I Fix My Sleep Problems?

Ironically, anxiety about sleep is often the cause of our sleep problems, making stress management an important part of restorative sleep. Dr. Barwick says that “our mindset about sleep is critical. We are worrying about a system that is not broken.” Instead of anxiety about sleep, Dr. Barwick encourages us to learn about the biological systems involved in sleep and optimize them with our behaviors.

The three biological systems that need to be in working order for sleep to occur are:

  • Circadian rhythm
  • Sleep drive
  • Stress management

“The way sleep works is, when your sleep drive is high, you understand your own circadian sleep-wake timing, and you allow yourself to relax, you should fall asleep and return to sleep easily,” says Dr. Barwick. “These biological systems of sleep are not broken; they are intact, but our worry about sleep can override their ability to function properly.”

For practical tips on how to optimize these three systems, read our blog, “Don’t Hit Snooze! And Other Practical Tips for Optimal Sleep.” 

What to Do When Lying Awake in the Night

If you’re lying awake in bed during the night, the first step is not to check the time. This can lead to anxious thoughts about how your lack of sleep will affect you the next day. It’s best not to look at the clock and trust that you’ll wake up and get out of bed with your alarm.

Secondly, take deep breaths and engage in mindfulness practices, such as feeling the softness of your pillow and appreciating the comfort of your mattress. Listening to gentle music or a guided meditation can also help relax the mind and body.

If these relaxation practices do not lull you back to sleep and you’ve been wide awake for over 30 minutes, Dr. Barwick suggests getting out of bed and doing a relaxing activity in another room until you feel sleepy again.

“It’s best to keep your bed for sleep, so if you can’t fall back asleep, be awake outside your bed in an enjoyable and relaxing way, such as reading a book in the living room,” says Dr. Barwick. “While reading, you build sleep drive and calm anxiety, so you’re more likely to fall asleep when you go back to bed.”

Another thing to remember is that your middle-of-the-night thinking comes from your emotional brain. During sleep, the rational part of your brain is offline, leaving your emotions to run unchecked. This can lead to bizarre dreams and even nightmares that could wake you up, especially if you’re going through stressful circumstances.

To address this, Dr. Barwick recommends reducing stress throughout the day, not just right before bed.

“People with anxiety are more reactive to stress and need to address sleep as a 24-hour endeavor,” says Dr. Barwick. “They need to put more effort into managing their stress response with exercise, deep breaths, and mindfulness throughout the day–not just before bed.”

Dr. Barwick explains that when we first go to sleep, our sleep drive is high enough to counter our stress level. But if we wake up 3-4 hours later, when sleep drive has diminished, it is harder to fall back asleep, especially if our emotional brain begins to ruminate from stress built up throughout the day. And since the rational part of the brain is offline, these negative thoughts can take over our consciousness.

Therefore, Dr. Barwick recommends journaling before bed to reframe life challenges and process difficult emotions. This way, if you wake up at night, you’ll be able to fall back asleep easily.

Along with journaling before bed, Dr. Barwick has a second recommendation for those experiencing anger that often leads to the rehearsal of mental arguments during the night.

“If you have resentment, I recommend you do loving-kindness meditation before bed. You can offer loving-kindness toward those whom your ego believes has ‘wronged’ you,” says Dr. Barwick. “This meditation can shift your emotional mindset from anger to ease, which will help you fall asleep.”

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More Sunlight Exposure May Improve Sleep

What is our circadian rhythm?

Our circadian rhythm is our internal clock, keeping us on track for many of our day-to-day activities. When we go to sleep and when we wake up the following morning are the most common activities that people associate with our circadian rhythm, though there are many more things that it influences (metabolism, mental and physical performance, immunity, etc.). This sleep-wake cycle can be influenced by various stimuli throughout the day, but it is most heavily influenced by changes in light exposure. Light is considered the major “zeitgeber” or stimulus that helps our body to understand when to do certain activities like sleeping and waking. This means when we are exposed to light, especially bright light like sunlight, has a big effect on our sleep-wake pattern. 

