How to improve your sleep

Sleep science, the circadian rhythm, and research-proven success tips

Last week’s article was all about sleep physiology. I discussed in detail the regions of the brain associated with sleep, and how the sleep cycle works.

While doing my research, I came across the two-process model. It is an excellent physiological model explaining the two main sleep controllers. I find this very interesting because it explains why jet lag is so difficult to adjust to, and why I sleep better when I have been active all day or had a good workout!

I am often jealous of the people who can exercise command over their sleep. They lie down, shut their eyes, and within minutes they are fast asleep. I, on the other hand, struggle with sleep. I need my own familiar space, I need to do my mini sleep routine most nights, and I must have complete darkness and no noise!

I listened to a podcast very recently on sleep. It discussed how it is important not to try and control sleep, but to let go, and welcome whatever is in store for that night, restful sleep or not.

Although I agree that the notion of control over the act of sleep is silly, I feel there are things we can do during the day and at night to make our experience better. The science behind that is extremely interesting and vast. In no way is the following article comprehensive, but it does provide a peek into some of the factors controlling sleep!

Why you should read ahead

In this article, we are going to learn about:

• The circadian rhythm.

• The science behind exercise and its benefit on sleep.

• The relationship between stress, the environment, benzodiazepines, and sleep

Finally, I end this article with a special section on HOW to implement all you have learnt about sleep in your daily life to truly improve your sleep quality.

The two-process model

This model was proposed way back in the 1980s. It suggests that there are two main factors controlling sleep initiation and the wakeful state:

1.        Circadian rhythm

2.        Adenosine concentration (homeostasis mechanism).

The circadian rhythm

The circadian rhythm (CR) is the 24-hour clock in our body that primarily promotes alertness and sleepiness. Evolution has developed this sleep/wake cycle in our body to optimise the consumption of energy based on Earth’s rotation around its axis.

The CR is important for sleep desire. Ever felt sleepy at your usual sleeping time, but struggled to fall asleep before it? Or, even worse, have you ever woken up at your usual waking time even though you wanted to sleep in?

The CR controls this and although many factors influence it, one of the most important is light stimulus from the retina.

Light enters our eyes and hits the retina. This sends a signal to a nucleus in the brain called the suprachiasmatic nucleus (SCN) which sits very close to the hypothalamus. If you remember from the previous article, the hypothalamus is the anatomical region of the brain that controls sleep. The SCN is also known as the circadian rhythm pacemaker!

The light stimuli reaching the SCN then regulate the sleep or waking state of a person. More light entering the eye stimulates the SCN to promote wakefulness! (Some are immune to this and I'm jealous).

Melatonin is another CR factor you may have heard of. Melatonin is secreted from the pineal gland based on the amount of light entering the eye and is at higher concentrations in the body at night but reduces in the morning. That’s why melatonin tablets taken at night help people fall asleep.

To explain in further detail- let’s imagine a case scenario:

I left my curtains open and at 06:00 bright light starts to stream through my window.

This light hits my retina which sends a signal via a nerve called the Optic nerve to the SCN. Imagine the SCN to be a giant bear that doesn’t like its sleep disturbed. So, when it is disturbed, it sends out a giant roar of inhibitory impulses that inhibit the function of things around it.

One structure that it inhibits is the pineal gland. This impulse inhibits my pineal gland and stops the secretion of melatonin. The level of melatonin in my brain drops, consequently decreasing its concentration which wakes me up!

Homeostasis mechanism

The second of this two-process model is known as the homeostasis mechanism. I don’t understand why it’s called the homeostasis mechanism but if someone who is reading this does know why- please share.

I do know that it has everything to do with adenosine.

ATP is the energy currency of the cell. We have all read this in our biology textbooks! My non-medical friends used to love to chant “Mitochondria is the powerhouse of the cell” but that’s not what we are talking about here. ATP stands for Adenosine Tri Phosphate.

