Posted on by johanne_marais

Sleeping more and moving less? Thank the suprachiasmatic nucleus!

The winter solstice rolls us into the second half of the solar year. Trees surrender their fiery leaves to frozen dewdrops on bare branches. Shorter periods of daylight and longer portions of night lure thick socks and hot water bottles out from a deep drawer of winter clothes. Hearty stews simmer and fires frequently flicker as the season shifts. Animals seek warmth and reprieve from the cold by “… migration, hibernation and resistance (tolerance)”. For many humans, winter may burgeon these types of adaptations too, encouraging changes to our appetite, our exercise patterns, even our sleep and wakeful behaviours! Unpacking the physiology of this can help us be kinder to our bodies and minds for embracing our inner polar bears during winter months. So, allow me another moment of sleep science nerdery…

An intrinsic, 24-hour, regulatory system is present in each of our bodies. The system is called the circadian rhythm; internal oscillations that cycle around a biological clock. Some molecular mechanisms of the biological clock are retained across plant and animal kingdoms – from the most primitive single-cell organisms like cyanobacteria to human beings. In mammals, the circadian rhythmicity is observed in fluctuations of hormones, sleep-wake cycles and even periods of optimal cognitive functioning. Genetic variables of circadian rhythms are by no means conserved across species, and especially not within the same species.

Your 24-hour structure may differ from your housemate, sibling, or colleague by up to eight hours. This depends on microenvironments within and macroenvironments around the body. For example, your sibling, a shift worker who drives shipment trucks across the country, might wake up at two o’clock in the morning to arrive at their destination by four o’clock that afternoon. Their bedtime may be 6pm. At this time, a night nurse who clocked in at Rahima Moosa moments earlier may be enjoying his equivalent of a “morning coffee” and prepares to work through the night. How can this vary so vastly (and manageably) from person to person?

In brief, the answer is light and chemistry!

The circadian rhythm’s master-regulatory site is called the suprachiasmatic nucleus – a cluster of thousands of neuronal cells in the brain, situated on top of the optic chiasm. The suprachiasmatic nucleus (SCN) is receptive to photic stimulation (think: packages of light called photons sent via the visual system) and chemical (or, neurotransmitter) stimulation. The SCN’s sensitivity to light means that timely exposure to or limitation of daylight can shift the phase of our circadian rhythms; we can feel a desire to sleep earlier and wake up later, like with shift workers.

This is happening across the world as seasons change: a phase shift of circadian rhythm aligning with Earth’s orbital cycles and environmental cues. During winter, the sun sets about 90 minutes earlier than it would in warmer months – it may be a challenge to stay awake until your 11pm summer-bedtime. Similarly, the 5am Club may lose a few committed members (not mentioning any names erhuurhm @me) between May and August. Frankly, if the Sun can go to sleep earlier, so can I! This is an expected adaptation; a sign of your body adjusting well to its circumstance. No big deal!

It is also common for emotional affect to change in winter. Ever heard of Seasonal Affective Disorder? It’s basically the SADs that often come with less sunlight exposure. Our mental health is a huge determinant of our sleep-wake behaviours, too. People who live with a psychiatric illness (or even symptoms of one) are considerably more likely to experience coincident insomnia – up to 90% coincidence! This relationship, though, is no coincidence. Several molecular messengers involved in sleep, wakefulness, appetite control, and mood regulation are in the same class of neurotransmitters called monoaminergic neurotransmitters.

Just as animals do, humans may migrate smaller distances in winter: like, no further than to the snack stash and back. So, maybe we gather a little more belly fat. We don’t have that spring (haha, get it?) in our step. We want to sleep in… Guess what? Colder times of the year welcome a series of natural and protective evolutionary traits to be expressed and experienced. Sometimes that feels like seven extra centimetres between your skin and your belt buckle or admitting you simply must rest for 12 hours every day. Just as we do not look up at leafless trees nor look down at frost on the grass with judgement, there should be no shame around the physical, psychological, or physiological changes that come from seasons changing. If you’re sleeping more and moving less, give thanks to the suprachiasmatic nucleus!