Sunlight’s effect on circadian rhythm

“Many people today are working remotely or are in offices with little natural light exposure. Many of these same people may tend to struggle with sleeping at night and are unaware of how a few changes to their lifestyle may help them begin to improve their sleep. Finding lifestyle habits to prioritize early morning and daytime sun exposure can help to improve sleep later that night,” says Jamie Zeitzer, PhD, Stanford University Professor and member of the Stanford Lifestyle Medicine sleep team. 

Even going outside for 30 minutes can help. In the morning, sunlight helps to tell your circadian clock what time it is. In the afternoon, sunlight helps to make the clock stronger. At any time of day, getting sunlight means that the artificial light to which you are exposed at night will have less of an impact. Whether it is taking the dog out for a morning walk or finding time to bask in the sun over lunch, spending a little more time outdoors during the day can help regulate our internal clock and is the first step in a healthier relationship with sleep. It’s a win-win!

By: Carly Smith, BS, MPH(c)

Sources:

  1. Hoffmann et al. “Aerobic Physical Activity to Improve Memory and Executive Function in Sedentary Adults without Cognitive Impairment: A Systematic Review and Meta-analysis“. Journal of Preventative Medicine Reports. Sep. 2021.
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Aerobic & Resistance

Aerobic & Resistance Exercise Improves Sleep

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Sleep, a fundamental element of human biology, plays a crucial role in various physiological processes. A good night’s sleep is essential for immune function, cognitive performance, emotional well-being, and overall physical health. Exercise is another critical lifestyle factor with tremendous potential to improve your health. Regular physical activity has numerous benefits, from reducing the risk of chronic diseases to improving mental health. However, could exercise improve your sleep?

Impact of Resistance Exercise on Sleep

A 2017 review found that “chronic resistance exercise improves all aspects of sleep, with the greatest benefit for sleep quality” in individuals with sleep problems. In this study, Kovacevic et al. employed a systematic review methodology by conducting an electronic database search of randomized controlled trials. Many studies fit the criteria, but three acute resistance exercise studies, seven chronic resistance exercise studies, and three combined aerobic and resistance exercise studies met the researchers’ inclusion criteria and were analyzed for sleep outcomes. The primary finding from this review was improvements in sleep from chronic exercise; these improvements were “moderate-to-large, and commonly affected overall sleep quality, sleep latency, sleep efficiency, mid-sleep disturbance, and daytime dysfunction”. In comparison, the primary medications prescribed to improve sleep quality had “only small-to-moderate effects on sleep quality” and instead have “adverse effects such as rebound insomnia, depression and anxiety, cognitive impairment, and an increased risk of falls, cancer, and overall mortality” if used in the long-term. Kovacevic et al. call for further research and more data on aerobic exercise but cites an earlier paper that noted how aerobic exercise could improve sleep quality.

Furthermore, their work highlighted how “higher intensity and greater frequency of training offer greater sleep benefits”. More specifically, the chronic resistance exercises studied that had the most benefits included machine-based resistance exercise, circuit training, and resistance bands for an average duration of 14 weeks total with approximately 60 minutes per session. Studies with high exercise intensity as compared to low-to-moderate intensity, and with a frequency of 3 days/week as compared to 1-2 days/week, had a larger beneficial effect on sleep quality.

The review presented another pathway by which exercise could improve sleep; exercise improves levels of anxiety and depression, both of which deeply affect sleep — “notably, exercise has been shown to be an effective treatment for major depression and sleep disturbance is one of the core symptoms of depressive illness” and “the majority of chronic studies included in this review reported significant improvements in neuropsychological outcomes”.

Impact of Aerobic Exercise on Sleep

Additional research has also shown the further benefits of aerobic exercise for people with established sleep disorders. One study showcased how “4 months of aerobic exercise training in a sample of older adults with insomnia significantly improved sleep quality while also reducing daytime sleepiness and depressive symptoms”. Another study found that “12 weeks of moderate-intensity aerobic and resistance exercise resulted in a 25% reduction in OSA [obstructive sleep apnea] severity”. Lastly, studies have even shown that the circadian rhythms disrupted in neurodegenerative disease can be improved with exercise — “exercise has proven to be a low risk and beneficial intervention to improve overall health and sleep disorders in AD [Alzheimer’s disease] and PD [Parkinson’s Disease]”. In particular, “physical activity, even at low intensities, has been reported to improve sleep quality, reduce time to fall asleep, and increase the duration of sleep in the elderly… evidence indicates that exercise increases total sleep time and slow-wave sleep”.

