You don't have to be training at the level of an Olympic athlete to suffer from overtraining.
Before discussing overtraining, it is necessary to discuss how physical conditioning works.
Basically, the muscles are stressed by subjecting them to a combination of more load and a greater number of repetitions than they are physiologically ready for. That causes damage to them. Often the damage is in the form of micro-tears. The damage sends out chemical markers that signal the body to invest resources in healing and strengthening them.
After giving the body an appropriate amount of time to heal, the athlete stresses his body again.
A good training program considers the number of repetitions or miles, the weight or speed, the current condition of the athlete, the genetic endowment of the athlete and the athlete's age. All of those things come into play with regard to how quickly the athlete's muscles will have repaired themselves enough so an additional workout will add incremental speed, strength or stamina.
It means that an out-of-shape 60-year-old cannot condition like a 21-year-old Marine. It also means that after two years of working out you will be able to shake-off work-outs that would have totally incapacitated the pre-workout you.
Pinning down when you enter "overtraining" territory can be elusive. There are a boatload of symptoms and not every person in training will have all, or even most of the symptoms.
Right now I am hobbling around and have been experiencing the symptoms of a low-grade cold for a week. So there is a good chance that I am tickling "training too hard" and need to back off.
There are currently three technologies used to produce seasonal flu shots. Most of the vaccine is still produced using chicken eggs.
There are two big issues with vaccine produced from chicken eggs.
- Adverse reactions in some people
- Genetic drift in the H3N2 strains
I have never had an adverse reaction but I know that many people have had them.
The genetic drift in the H3N2 strains means that earlier generations of the vaccine production produce robust immunity to the strains expected to circulate through the community early in the vaccine production cycle. It also means that the immunity is LESS robust as more generations of virus cycle through chicken eggs.
One of the non-chicken-egg vaccines is grown in cultured mammalian cells. Specifically, they are grown in a culture derived from canine kidney cells. If H3N2 strains drift, they drift much more slowly than the ones grown in chicken eggs.
Yesterday, I went to Rite-Aid and got my seasonal flu shot. I asked if they had any of the vaccine made from dog kidneys. Surprise, surprise, surprise...they did! Flucelvax Quadrivalent.
MSRP is $59. Private sector, wholesale $25.76. After insurance and grants...no cost to me.
I already notice one side-effect. I am able to lick over 80% of the surface of my body.