Science Questions

Why is illness worse at the end of the day?

Whenever I feel ill, I feel a lot better during the day and then my symptoms get a lot worse just before I go to bed. I feel like I’m getting over it and then at the end of the day I feel ill again. Why does this happen? Jake, US

We put this question to Dr Clifford Leen:

Clifford: When you’re ill your energy levels are a bit lower than usual. In the morning you’re fresh and if you use all the energy before the evening then you’ll feel tired. If you pace yourself and do work in small packets over the day you’ll probably be less tired. It’s like a battery.

March 2008