The Science Of Waking Up Early: Why Early Morning Light Is Good For The Mind

There is a conventional wisdom in India that if one gets up early in the morning, in the hours considered as the hour of the Gods – the Brahma Muhurta, then the whole day goes well. Perhaps, some day, this conventional wisdom may get validation from some mice in a Swiss lab. It should be emphasized as a caveat that not every traditional wisdom needs validation from science.

A paper published by a team of researchers from the Department of Biology, University of Fribourg, Switzerland, in PLOS genetics simply states, ‘Light affects behavioral despair involving the clock gene Period 1’.

The winter in the West is severe. So much so that the decrease in light creates a psychological disorder called ‘Seasonal Affective Disorder’ (SAD). Administering ‘bright light therapy’ for the patients with recurring ‘SAD’ episodes has created positive results. A 2009 study noted that ‘bright light given well in advance of the emerging symptoms prevented a depressive episode.’

We humans share with mammals a region buried quite deep inside the brain that acts as a biological clock. This is called the 'suprachiasmatic nucleus' (SCN). It controls the daily rhythms of body temperature, pressure and also sleep. It is this SCN which communicates with the pineal gland to release melatonin which makes the person sleep and stop its release to make the person wake up.

Then there is an evolutionarily old region in our brain, called lateral habenula (abbreviated as LHb). This is the region in which neurons get activated when 'dementors surround a person'. In laboratory mice study, the region is related with depression-associated behaviour.

The gene associated with the body clock is called per1 gene. This gene expression is found in both SCN and LHb. The scientists aimed to study how the light exposures at different hours have the effect on the gene per1 – related to the circadian rhythm, particularly with respect to their expression in LHb.

In the experiment, the female mice were subjected to 12 hours of darkness in a 24-hour time cycle. They were also subjected to a series of tests used for measuring anxiety and depression in mice, like the forced-swim test, sucrose preference test etc. For example, consumption of sucrose with no work shows hedonistic consumption. With depression it is the opposite – a condition called anhedonia.

When the mice were exposed to light pulse at the onset of the dark period, it had no effect in elevating them from depressive behaviour resulting out of simulated SAD. The depressive behavioural patterns continued. Then the pulse of light was applied at the end of the dark 12-hours cycle – similar to the early morning hours. This light pulse clearly had an effect in reducing the depression-related behaviour of the mice significantly.

Thus, taking together the results of the study, the team puts forth the thesis that the amount of per1 gene expression in the SCN and the LHb correlate with despair-based behaviour. And early morning light pulse does affect the per1 gene expression in LHb. The ‘early morning’ mimicking light pulse resulted in increase per1 gene activity in LHb region which in turn decreased the depressive behaviour.

The complete switching off of the per1 gene resulted in no change in the behaviour of the mice irrespective of the time of employment of the light pulse. The early morning light pulse effect works in the mammalian animal irrespective of it being nocturnal or diurnal, opines one of the researchers in the communication to ‘The Scientist’ magazine.

As stated in the beginning, not every conventional wisdom has a scientific reasoning behind it and nor does it require a lab certificate. But given the kind of validation that unexpectedly and in unconnected ways, arises from the labs for some of our everyday customs, it is hard not to think why such researches do not take place in India.

India has a long tradition of Surya-Namakar- the early morning sun-salutation exercises to the sun. It combines spirituality and physical exercise in an organic manner. Yet, we do not have a proper study on the effect of this on our ability to cope with depression, a study particularly relevant in the Covid-19 lockdown times.

Approach to the inner universe in Hindu traditions can provide quite a lot of exploratory frameworks to studies like the above. For example, perhaps the tri-guna framework can be used to understand the above phenomenon: does the lateral habenula activity provide a neural correlate for tamas? Should the per1 expression, in counteracting the depression-causing activity of LHb, be understood as a gene-mediated neural correlate of sattva overcoming tamas? And how do traditional yoga and meditation help in effecting this? These are just speculative questions but asking them can open up new ways of looking at these discoveries in a new light and proceed further in novel ways.