/ Science / Health and Body / Ask a Doctor: Cite Why do our temperatures rise when we are sick? Temperatures rise in our bodies to fight infections. Fevers create an environment that, we hope, is too warm for the invading organisms. Turning up the heat makes viruses and bacteria feel unwelcome. Why does a bruise turn colors? How does a scab form? Q&A about the Body Download Poptropica and play for free!Explore a limitless universe of uncharted islands See also: How do we get sick?