If you find yourself struggling to stay energised, sleep well, and keep motivated during these cold, dark winter months, chances are you have some degree of seasonal depression or seasonal affective disorder (SAD). As the acronym aptly suggests, a lack of natural light can noticeably inhibit our ability to maintain a positive mood. Everyone experiences the biological effects of limited sunlight to some extent, whether we realise it or not. Especially living in a place like St Andrews, where daylight dips to just six or seven hours on the shortest days of the year, it is practically impossible not to be impacted by the relatively harsh conditions of our local environment.
It is important to recognise that there are different types of light and that they are perceived differently by the eyes and brain, thus eliciting a variety of reactions in the body. Sunlight is the most “natural” form of light and often reaches up to 10,000 lux. Compare this measurement to the brightest type of office or industrial lighting, which only reaches about 500 lux. This extreme contrast demonstrates why our bodies can be thrown off by the ratios of natural to artificial light in the summer versus winter months. In addition to brightness, different kinds of light have different effects. For example, blue light, which is emitted by most screens or LEDs, has a short wavelength and a larger effect on the circadian rhythm than light with a longer wavelength, such as red light.
The symptoms of seasonal affective disorder, which can include low energy, weight gain, and sleep trouble, result from a variety of neurochemical processes. Melatonin, the hormone that makes you feel sleepy, is often overproduced in those with seasonal affective disorder. When it’s dark outside, the pineal gland secretes melatonin and tells your brain that it’s time to sleep. Since winter brings an influx of darkness compared to other times of the year, the levels of melatonin produced in the body naturally increase, especially for those who are particularly sensitive to light.
Serotonin is the primary neurotransmitter that affects mood, appetite, and sleep. People with seasonal affective disorder have difficulty regulating serotonin and often experience varying degrees of depression as a result. Throughout the summer, sunlight generally keeps our serotonin levels at a healthy balance, but as light diminishes at the darkest times of the year, many of us struggle to keep this “happy hormone” in check.
The combination of increased melatonin and decreased serotonin impacts the body’s circadian rhythm, the 24-hour body clock that causes us to feel energised during waking hours and drowsy during sleeping hours. The way light alters the circadian rhythm depends on the timing of natural light exposure. When light is perceived early in the morning, it shifts our sleep schedule earlier, and when there is ample light late in the day, our sleeping routine is naturally pushed later. However, when there is very little light during waking or evening hours, the circadian rhythm can drift out of sync with the sleep/wake cycle, resulting in difficulty sleeping at night or staying alert during the day.
Although the science behind seasonal affective disorder may make you want to book a one way ticket to an equatorial island, there are many simple lifestyle changes that can make a massive difference in assuring consistent energy and positive mood, even on the darkest of days. Making sure you spend time outside in daylight everyday is crucial in ensuring these hormones stay balanced. A quick, mindful lunchtime or sunset walk will massively boost your mood, even if the sun isn’t shining. It is also important to hone your sleep schedule to a regular routine that works for you, ideally maximising daylight hours. As challenging as it can be (trust me, I would sleep until noon everyday if I could), forcing yourself onto an earlier sleep schedule during winter will make a world of a difference in maintaining a regular circadian rhythm. Ensuring that your home environment is as bright as possible will also help to boost energy and concentration, whether that be keeping curtains open during the day, incorporating ample lighting into your work space, or positioning your desk by a window. Additionally, light therapy is a go-to treatment for seasonal affective disorder. Exposure to specialised lamps that can produce up to 10,000 lux, especially right after waking up, can also be extremely beneficial for keeping your circadian rhythm on track.
The lack of light in winter is no joke, especially in Scotland. Although there are ways to combat its impact on the body, there’s no arguing with the fact that it can be very challenging and sometimes impossible to feel healthy and energised on the coldest, darkest days of the year. Being mindful of your time outside and positioning your day to align with daylight hours can be extremely helpful in keeping the body and mind aligned. But when all else fails, join me in counting down the days until 10pm sunsets, waking up to the sun beaming into your window, and golden hour all day long.