WHY DID YOU CHOOSE TO SPECIALISE ON THE TOPIC OF SLEEP AND HOW IT IMPACTS US?
I like to think of myself as a sleep diplomat. In graduate school, I joined a lab that was focused on stress and the immune system. We created a number of paradigms designed to stress people out while sampling their blood. We did a lot of studies on how T Cells (a key part of our adaptive immune system) respond when people experience stress. Discovering that their ability to divide is actually diminished under acute stress.
If you deprive people of sleep, then measure their blood the next day and compare this to when they sleep normally, you see very similar negative impacts on their immune system. When people have more stress in their life it makes it harder to fall, and stay asleep because our mind is really active. Conversely, when people don’t get the sleep they need, it’s really hard to go through the world and deal with the regular stressors. Suddenly little things seem like big things.
This dynamic actually provides a lot of hope, because it means there are two opportunities for intervention. We can target someone’s stress and try to demonstrate that it has some spillover effects on their sleep. This helps them with their sleep by reducing the amount of stress or giving them more coping resources. We can’t control all the stressors that go on around us, but we can certainly improve the way we relate to those things. Sleep seems to be the secret sauce that helps people do that. So I got really into it and have just continued down that line.
HOW WOULD YOU DESCRIBE THE RELATIONSHIP BETWEEN SLEEP AND STRESS?
I think in some way we always knew that this relationship existed, but over the last five years or so we have really tried to understand where the strength of those relationships lie. Some of this is done by tracking how people behave by utilising wearables and giving people a diary on their phone that they fill out multiple times a day. This asks them if something stressful happened, and if so how they responded? This is then paired with the data obtained from wearables such as galvanic skin response and heart rate variability, offering physiological signatures of these changes and experiences.
There have been several studies on this topic that indicate the strength of this relationship centres around the duration of sleep. When people get less sleep than they typically do they become more reactive to minor hassles in their life. Sleep is so fundamental to our biology, we have regulators of sleep, and we have a routine of things that we do each night. There are lots of environmental cues to regulate our sleep system.
When dealing with people with insomnia we often find that these environmental cues are part of the problem. Patients will tell us that they feel sleepy before going to bed, and then when it gets closer to bedtime they start to feel anxious and their brain becomes really active. What tends to happen in these cases is they build up what’s called a ‘conditioned response’. You spend enough time feeling bad in a place that when you go to that place you just start to feel bad automatically. Your body sends a signal to your brain saying what’s supposed to happen. For most people who don’t have insomnia, it works the other way around. Getting into bed creates a really strong response, telling your brain that this is a safe place to check out and go to sleep.
SO, A BAD NIGHT’S SLEEP STRONGLY IMPACTS OUR ABILITY TO COPE WITH STRESS THE FOLLOWING DAY MORE THAN A STRESSFUL DAY IMPACTS OUR ABILITY TO GET A GOOD NIGHT’S SLEEP?
It’s a little more nuanced than that. Common stressors that we all live with usually won’t have a big impact on our sleep. But when people are experiencing chronic levels of stress then that’s certainly going to impact their sleep. What we’re also finding is that our way of relating to stressors seems to make a difference. We did a study where we manipulated the experience of stress close to bedtime in people’s homes. We set up this paradigm where people thought they were involved with other people in the study. But it was really us, and we made them feel cut out of the programme. What we found is that making people feel left out is really stressful, and this was so activating that they ended up getting less sleep.
When we looked at the data more carefully, it was really about whether people already had a tendency to ruminate about things. For people who already had a tendency to get in their head, and play things over and over and over this was really powerful. This is where stress management and mindfulness-based therapies can help us regulate our brains under these conditions.
WHAT DO YOUR STUDIES INDICATE IN REGARDS TO THE IMPACT OF SLEEP ON OUR IMMUNE SYSTEM – PARTICULARLY OUR RESPONSE TO VACCINES?
There is by now a fairly consistent set of studies that show that if we deprive people of sleep, typically for one to two nights, just after getting a vaccine then this can have a modest effect on their ability to mount a response. The good news about those studies is that people do seem to catch up – their antibodies were just slowed in response. We found that when people got six or fewer hours, for each additional hour that they got, we saw an increase of around 52% in antibodies. For the hepatitis B vaccine, maybe six months after when they started the initial vaccination series, people who slept six or fewer hours, were around ten times more likely to be left in the unproductive protected category, compared to people who slept for eight or more hours.
We’ve seen similar associations with influenza, where people who slept less, were mounting fewer antibodies to one of the strains, which is important because it could have policy implications. If it turns out that sleep is important then it would be worthwhile to let people know that if they are going to get their vaccine to get a good night’s sleep, to increase the efficacy.
When we talk about stress and our stress response, and how we can recharge our bodies and minds in order to better deal with stress, it’s like our secret superpower. This is the ultimate way of charging our bodies as well as our minds.
WHAT WOULD BE YOUR TOP THREE TIPS FOR SOMEONE STRUGGLING WITH INSOMNIA?
First off I think it’s important to say that everyone is going to have nights where they have a bad night’s sleep, and that’s completely natural. Evolutionarily we are designed to maintain
alert in periods of stress. However, if this goes on night after night then it really starts to degrade our well being, so it’s important to know how to get things back on track.
The two primary regulators of our sleep are what’s called our homeostatic sleep drive and our circadian rhythm. Circadian rhythm is key here because this tells our body what to do and trains our rhythms. So when that rhythm is off things don’t seem to work as well for us. So when people are having sleep problems I always suggest that they set their wake up time to be consistent seven days a week. This may sound hard as many of us love sleeping in on the weekends, but if you normally wake up at six, and then you wake up at eight, that’s like your body being in two different time zones.
The other thing that’s really critical is spending time in bed, not sleeping. This is something that people get into a habit with, and it’s fine if you don’t have a sleep problem. If you have a sleep problem, however, you don’t want to get in bed until you’re sleepy as we don’t want you in bed awake, degrading this relationship with your bed.
The third thing that I think everyone can do is protecting your wind-down period. People often think I’ll just get the work done tonight and spread it out. That’s a problem, where it’s so often the case that sleep is the thing that people do when everything else is done, but they don’t appreciate the importance of this wind-down period. Work is done, close the laptop, turn off the phone, and allow yourself to transition. People often do this far too late in the evening where they think I’ll turn this off and go straight to sleep. We’re not computers, you can’t just shut the laptop of your brain in the same way. Around two hours before you want to try to go to bed just do things that bring you joy and relaxation. Doing so will reap the benefits of improved productivity, cognition, sharpness and your ability to multitask.
Dr Aric Prather is a Professor of Psychiatry and Behavioral Sciences at the University of California, San Francisco and author of “The Sleep Prescription”. He conducts research around stress, sleep, how the two are related to each other, and the impacts on our body, our immune system and our ability to cope with stress when we don’t get enough sleep.