Watching a child
cry while they get poked by a needle can be gut-wrenching, but the stress
experienced by the child may actually be beneficial. While stress has long held a bad reputation
for being harmful, recent evidence provide a new perspective on the influence
of stress on human health. Although
chronic psychological stress is associated with immune dysfunction and
increased risk for a wide variety of conditions/diseases, acute stress enhances
many feature of the immune system and actually can protect an organism from disease.
Firdaus
Dhabhar and his colleagues at Stanford University found that exposing mice to
acute stress before they were vaccinated boosted the immune system and made the
vaccines more effective. Dhabhar
observed similar results in humans. Patients
anticipating knee-surgery increased the number of immune cells circulating in
the bloodstream in the days preceding the operation and had better
post-operation recovery compared to non-stressed patients. These results seem to make sense from an
evolutionary perspective; just as the acute stress response increases the
functioning of the cardiovascular system to prepare for fight-or-flight, acute stress
also appears to improve the immune system in the case of injury or infection. While the underlying
mechanisms for these findings remain unclear, there is some evidence that these
effects are mediated by stress-induced hormones, danger-associated molecular
patterns (DAMPs), microbial associated molecular patterns (MAMPs), and the inflammasome. Regardless of the mechanism, it appears safe to conclude feeling anxious
about receiving a shot is something that should be celebrated not embarrassed about
(even if you are no longer a child).
I think I've successfully set up my account....
ReplyDeleteNo need to hold back the tears the next time I go to get a shot, its always good to have a scientific explanation for sobbing.
ReplyDeleteThis is interesting to read. Before I had taken exercise physiology I had the mentality that when I had an upper respiratory infection I would to go "work it out" by exercising. However, I learned that certain intensities of exercise actually suppresses your immune system short term and in the long run improves your immune system. A triathlete website documents "experiments on animals and humans that have demonstrated that when they exercise regularly at moderate intensity for periods of up to an hour a day, the number of immune cells circulating in the blood increases." In contrast, exercising at a higher intensity for prolonged periods of time actually suppresses the immune system. I know this isn't in regards to infants, but I thought it was interesting to see stress on the body from exercise and how if impacts our immune system. JC, you're the expert on stress, is this accurate information? I am sure there is more to it....
ReplyDeleteLiz you are right to conclude there is more to it. First, it is often difficult to interpret the meaning of changes in circulating WBCs in response to a stimulus. For example, a reduction in circulating WBCs might indicate a suppressed immune system (bad) or it might indicate that the WBCs have migrated to a tissue in preparation for infection (good). Second, the literature examining the impact of exercise on immune function is very nuanced. Different types of exercise, at different workloads, in different populations, have different impacts on a wide variety of cell numbers and functions. A thorough review is found here:
ReplyDeletehttp://www.ncbi.nlm.nih.gov/pubmed/21446352