Naked Science Forum

Life Sciences => Physiology & Medicine => Topic started by: Jessica H on 01/10/2010 03:46:45

Title: What makes you feel weak when you're sick?
Post by: Jessica H on 01/10/2010 03:46:45

Does the inflammatory process somehow make you feel weak when you're fighting off a virus?  Or are you just running out of energy reserves?  Where does this weak feeling come from?

Title: What makes you feel weak when you're sick?
Post by: chris on 01/10/2010 12:03:20

Hi Jessica

the lacklustre feeling associated with ill-health is a consequence, as you correctly surmise, of the inflammatory process. Signals called cytokines produced by the immune system to marshall the components of the body's immunuological army also have the effect of triggering a sense of tiredness, appetite loss, fever, chills and myalgias (aching muscles).

One could argue that the "benefit" of feeling like this is that it forces the person to take life easy for a bit to avoid energy being expended on things other than the immune response, while the foreign invader is fought off.

Some of the ill-health feeling is also a self-fulfilling prophesy because if you feel ill and don't eat and drink properly (or you have a sick bug) then you may well develop short-term metabolic disturbances and calorie deficits, which will exacerbate the sensation of general lassitude and "grottiness"...

Chris