Whenever we walk, run, talk, eat, think, or do any activity- ATP is broken down to generate Adenosine as a by-product. Adenosine accumulates throughout the day and is concentrated in a region of the brain called the basal forebrain. Once adenosine is at a high concentration, it can block all the wake-promoting regions of the brain and initiate sleep. This is why on days that we have performed a lot of physical or mental activity, we fall asleep faster and feel as though the sleep was more restful!

How many of you have experienced great sleep after exercise?

Other Factors that may influence our sleep

Of course, sleep isn’t as simple as the two-process model. There are loads of other factors that influence it! I have an interesting list of those below. Some of this knowledge might help you understand how to improve your sleep patterns!

GABA neurons

Have you heard of GABA neurons? They are receptors present in large numbers in the brain which, when stimulated, send out proteins which cause relaxation, decrease in activity, and sleepiness. GABA neurons are the ones that are stimulated in NREM sleep which helps to deepen the sleep in an individual. It is these neurons that are stimulated when a person consumes Benzodiazepines (like Xanax or other sleeping pills). I found it quite interesting to note that the same physiological neurons that deepen sleep can be stimulated artificially! Naturally, the sleep doesn’t feel like the same as proper sleep. Also, disclaimer, please be careful with these pills. The side effects and potential to overdose are dangerous!

Stress

Sleep reactivity is:

The degree to which a person’s daily life and stresses impact their sleep.

According to the Journal of Sleep Research, individuals with highly reactive sleep systems find it difficult to fall asleep or stay asleep when exposed to a lot of stress. Not everyone has a high sleep reactivity. Some are able to sleep soundly despite a lot of stress, while others can’t!

The research on this is inconsistent. The problem with studying the association between stressors, like burn-out or bereavement, and sleep is that there are many confounding factors. Each person is different, and picking a cohort in which everyone is the same is quite difficult!

Nevertheless, multiple studies have found that emotional stressors, like a big fight with a family member, can impact slow-wave sleep. If you remember, slow-wave sleep is the type of sleep that occurs in the deepest level or N3! Worker sleep patterns were studied in detail, and it was found that those who suffer from burnout tend to have a high amount of sleep arousal during the night.

A strange and slightly mean study was conducted in the 1970s. Researchers exposed the cohort to emotional stressors like a terrible film right before bedtime. They were able to prove that these stressors can increase sleep latency (time taken to fall asleep) and worsen the quality of sleep with multiple arousals.

I have experienced this multiple times! Just the other night, I was reading the initial chapter of the Mahabharat which discusses Janameyaja and his Snake Sacrifice. Lo and Behold, I dreamt of slithering snakes which were coming after me and awoke at an uncomfortable 5 am!

I would love to hear your story. When was the last time stress impacted your sleep?

The environment

Bonnet and Arand, two sleep researchers published a paper in the Oxford academic journal in 2003. Their research wanted to investigate something called situational insomnia.

Have you ever found it difficult to sleep well in a new environment? The researchers wanted to study this in a standardised environment and used data from what is known as ‘Polysomnography’.

Polysomnography is a long word for the process of studying the sleep of an individual. Here, the subject’s head is connected to electrodes to read their brain waves, and their breathing and heart rate are measured.  Do you think you would be able to sleep well on the first night in a room such as this, with all sorts of wires connected to you? I wouldn’t!

Bonnet and Arand used this data to prove that those who don’t sleep well on the first night during polysomnography, suffer from situational insomnia. They are the type of people who can’t sleep in new environments very easily.

They also experimented with mini triggers like 400mgs of coffee a few hours before sleep or changing the sleep schedule to 3 hours before usual bedtime. Those who suffer from situational insomnia are also highly reactive to these mini triggers, compared to the other group who don’t struggle with sleep!

When I read this study, I felt a lot better knowing that there is a large group of people who struggle with sleeping in new environments, who absolutely can’t drink coffee before bedtime, and who can’t adjust to new sleep timings.

How to get the best sleep you have ever had

Finally, with all the knowledge above, let’s talk about how to implement that knowledge in your life.

I struggled with sleep. It hit a high point during my final years in medical school, probably because my academic and personal stressors were high. I was able to identify tactics that seemed to have worked. I stick to these principles of sleep even today.