At least once in one’s lifetime an individual may be able to relate to experiencing the dreadful fatigue, fevers that are associated with an influenza infection, or the flu as most of us call it. As most are aware, this year is turning out to be an especially terrible year for influenza, with at least 47 states experiencing widespread infection and pneumonia and flu-related deaths reaching 7.3%, a number that pushes us past the epidemic threshold.
In Massachusetts alone, we have already seen 18 flu-related deaths and have seen over 750 confirmed cases in Boston. At this point last year there were only 70 confirmed cases in Boston, which demonstrates the vast difference and reasoning behind such a strong push for vaccination.
There’s no doubt that the flu can be devastating. In fact, a 2003 study by CDC scientists estimated that an average of about 36,000 deaths per year are associated with the flu, with each year ranging from around 5,000 to 52,000 flu-related deaths. These deaths are typically not seen in the very young and the old, whose immune systems are either still developing or have been compromised for whatever reason.
Though it may seem basic to some, a brief discussion regarding what the flu is and how it can affect us is essential before delving any further into the subject matter. The flu, as previously stated is the colloquially shortened name for the influenza virus, which is a member of a larger RNA virus family known as the Orthomyxoviridae group.
So what does this mean? Well, a virus is a very small infectious agent that can only replicate inside of a living cell. They can infect all sorts of organisms from bacteria to humans, but they’re distinct in that they are particles that are not living on their own.
Viruses are typically made up of two or three different parts:
- A protein covering around the outside for protection
- Occasional fatty layer around the protein layer to protect it
- Genetic material (DNA or RNA)
To infect us, virus must either attach to specific receptors on particular cells in our bodies or use their outer protein coats to attach to cell surfaces. Once the virus has “landed” on the cell it then penetrates the cell membrane by fusing or being taken in by our cells. This is when they get even craftier.
Once inside of the cell, the virus undergoes something referred to as uncoating, in which the protein coating is removed to expose the viruses genetic material and some functional proteins. This genetic material can now be incorporated into the host cell’s genome so that it can be replicated for the virus to reproduce. The newly formed viruses are then released when the cell lyses/dies and are free to wreak havoc on more cells.
The reason that most viruses simply run there course and we feel better in about 7-10 days is due to the fact that our bodies’ immune systems can detect foreign particles and mount a defense against them by self-killing infected cells and sequestering infectious particles with antibodies directed to specific proteins. This is this part of our immune system that we use in order to create vaccines to help fight influenza and other viruses. When we give a vaccine to we are either injecting a killed or inactive virus/viral particles in order to stimulate our immune system to make antibodies against the virus or in some cases injecting preformed antibodies in individuals whom need the antibodies right away.
Because of such rapid life cycles, viruses are prone to mutations, which are critical to their perseverance and success. One can think of these mutations as if the virus is changing it’s coat to avoid detection by the immune system. These mutations allow for the virus to “outsmart” our immune systems and are what lead to epidemics and pandemics.
Each year the flu vaccine is created by a group of scientists who predict the next years predominant stands. They have to take into account that the influenza virus commonly and rapidly mutates as well as the fact that influenza comes in three flavors A, B, and C, which can infect various different mammals and birds. It’s a complicated process and typically has a moderate success rate. In fact, even this year with the epidemic we are facing, the vaccine is 62% effective in preventing the flu.
This must leave one wondering, what the flu has to do with exercise or vice versa? Well, almost everyone is aware that exercise is beneficial for our health and can help reduce the risk for strokes and cardiac events, as well as obesity and diabetes related problems. Furthermore, anyone who is familiar with some of my previous articles is probably aware that I love to share some of the lesser-known benefits of exercise as well. And as many of you may have surmised from the title, exercise may be beneficial in helping to prevent the flu as well.
Though it’s not groundbreaking, and it’s certainly not surprising, recent research in the past few years has shown that exercise helps to not only improve resistance to infection and reduce the viral load in those who get sick, but also to help modify and influence how well influenza immunization may work.
I know at this point, there are certainly going to be people thinking to themselves, “well if exercising might help prevent me from getting sick, will it help me at all while I’m sick because I always thought it was “bad” to exercise when one is ill?”
While some home-remedies and traditional medicines may help alleviate symptoms there are some “old-school” thoughts that may not be completely accurate. Though rest and recovery are essential to help us fight a cold/virus, a 2009 study from the Journal of Infectious Disease and presented in part at the ACSM conference suggested that chronic exercise, or exercising daily for a long period of time will result in reduced virus symptoms, viral load, and levels of inflammatory markers when an individual gets sick. Even more interesting, was that they concluded that even with acute exercise, there were some benefits that were limited to the early phases of infection.
Such evidence suggests that there is a clear role in exercise helping to prevent and positively influence the course of infection. And though rest is generally helpful in ensuring enough energy be diverted to our immune system, it is probable that light to moderate exercise may offer some help as well.
As for the influence of exercise on the responsiveness of the yearly flu shot, several different studies have examined the effect of moderate exercise on both salivary antibodies and serum antibody/inflammatory markers after the administration of the vaccine.
A study from 2002 examined elderly individuals (>62 years of age), who were categorized into three groups: active (≥20 min vigorous exercise three or more times per week), moderately active (regular exercise but with less intensity, frequency, and/or duration), or sedentary (no exercise). They then examined the patients’ blood two weeks after the administration of a flu vaccine to assess it for antibody formation and markers of antibody formation/immune response.
What they discovered was that the formation of anti-influenza antibodies was greatest among the active group when compared to the moderate and sedentary groups. Furthermore, it was shown that the sedentary group displayed the lowest anti-body response to the vaccine.
This data suggests that lifestyle factors such as exercise may significantly help enhance our immune response after receiving the vaccination and consequently help better protect us against the flu.
So as one can see, exercise may not be the “magic bullet” that can cure everything, but it certainly is something that comes pretty close by helping to influence, alleviate and possibly prevent a wide range of medical problems. Hopefully this review helped provide a basic understanding about viral infections/influenza as well as an interesting look into yet another way exercise is critical in keeping healthy, strong bodies.
For more information regarding influenza and vaccine availability in Massachusetts, please check out: MyLocalClinic for listings of flu clinics and vaccine availability.
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Klentrou P, Cieslak T, MacNeil M, Vintinner A, Plyley M (2002). Effect of moderate exercise on salivary immunoglobulin A and infection risk in humans. European Journal of Applied Physiology; 86 (2):153-158.
Kohut ML, Cooper MM, Nickolaus MS, Russell DR and Cunnick JE (2002).Exercise and Psychosocial Factors Modulate Immunity to Influenza Vaccine in Elderly Individuals. The Journals of Gerontology; 57 (9): M557-M562.
Parham P (2009). The Immune System. Milton Park, UK: Garland Science Publishers.