IMO the studies cited there mirror the results with the mice, so the best bet is to run the 30-75 minutes recommended in the Runner's World article, not several hours as used in the experiments.
In the first experiment's and 2nd experiment's experimental group, it sounds like the mice over trained. It's a commonly known phenomena among athletes and these symptoms certainly sounded like it.
It would have been more interesting if they had trained the mice up over a longer period of time and then exposed them to flu.
That would be a much more interesting experiment, and closer to what human athletes do. Any athlete who is serious about training also schedules rest. It's during the rest that you actually get stronger and better conditioned.
Yeah, a big reason people exercise is for the long-term health benefits. Of course the study is interesting, but not as something that should directly affect personal workout routines.
Exercise for officer workers is definitely needed, however there are serious side effects to over-exercise. Not only can it be counter-productive (increasing the time to actually get physically fit) but opens you up to prolonged infections.
The big problem is that lack of rest between exercise can increase the risk of strokes and other circulatory problems, which is extremely counter productive. Damage to connective tissue and the consumption of muscle tissue during exercise can have life long effects (for anyone who doesn't know, your heart is a contractile protein, which is the type of protein consumed during excessive exercise periods).
Regular and regulated exercise are the key to health, and it has to be a regimen built for you. For some people over-exercise can be beyond a 20-minute light jog, for others it's a marathon. Not everyone is a marathon runner or body builder and believing differently is dangerous to your health.
I do 30 minutes of treadmill every day (between 6 and 9 Km/h, with 4%-12% inclination) and my feeling is that my body really enjoy this. It seems natural btw that stressing too much the body is not a good idea for your immune system.
It's rather logical in fact. When you exercise you damage your body, keeping your repair mechanisms active.
However overexercise typically does more damage in a session than your body can heal before your next session. It's rather safe to assume that when you contract a virus that when the immunological warfare is going on (our bodies first response is rather brutal and untargeted, the sore throat from a flu isn't from the flu, it's from your own immune cells killing - IIRC - roughly 20 healthy throat cells for 1 infected cell) and damaging our body that the repair mechanisms are coping with all too much.
Not exercising doesn't put stress on our healing mechanisms, however it doesn't keep them active and trained (so to speak). Put it this way, the Police would take considerably longer to get to your house from the station than from one of their patrol routes; essentially the same is for our healing mechanism.
Even if exercise doesn't have an effect on our immune system, I'm sure it will certainly increase recovery time (assuming you're not on the treadmill when sick) by decreasing healing time, which is ostensibly the factor that kills you and not the virus itself (assuming you haven't contracted the 1918 Spanish flu).
I've only ever had one noticeable case of the flu (which happened when I moved country, so I'm unsure if it was a strain I'd never experience, similar to the current H1N1 'pandemic'), which I believe is due to frequent exercise (a job involving heavy lifting ~90lbs and constant weight carrying ~10 lb tool pouch and ~10lb hammer drill).
Thanks, interesting explanation. Maybe another factor is the change in blood pressure, because while you exercise parts of your body that normally receive little blood, will receive a lot more, and blood carries antibodies that may kill viruses before they start to spread in the rest of the body.
I noticed that sometimes when I had a start of a cold, but still feeling well, to exercise lead to a stop of the infection.
Yes, your body has X resources available for maintenance activities at any one time. If you need to recover from exercise AND fight off infection AND keep yourself warm and you exceed X then at least one thing is going to operate at a reduced capacity until another has caught up sufficiently to free up some capacity.
What would be nice is if you could tune it e.g. "I don't mind my muscles being sore for an extra day but I really don't want to get ill".
What's missing here - and which you can't really test with mice - is the emotional side of things.
Exercising because you've been placed on a treadmill, as was the case with the mice, is akin to people exercising because they "have to", or get a trainer to "stay motivated". When you actually do it because you "want" to and it feels good it's a different story because the feelgood chemicals have a lot to do with your immune system.