Posted on by Lonwabo Makapela

What I love about Winter

Well, the first semester is done and dusted. Though much of it is a blur, the temperatures are now beginning to drop, colours fading, trees becoming bare, the air crisp, and nature is hitting a pause on growth; I thought to do the same, and upon a bit of reflecting, I realise that I have had a disproportionate amount of Winter over the last 12 months. Having left for the U.S. in August and returning to South Africa in May means that I left just as Winter ended, lived in the U.S. all through the Winter, only to return to South Africa as Winter started again. Something about that seems poetic, so shall I compare thee to Winter?

First, many of my blog posts on the PhD/research journey have been quite sombre. And though I acknowledge the winter blues and all its stressful and anxiety-enhancing oddities, I have decided to dig a little deeper today and explore the magnificence of the little light we see in Winter. So, what exactly is it that I love about Winter? Let’s get to it.

Travelling

Once winter break hits, most of us travel home, and if not, we travel somewhere with family and friends. Similarly, one of the best perks of being a researcher is the opportunity to travel. If not to collect your data, you are attending conferences, and workshops, taking up visiting research positions all around the globe. What’s even better is that research trips are often funded in a way that allows travel costs to be taken care of. Travelling brings many benefits, such as exploring different cultures, alleviating stress and anxiety, drawing inspiration, and creating unforgettable memories.

Eating steamy stews

Conceptualising your research ideas resembles the making of an excellent steamy stew in the sense that when making a heavy bottom stew, you add your many ingredients to the hot oil, the cuts of meat are tough and need a significant length of time to break down – it takes time to develop great flavour; therefore, the heat must be slow and gradual, never fully reaching boiling point, and occasionally removing the soup from the heat. This process may be long-drawn-out, but nothing warms us up like a steamy stew on a wintery evening; it fills your heart with warmth and is soothing to the chill of Winter. So, give yourself time to do your thing, but be sure to get cosy and enjoy the result!

Layering all your favourite clothes into one outfit

It’s hardly possible to predict Winter forecasts at times. It could be rainy on one day, freezing the next and warmer than average temperatures the next. This sometimes makes dressing for the weather difficult. However, reminiscent of choosing suitable theories to support your research, selecting the appropriate inner layers for your outfit is essential. The delicate and fun nature of layering means you must be sure to layer the clothes both fashionably and functionally. You can experiment and play with garments in your closet and allow your creativity to shine through. So, give yourself the leeway to experiment with various colours, patterns, and textures for infinite possibilities.

Days off!

With research, life can often become a go go go, as we get wrapped up in the stresses. But this can take a toll on your brain, body, and spirit. Without a doubt, we are all wrestling with this realisation and having to decide whether it would be wise to take a break. This reminds me of the extreme weather conditions this time of the year, particularly in the Eastern Cape, where driving conditions are less than ideal due to heavy snowfall, which leads to a closure of the mountain Pass. These extreme weather conditions forcefully assign a day off to many. Therefore, feel free to take a break on those rainy, snowy days and whenever needed. Sometimes, cosying up to a hot beverage, snacks, and Netflix is just what you need.

Planning your spring

There naturally comes a time, usually towards the beginning of July when I start daydreaming about spring and the new semester. Granted, as a PhD student I don’t have an explicit winter break, but due to habit and emptiness of campus around this time, I feel prompted to take some time off and start planning for the new semester – looking forward to the newness and bloom of spring gives my spirit a boost. Having something to look forward to, can make the world’s difference, so start making those warm-weather plans now!

Ultimately, the winter season brings forth colder months and shorter days. And although the best part of nature is going to sleep due to frost in the air and the low temperatures, the colours of the dying leaves are magnificent.

‘If winter has the courage to turn into spring, who says I can’t bloom just the same’ Sian Wilmot.