The time after Sunset and for about 2 hours on is known in astrology as the time when the Sun is in the 6th house- associated with Illness and health.Whenever the 6th house is activated somehow, one receives signals about his body condition-if something needs to be improved in the life style of the person, the body will inform him, by symptoms or outright illness.
Why is this position of the Sun, known as the sickness sector in Astrology?
Every day after the Sun sets and for about 2 hours, the body needs to adjust itself to the change of diminishing light and energy around it. The Sun-the major source of both, is no longer available and all living organisms need to realign themselves with the decreasing warmth and light. The body goes into a mini shock and compensates for the retreating energy by hunger for food and in case of humans, emotional hunger sometimes.
Body organs which are in beginning stages of imbalance, can start sending slight pain signals at this time of energy hunger and realignment. The vital energy of the Sun is retreating, so the sensitised organs are no longer supported and while the process of adjustment lasts, they create discomfort in you.
So next time the Sun sets and for about 2-3 hours after, pay attention if anything in your body starts hurting or just giving you discomfort, without an apparent reason. Observe if it repeat again over time. If so, it is a sign that this organ is starting to get devitalized and soon it will create more serious problems, if nothing is done.
Thankfully, the 6th house is not only the house of illness but also the house of improvements. Any illness caused by your own unhealthy life style is indicated in the 6th house(not accidents or karmic / genetic diseases, which are unavoidable/fated and indicated by the 8th and 12th houses), so 6th house is the place of self created illness, which can be reversed by change of habits, decrease of stress, more exercise, etc.. And it is proven that nowadays 80% of all diseases and pains are caused by such factors(ourselves)!
If you have been putting too much pressure on your body by indulging in wrong foods, being passive or overdoing, getting angry or stressed, drinking, smoking, etc, your body will warn you way in advance what is about to come to you, if you change nothing. And this pre-warning happens after Sun Set! So Pay attention! For example- I sometimes get stiff joints around that time, which is a great sign for forthcoming serious joint problems in the future, if I do not get off that couch and move! :)
There is another period which very telling about incoming illness, which is after the Moon sets in the Western horizon, but for this you need to watch the sky or check internet for the local time of the setting! Any discomfort in the body you feel then will be a sign of illness which reasons are usually psychosomatic(their root is in the emotional inner world of the person), so you might have to remove some painful relationships, memories or situations.
So go one, observe yourself and do what you have to save yourself maybe what might become years of pains!