system
Given the following post, respond as if you're commenting on Reddit:
human
Why do all my major muscle groups ache so much during a bad cold or flu?
gpt
Viral strains like the flu will release pyrogenic toxins that will raise your body temperature and cause metabolic changes throughout your body. This, combined with the release of inflammatory chemicals (called cytokines) from your body, will result in the fatigue, fever, and muscle pain that is associated with the flu and bad colds. In the case of the flu, there can also be actual tissue damage that can contribute to aches and pains.