The Science Of Sleep: What We Know And What To Track

It’s all very well to think you need more sleep. It’s another thing entirely to understand what’s happening to your body when sleep quality and/or quantity is insufficient.?

In a?recent post on the subject of sleep?we explored how much sleep you should be getting, and we considered how people might go about improving their sleep. In this post we dig a little deeper into the science of sleep and examine what you can learn from biomarkers related to sleep.?

There are a range of biomarkers that can be tracked when investigating potential problems with sleep. These include inflammation markers, cortisol, Intercellular Adhesion Molecule 1 (ICAM-1), and Interleukin-6 (IL-6), as well as hormones, Leptin, Sex hormone-binding globulin (SHBG), Testosterone and the immune cell secretion, Tumor Necrosis Factor alpha (TNF-alpha). Individually and collectively, these biomarkers can provide insight into the causes of sleep disturbance and can help provide guidance about how best to address imbalance.

For instance, an imbalance of inflammation markers may indicate that sleep is being affected by stress, disease, or by pain from chronic inflammation conditions. Alternatively, an imbalance of hormone biomarkers may point to issues with diet or could be indicative of menopause or other hormonal changes.?

Australian sleep professional, Olivia Arezzolo, has noted that tracking the biomarker, Cortisol, can provide useful information about what may be affecting sleep. “Cortisol is a stress hormone associated with fight-or-flight syndrome,” she says. “It makes you restless, alert and awake. High levels of Cortisol in your system are associated with poor sleep, so if your Cortisol levels are consistently high, then you might find that you wake up a lot around 3am”.

According to CEO of the Sleep Foundation, Moira Junge, sleep should be managed holistically. “While paying attention to some aspects of our health shows good results, that’s not necessarily going to be true for sleep,” she said. “Going to the gym and working out every day for a couple of hours will generate results. But rather cruelly, paying too much attention to sleep can actually exacerbate a sleep problem. So people are better off focusing on their overall health, and then sleep is more likely to fall into place.”

Dr Junge says the science of sleep has progressed substantially in recent years, but we still don’t have a specific test that can identify our sleepiness. “It would be great if we could get to the equivalent of a breathalyzer test,” she said, “But we are not there yet.”

“What we do know is that toxins build up in our brain daily, and these are cleared overnight in sleep. There was some research in the UK which was reported on incorrectly, saying that young people who don’t get enough sleep effectively have signs of dementia. And that’s just not true,” Dr Junge warned. “What does happen is that beta amyloid build-up happens to everyone, every day. And in the research, young people who were sleep deprived had a build-up of beta amyloid that was similar to that which occurs in people with Alzheimer’s Disease. But the difference is that when young people then subsequently get some sleep, the build-up is cleared and the system is reset.”

Dr Junge noted that other advances in the science of sleep relate to ocular movement and Melatonin levels. “We know now that there is a clear correlation between involuntary ocular movement and likeliness to fall asleep. So if you blink more often, your body is showing signs of fatigue and becoming more prepared for sleep,” she said.?

She also noted that Melatonin tests can be used to gauge sleep-readiness. “We know that there is a dip in core temperature and a rise in Melatonin levels just before sleep. And we can now perform saliva, blood and urine tests to determine whether our bodies are ready for sleep. However these tests are not readily available, they are very time consuming and only done in a lab setting, so often the result is that they can be expensive.”

Olivia Arezzolo says that Cortisol and Melatonin work together, so if Cortisol levels are high it may impact Melatonin levels. She says that one thing people can do to help reduce Cortisol levels in the body may be to reduce blue light exposure. “This is the kind of light we get from our phones, laptops and other devices,” she explained. “Blue light is known to stimulate Cortisol and reduce Melatonin levels. Limiting access to things that stimulate Cortisol in the body may be a good start. Try turning off all your devices for two hours before bed, and see what happens,” she suggested.?

Dr Junge believes that from a biomarker perspective, the key is to track overall health. Extensive research has demonstrated that?aerobic and resistance exercise?can improve sleep quality and reduce the risk of sleep problems. And good overall health, and low-to-moderate consumption of substances like alcohol and caffeine can greatly improve sleep health. “Healthy, fresh food and exercise are likely to have a positive impact on many factors that can influence sleep,” she said.?

Arezzolo adds that the herb, Ashwagandha (Indian ginseng), may also be considered as a way to mediate stress and Cortisol levels. “We all go through stressful periods,” says Arezzolo, “so consuming an adaptogen like Ashwagandha can help improve resilience to stress - and when you can improve stress resilience, you can preserve sleep quality even in stressful situations.”

Overall we need to make room for sleep in our lives, believes Dr Junge. “Having at least 2 hours to unwind before sleep is really important.” But, she warns, people who are night owls and morning people are quite different in the hour at which their melatonin levels rise, and up to 15% of teenagers need to stay awake a lot later at night and sleep in longer in the mornings. So the times that family members need to go to bed will be different, and respecting differences in family bed times should become routine.?

In particular, parents shouldn’t feel obliged to be the last people awake in the house. Instead, a routine of closing the door at night and respecting others’ need for quiet should be modeled. “Space for sleep should be provided in families, and modeled like brushing your teeth. If kids know that parents are prioritising sleep in order to help with their health and workload, they will begin to respect that and perhaps even pass it down to their children. It's a good routine that kids will get used to,” she said.?

Both Arezzolo and Junge believe that biomarkers are useful in tracking overall health.?

Dr Junge recommends “to make the most of morning exercise,” she said. “That gives you more energy and alertness and it suppresses your melatonin. And with morning exercise you build your sleep pressure over the following 16 hours.” What might be interesting is tracking the impact of morning exercise over time, and considering the impact of this on sleep patterns.

Arezzolo believes that tracking biomarkers like Cortisol over time can help you understand quantifiably the effects of different behaviours and diet on these biomarkers. “That helps you get a better picture of what might be contributing to your wellbeing, including your sleep patterns,” she said. “And these quantifiable, evidentiary changes over time will help you understand what works best for you.”

In the end though, anything that can improve sleep hygiene is worth pursuing, according to Dr Junge. “Sleep is such a precious commodity. We should do what we can to promote it in our lives.”