I used to sleep notoriously little. I was known as a low mean, high variance kind of sleeper.

This semester I took a class by Dr. Matthew Walker - The Psychology of Sleep - it gave me the impetus to make a very substantial change to my sleep habits. I am now a high mean, low variance sleeper. This reorientation in outlook towards sleep has left me feeling healthier, happier and much more productive.

I originally opted for Psych 133 because I wanted to be able to game the system with the things that I would learn. I thought that I would be able to leverage my newfound knowledge to become a biphasic sleeper who would utilize naps to get by with the bare minimum amount of sleep humanly possible. By the end of the second midterm I was trying to plan my day around my 7.5 hour minimum. This was a function of the research that we were shown and my reflections with regard to that research.

Over the course of my first complete blog post ( 🎉 ), I am going to share the bits and pieces of the course that impacted me the most. Correspondingly, I am going to share the definitive changes that I made to my lifestyle (I really did).

A cursory search of my text messages (Spelling errors and subtle roasts included) will reveal my progress. This is in addition to the countless remarks that I have received in person.

Note: I am going to abstract away many terms/concepts in order to maintain a low level of complexity within this post. As a result, this will only serve as a 10,000 foot overview of certain parts of the course (not a comprehensive review).

Health and Immune Functioning

Did you ever notice how we tend to sleep a lot more than usual when we are ill? There is a fairly strong association between sleep habits and health/immune response.

When researchers immunized two groups of individuals after 4 days of observation, they noticed a discrepancy between the immune response of the two groups. The control group was allowed to sleep normally prior to the immunization. The second (deprivation) group was restricted to 4 hours of sleep per night for the 4 days prior to the immunization. The antibody response of the deprivation group was less than half as strong as the control group. This difference persisted even after a very substantial amount of recovery sleep. Therefore, the amount you sleep can very directly impact how susceptible you are to falling sick/rebounding from sickness.

To further examine this phenomenon we were told about an experiment wherein researchers tracked the average amount that subjects slept over the course of 7 days. Subsequently, the subjects were administered nasal drops containing Rhinovirus and were monitored for symptoms of a cold over a period of 5 days. Independent of antibody levels, demographics or other such factors: subjects who slept less were more likely to be susceptible to illness.

Over the course of the class, we were told about nuanced associations which illustrated a strong link between sleep deprivation and cancer. Apparently, a 4 hour reduction in sleep corresponds to a 70% reduction in Natural Killer Cells compared to normal. Such a decline is associated with a higher risk of developing cancer. Furthermore, the World Health Organization actually classifies shift work and chronic circadian-disrupters as “probable carcinogens”.

We were also shown studies which highlighted links between sleep deprivation and Type 2 diabetes (impairments in the glucose metabolism) and obesity (alterations in hormones which regulate hunger).

This was the first portion of the course that drew my attention towards how little I sleep. It was the first red flag that I needed to start sleeping more than my 4.5/6 hour stints. Unfortunately, “once-removed” and highly deferred effects are not great at catalyzing overwhelming change. It certainly made me more cognizant of my decisions to stay up late and hang out with friends/wrap up work, however, it seldom made me reconsider.

Memory and Performance

There is a very conspicuous difference in my clarity of thought and my ability to navigate steep learning curves depending on the amount of sleep that I am operating on. I was not aware of the scale of the effects and the long term ramifications of depriving oneself of the recommended amount of sleep ( $\geq$ 8 hours).

A very interesting phenomenon that was illustrated in class was the discrepancy between the subjective and objective measures of attention and alertness. In turns out that humans are not great at subjectively assessing their sleepiness. Take a look at the figure below:

If you look at SD 7 (the 7th night of sleep deprivation) you will notice that the groups which were constrained to 7 hours per night for 7 days and 9 hours per night for 7 days perceived the same level of sleepiness in a self assessment. When the same groups were objectively assessed via a Psychomotor Vigilance Task (PVT) there were some discrepancies in their levels of performance. Notice how the number of attention lapses measured by the test tends to diverge for two groups over time? It was really interesting to me how the 7 hour group tends towards the 5 hour group over the course of the seven days.

This can also be seen in the figure below which illustrates the deterioration in attention through time (due to the lack of sleep). The manner in which the negative effects of partial sleep deprivation compounded through time was very alarming to me. Notice how the performance of the group which slept 6 hours per night was much closer to the one which slept 4 hours per night than it was to the group which slept 8 hours per night.

Beyond the above, there was a plethora of evidence presented to us about how different sorts of memory are positively enhanced by varying combinations of sleep. Other compelling studies showed that skill based memories (motor and visual skills) are enhanced and consolidated by sleep. Also, we saw that the early stages of sleep help build immunity against forgetting and contribute to “stabilizing” fact based memories. Additionally, we were shown studies which established how sleep helps in the integration of knowledge, in extracting commonalities and building associations, and helps in building abstractions which provide intuition about problems.

To me this was a more immediate and impactful set of outcomes. I put this to the test by enforcing a 7.5 hour minimum and I saw results almost instantly. I was able to focus better, I felt that my understanding of subjects improved, and saw a slight uptick in my willingness to jump into complex problems.

The corrective measures

A big part of maintaining this 7.5 hour minimum was integrating complementary lifestyle changes into my routine. I built a framework which would coerce me into sleeping 7.5 hours or more. The following are three habits that helped me adhere to my new sleep schedule:

• Exercising closer to bed time: I started working out from 9 - 10 PM this semester. This makes me feel very tired by around 1 AM and I knock out almost instantly. When I climb into my bed (sans laptop) I am asleep within 3 or 4 minutes consistently. My quality of sleep has also increased as a result. Exercising also makes it unsustainable to sleep less than 6 hours because my body starts to shut down because of exhaustion.

• Napping! Sometimes sacrificing an hour or two of sleep cannot be avoided. When I am faced with such situations I found it easier to not fall into a tailspin and I try to maintain my routine by napping in the afternoon. Over the course of the class we learnt that this sort of behavior is not entirely unprecedented and that napping in the afternoon has many upsides for memory and learning.

• Stopped drinking Caffeine: This is another important thing that we learnt in the class - coffee gives us a very artificial sense of energy by masking the signal of certain hormones. It also decreases deep sleep. I realized that it is better (long term) to not consume coffee and plan my day in a more effective manner. This semester I have culled my coffee consumption in its entirety.

Instituting this structure on my sleep schedule has given me impetus to initiate changes in other areas of my life which I had been neglecting: eating healthier and exercising more (as mentioned above). I have also started to develop a general preference for structure and organization over ad hoc plans (this is probably stems from my efforts to preserve my 7.5 of sleep every night). Overall it has been one of the more impactful lifestyle changes that I have adopted and for this reason I wanted to share the context surrounding my decision with others as well.

What next?

This report was a part of my final project for the class. One aspect of evaluation was outreach - sharing lessons from the class with others. The responses to this post + a draft of this post have been fairly consistent: where can I learn more about sleep? To that end I would recommend the book Why We Sleep by Dr. Matthew Walker. It is a great book and runs almost in parallel with the ideas that we discussed in Psychology 133 this semester. It is a great resource to raise your level of awareness about one of the most ubiquitous and fundmental biological needs of every human: sleep.