As the clocks go back this weekend, so we move forwards into another winter season. This means a period of less sunlight and colder temperature that bring with it an unfortunate toll for us in a shift towards particular medical conditions.
The cold weather season sees a large spike in viral infections- most commonly ‘cold’ and influenza viruses. These viruses will often exacerbate any underlying chest condition leading to chest infections (pneumonias) and asthma attacks. Throat infections and vomiting infections like norovirus are also typically winter diseases as we spend more time indoors and in enclosed areas sharing air with others, resulting in the transmission of these pathogens.
Being out in the cold weather also brings hazards. Anyone suffering from poor circulation will be more symptomatic, including those with Raynauds Disease whose hands and feet are very sensitive to colder temperatures. Colder weather has also been proven to be associated with a higher incidence of heart attacks in populations.
The lack of sunlight is also a challenge to our bodies which evolved in more tropical climates accustomed to year round bright sunshine.
Vitamin D- essential for absorbing calcium from the diet and maintaining healthy bones and teeth- is produced inside our skin by a reaction that is driven by sunlight. Therefore, as a result of the lack of sunlight, many of us become deficient in the winter. This can be easily treated with the help of vitamin D supplements that are widely available.
Seasonal affective disorder (SAD)
Further, the dark days and lack of sunlight also contribute to a now accepted condition called seasonal affective disorder (SAD)* which I will discuss in a little more detail. Although winter brings Christmas and New Year’s Eve and is considered the ‘season to be jolly,’ it is unfortunately quite the opposite for many people.
As the clocks go back and our schedules find little or no exposure to sunlight (as even the short days are cloudy) people can find themselves slipping into depression-like symptoms of low mood, low energy, reduced desire to be social and an increased desire to sleep longer. Other notable symptoms of SAD include an increased/reduced appetite, decreased sex drive, and decreased concentration combined with increased anxiety and irritability. The way to distinguish SAD from depression itself is to consider if this is a recurring pattern that occurs every year and only in the winter season. However, the winter can also heighten other forms of depression in people who already suffer from it.
The exact cause for how this happens is not clear. The predominant theories are that winter reduces the levels of the brain chemical serotonin that is responsible for making us feel happy, increases the level of melatonin that makes us feel sleepy and/or disrupts our circadian rhythms (‘body clock’ processes.)
Given that we cannot influence the weather, the treatment options are focused at trying to reverse these potential causes within ourselves. Not surprisingly, a much touted treatment is a light box- a table top size box that emits bright light with the recommendation to sit close (but not too close) to it for 30-60 minutes a day taking care not to look at the light directly- which mimics natural sunlight. A more expensive option is the winter sunshine holiday(s) if you are fortunate enough to have this option!
Medical treatment consists of increasing the levels of serotonin by taking the SSRI group of drugs, for example fluoxetine, starting in autumn and continuing through until spring. Both SSRI drugs and light box therapy have separately been proven to have some beneficial effect on symptoms and this effect in both cases can be further augmented by regular exercise.
Last update: 15-12-2018