For many years during my late teens and early twenties I went to the gym so that I could get buff and be fit. I hated exercise, but forced myself to do it and pushed through the pain. Yes I even got a personal trainer at one stage. The results? I either got sick, injured myself, or just plain depressed (at the lack of results), only to repeat the cycle over and over again.
Back to this article - what I'm trying to say is that stress, anxiety, happiness all play a HUGE part in your immune system (and fitness).
I do regular strenuous training, and this makes sense to me. You are weaker immediately after a strenuous workout than immediately before. That's why adequate recovery time is just as important as workout time. It makes sense to me that immediately after the workout, before your body has had a chance to recover, your immune system is weakened and you're more susceptible to illness.
Personally, what keeps me coming back to my workouts is the challenge. I'll take the extra risk of the occasional cold or flu over the risk of dropping my workouts entirely from disinterest.
Ha, I've never had my workouts compared to smoking. My workouts have many other positive benefits, which I think outweigh the risks. Smoking has no positive benefit other than it's something to do while sitting in bars.
Like anything in life, it's about balance. Eat healthy and balanced diet and exercise 3 to 4x a week. If you over extend yourself, you will get hurt or sick. Ditto if you do nothing and overeat.
My personal experiences match the findings of these studies. My diet and supplement use is much better during heavy training and exercise periods, so I'm hoping that that will offset it.
er, what about the second experiment, where light exercise reduced infection to 12% versus 50% for no exercise and 70% for 5x as much exercise?
that seems to suggest that doing a little bit of work keeps the body healthy.
furthermore, the study doesn't say what the mice did before the experiement. perhaps the mice were used to 20-30 minutes of exercise a day, and it is change that is most damaging. what one mice considers exhausting, another mouse might find boring.
edit: the article mentions "(Although definitions of intense exercise vary among researchers, most define it as a workout or race of an hour or more during which your heart rate and respiration soar and you feel as if you are working hard.)"
Not going to touch on the finer points of the atheltisim of the mice. As your right it would clearly alter the results.
But I do have a question.
What is the ratio of 30 minutes of exercise for a mouse compared to a human. As I would be highly surprised if its 1 to 1.
This article reinforces the need to listen to your body and react accordingly.
On a side note for those looking for ideas.
Based on the example in the article...
I would happily volunteer to take a saliva test before running and after. To help build up the data available for the test.
A website to cater for "crowd sourced data" scientific discovery would be an amazing site. ( clearly there would be pitfalls, im just throwing it out there )
patientslikeme.com is doing crowdsourced "scientific discovery." I use quotes because of the obvious difficulties in having proper scientific procedures in crowdsourced efforts, but nevertheless I think it's useful.
"running leisurely for 20-30mn" is not hard work, so I guess you won't have a hard time recovering from it, if at all. OTOH a real challenging workout requires a recovery period, since it causes some "damage".
Looks like the body has trouble fighting off a disease while recovering from hard work. But no physical activity at all has a debilitating effect. It makes sense.
In my experience I never had trouble fighting a disease when I work out hard; I guess it has something to do with a better diet and better sleep quality.
When an injury or real life makes it next to impossible to train, I usually get sick more often. But you're right, I'm speaking only of my own experience.
Though it's bizarre to hear it applied to this topic, you've given a very concise example of a particularly insidious kind of trolling: make vaguely resentful statements about the forum that add nothing to the discussion. I estimate that this makes up maybe 10% of the comments on Reddit with negative scores, and their prevalence rose as the level of discourse dropped.
How many flights of stairs? I used to live in floor 5, and can run up all the way without getting out of breath. However I tried to run to floor 16 in a hotel a few days ago, and was powered out around floor 8.
My personal experience matches:
http://www.runnersworld.com/article/0,7120,s6-241-285--12386...
IMO the studies cited there mirror the results with the mice, so the best bet is to run the 30-75 minutes recommended in the Runner's World article, not several hours as used in the experiments.
R.I.P. mice.