We all strive for better sleep even if we do not have a known sleep disorder, and it could be within our grasp through a novel route. Exercising for an hour three times a week at high intensity with machine-based resistance exercise, circuit training, or resistance bands can improve your sleep quality and decrease issues in the day. Even once a week at a lesser intensity for 40 minutes showed beneficial effects! Sleep and exercise are significant pillars in lifestyle medicine, and it is fascinating how one affects the other. Rather than relying on medications that can have adverse effects, research suggest exercise is a natural way we can improve our sleep. While further research is needed, recognizing the interconnectedness of exercise and sleep as critical components of a healthy lifestyle is crucial.

By: Keshav Saigal, BS(c)

Sources:

  1. Kline, Christopher E. “The bidirectional relationship between exercise and sleep: Implications for exercise adherence and sleep improvement.” American Journal of Lifestyle Medicine. 2014 August
  2. Kline, Christopher E et al. “The effect of exercise training on obstructive sleep apnea and sleep quality: a randomized controlled trial.” Sleep. 2011 December
  3. Kovacevic, Ana et al. “The effect of resistance exercise on sleep: A systematic review of randomized controlled trials.” Sleep Medicine Reviews. 2018 June
  4. Memon, Adeel A et al. “Effects of exercise on sleep in neurodegenerative disease.” Neurobiology of Disease. 2020 July
  5. Reid, Kathryn J et al. “Aerobic exercise improves self-reported sleep and quality of life in older adults with insomnia.” Sleep Medicine. 2010 October
  6. Yang, Pei-Yu et al. “Exercise training improves sleep quality in middle-aged and older adults with sleep problems: a systematic review.” Journal of physiotherapy. 2012 September
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How Does Caffeine Affect You?

How Does Caffeine Affect You?

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It is difficult to predict how and for how long caffeine affects our bodies. Research suggests that caffeine affects everyone differently and our relationship with it could change as we age. A study examining the relationship between chronotype and the effects of caffeine on sleep in Stanford students found early birds had a strong correlation between daytime caffeine use and waking during sleep. Night owls’ sleep seemed to not be affected by their daytime caffeine intake. People in between seemed to experience minor effects. However, this study was exclusive to Stanford students, who are generally a more sleep-deprived population. It is unclear the degree to which this affected the results but is likely a significant confounding variable.

One of our sleep experts, Dr. Jaime Zeitzer, PhD, says , “There is massive variability in how people metabolize caffeine and in many, even a single cup of coffee with breakfast can interfere with sleep. Being aware of how your caffeine consumption personally impacts your sleep is incredibly important.”

By: Carly Mae Smith, BS

Sources:

  1. Modeling caffeine concentrations with the Stanford Caffeine Questionnaire: preliminary evidence for an interaction of chronotype with the effects of caffeine on sleep
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Healthy Lifestyle Habits Have Positive Effects on Mental Health

Healthy Lifestyle Habits Have Positive Effects on Mental Health

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This review article clearly highlights the importance of healthy lifestyle choices on mental health. Whole plant based diet and daily exercise have remarkable effects on our mood. In many studies, the effect has been described as equivalent to taking antidepressant medications. In addition, good sleep, daily gratitude, positive thoughts about the future, and being of service to others has also been shown to have lasting positive effects on our mental health.

By: Sarita Khemani, MD, Head, Lifestyle Medicine Stress Pillar

Journal Reference:

  1. Morton DP. Combining Lifestyle Medicine and Positive Psychology to Improve Mental Health and Emotional Well-being. Am J Lifestyle Med. 2018 Apr 18;12(5):370-374. doi: 10.1177/1559827618766482. PMID: 30283261; PMCID: PMC6146362.
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