I had just arrived in Finland and the sun was shining beautifully. Then I looked at my watch. Time 8 P.M! Something must be wrong.

Half an hour later, I checked the time. Besides, the sun was still out. Confused, I inquired from my Finnish host, who told me that it was summer (it was freezing) and the sun does not set until 10 pm.

Well, surprise, surprise. This was the beginning of a broken internal sleep clock. It took my circadian rhythm a while to adjust to life in the Northern hemisphere. In Kenya, the sun rises at 6 am and sets at 6 pm.