Health, Illness, and Animals

I've been looking into how animals behave when they are ill.  For example, here's one study that discusses the behavior of sick animals.  It mentions that animals generally do the following when they are ill:

• Fast completely
• Drink very little fluids
• Become "lazy" and rest
• Withdraw from social activities

The paper goes on to show that this set of behaviors is in fact adaptive, as it helps to isolate an animal so it can recover.

I wonder why these type of behaviors aren't turned into recommendations for when a person is ill.  Rest is usually prescribed, but the opposite advice is given on fluids: someone who is sick is supposed to drink more.  Also, fasting is hardly ever prescribed.  Usually it's "feed a cold, starve a fever", but the truth is it's probably better to fast under either condition. 

And the idea that fevers need to be reduced also bothers me.  Evolutionary medicine shows that fevers are adaptive responses as well, and they should not be interfered with unless the fever gets extremely high.  A fever is the body's way of turning up the core temperature to fight infection.

Another part to this is exercise recommendations.  Some people recommend that if the symptoms are "above the neck", that a person should continue exercise, though they should decrease the intensity.  I could find no research to show that this is healthy.  What's more likely is that any heavy exercise will add to an ill person's level of inflammation and delay healing.  For example, this article shows that an event that increases inflammation (pollution) makes colds worse.  Therefore, it's likely that any type of intense exercise (which increases inflammation), would also make a cold worse.

I think the advice to keep exercising when ill probably was designed with athletes in mind.  If an athlete has an important event scheduled, they may choose to train through their sickness in order to perform better for the event.  But for a person whose main goal is health, I don't see any reason to exercise at all (beyond easy walking) when sick.

Comments

[Tobias]

Interesting article. Thought it was particularly interesting that bacteria need iron to grow, and that fasting is partially a mechanism for depriving bacteria of iron.

[Matt Metzgar]

Yes, you got me thinking more about how iron affects immunity. See the new post about anemia.

[Jeff]

Very good insight. I have been doing IF for about 2 months now. I have felt a cold coming on and fasted as a result. The cold receded. The animal observation makes perfect sense and seemed to work anecdotaly for me.

jeff