So we know that one of the benefits of consistent long runs is increased capillarization around the exercised muscle. So what happens when you go into a period of reduced mileage, or stop training altogether. Do the capillaries atrpophy and eventually go away? Or do they remain and work at reduced capacity? I've wondered this for a while, but have never seen it addressed.
This caused me to do a bit of research which is a good thing. As best as I can tell:
If you have only been exercising for a few months or even for a year or two, about three months of inactivity will send you back to a completely untrained state. If you have engaged in intense exercise, and that means more than just jogging every day, and you have engaged in that intense activity for several years, the results are different.
1. VO2max declines rapidly for the first month and then gradually declines for approximately another two months until the untrained VO2max level is reached and VO2max doesn't decline further. Nevertheless, VO2max remains higher for highly trained individuals than for untrained individuals even after complete detraining. it is unknown whether they had higher VO2max to start or whether this is a retention of the training benefit.
2. Mitochondrial activity is totally reversed with three months of detraining in moderately trained subjects but partially retained in highly trained subjects.
3. Increased capillary density is not lost in highly trained subjects but is lost in less well trained subjects.
It is possible that highly trained subjects had a greater genetic capacity to engage in intense training for many years because their mitochondrial and capillary capacities were higher than that of the general population and they really are reverting to a completely untrained state. It's just that their untrained state is significantly higher than the untrained state of the general population.
Short term goal: 17:59 5K
Mid term goal: 2:54:59 marathon
Long term goal: To say I've been a runner half my life. (I started running at age 45).
What he said.
in our family experiment of N=1 when my husband crashed and shattered his clavicle, I can tell you that it took him about 6 weeks to get back on the bike totally (he rode the trained after about 2 weeks, but no weight bearing on the arms, so really not anything more than spinning out his legs) and not on the road riding until 12 weeks.
He was in peak condition racing Cat 3 prior to the accident and came back stronger the following year with a FTP increase (functional threshold power).
In his case, the time off was not terribly detrimental, but he crashed in early July and would have been headed into a base season when he was getting back out on the road, so who really knows the true impact other than a lost racing season. Trust me, I heard about that.
Don't forget that you also get a slight decrease in cardiac output when you are off for that long as well. A decrease in red blood cells and blood volume will also occur (you increase blood plasma in a trained athlete-some will appear anemic as a result, but they may not be). This explains why some athletes appear to be anemic, but have a normal RBC production and size.
Thanks LTH, I kinda aimed that question at you with a hand grenade, and from a training aspect it confirms what I suspected. Although I still wonder, what happens to that tissue? Does the body decide its not needed anymore and convert it into something else? Does it wall it off like sn underused subway line to lie dormant? This is the place my mind wanders to on a long run.
Your body will break down the tissue for other uses. You can even lose cardiac muscle when you quit training.
3/17 Shamrock Marathon
4/20 North Coast 24 Hour
7/27 Burning RIver 100M
8/24 Baker 50M
10/5 Oil Creek (distance to be determined)
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I bet it's converted to other uses. The body is continually remaking itself, even adding and removing bone. As I understand things, pretty much only teeth are "set in stone" if you will, and don't change at all.
What Banshee and Ann said. Even your bones completely remake themselves over time and exercise has an impact on this as well. When you stress your bones, they become stronger. If you quit exercising, your body will reabsorb that extra bone and use the calcium for other things.
Two things to add to what LTH said:
1. It takes about 10-12 weeks for any statistically significant physiological changes to occur.
2. Your metabolic processes start to slow down in your mid-twenties. So while you continually re-make and regenerate cells, it happens at a slower rate as you get older.
And it really slows down in your fifties.
So in other words, since it has been almost 3 months since I last ran, I'm going to have to start a C250K program to come back? Crap.
Huh, I have a blog?
Your lungs will sear from a 2 mile shuffle.
Couch to 50K ?
Sounds about right for you.
5K 23:21* (Vdot 41.53) 10/13/12
10K 51:48 (Vdot 38.39) 7/15/12
HM 1:46:23 (Vdot 41.95) 11/9/13
FM 4:28:33 (Vdot 33.01) 11/12/11
*Gun time, all others are chip time