The fact that most people become sleepy and tired in the cold season makes a perfect sense if we know how human biorhythms coordinate with the environment. The lack of natural sunlight stimulates the production of melatonin which makes us feel tired. Apparently, this natural mechanism resembles hibernation to some extent: humans are meant to save their energy in the winter going to bed earlier and waking up later. However, this necessity does not fit in our business schedules as we have to be highly energetic and attentive at work irrespective of the external conditions.
Office workers usually show a strong dependence on the weather conditions. Natural sunlight is the first thing which is likely to improve their well-being, however, when the clouds are dense, these people shall have a good substitute to reinvigorate themselves. In the first place, it is good to have a bright natural-like lamplight in the office. Next, it will be nice to set the appropriate medium temperature in the room to feel comfortable while working. Physical exercises can give a certain boost of energy which will enhance mental activity and improve the quality of work. And last, nutritious food will help to recharge the batteries and supplement the energy loss which appeared due to the lack of sunlight.
Access to the natural light is crucial for us to maintain everyday activities as we always do. That is why we have to make sure that we receive sufficient amount of sunlight in spring and summer and that we can substitute it in winter when sunny days are uncommon and short.