Historically we only ever worked outdoors; two hundred years ago, 75% of the population worked outdoors now, less than 10% of the population worked in the natural outdoor light.

Whilst this is fine in the Summer months when there are longer daylight hours, in the winter months, people tend to go to work in the dark and go home in the dark and don't get enough natural daylight.

This modern way of living has dramatically altered nature's cues. A modern-day no longer starts at the break of dawn and ends at sunset. Workdays are getting longer, and many people face shift work schedules.

Additionally, the advent of electric lighting allows social gatherings and personal activities to extend well into the night.

These factors have diminished the body's natural ability to regulate the body clock, and this work/life change has resulted in a dramatic increase in light deficiency symptoms.

 In the UK and Ireland, we are more susceptible to SAD as we are situated in the higher latitudes of the northern hemisphere.

As a result, we experience significant changes in light levels between the summer and winter. We also experience dark, gloomy weather periods, which can reduce the amount of light we receive and, therefore, profoundly affect our body clocks.

A combination of a change in seasonal light, our hectic lifestyles, and the periods of darker days and poorer weather can dramatically affect our circadian rhythms.

As a direct consequence of these environmental and lifestyle factors, more people than ever before suffer from Seasonal Affective Disorder.

Speak to your GP to see if you suffer from SAD.