Cortisol - the general rule that I see floating around everywhere, is that 45 minute or 1 hour weightlifting sessions are "the thing" to do, because cortisol rises after that time.
My question is: where is the research done on this. Are we sure that if long rests are taken between sets, that the cortisol issue does not change?
For example, I am SURE that after 45 minutes of RUNNING, you'd be triggering cortisol.
But are we sure that if someone was to rest 5 minutes between sets (because that's what they needed), that the cortisol would still kick in after 45 minutes? Or does the cortisol kick change depending on many things. Maybe it only kicks in after 2 hours or 1.5 hours when long rest periods were taken. Were tests done on long rest period style workouts? Are we basing our 45 minute rule on tests that were done on high volume high rep style weightlifters?
I know a lot of people see a scientific test done, and then they apply it to everything. This could be the case with the "45 minute cortisol rule". It could also be that I am WAY off here, and that many tests have been done on cortisol, and that it ALWAYS in so many cases kicks in after 45 minutes, no matter what. There ARE situations like this in science. Where sometimes, it just IS, in all situations.
So I would like to know more about cortisol, and hopefully see a lot of different tests done with different variables. I don't just want to assume that cortisol is always kicking in after 45 minutes. It could be that this is a rumor, based on tests done with short rest periods.. or, it could be that it's just a magic number in many cases and 45 minutes holds true over and over again.
It would be interesting if the amount of rest between sets did affect the cortisol. As an example of why maybe the 45 minute rule isn't always valid: I'm guessing that if a farmer that lifted really heavy hay bails all day long, waited about 5-15 minutes between each set, he would still be a really BIG and strong person after doing this for many years. This is obviously not a 45 minute session that he's doing, he's doing it all day long but with long rest periods. Of course, it could be though, that he still didn't get as big as he could of, if he would have followed the 45 minute rule.
I'm not trying to argue with the 45 minute rule being wrong. I'm trying to learn more about it, rather than just accept that in ALL cases with strength training, 45 minutes should be used as a rule. It's as if it doesn't matter if we wait 2 minutes between sets, or 10 minutes, the 45 minute rule is always valid (roughly... 45 minutes, 1 hour, 50 minutes, etc.) But is it? Are there tests showing different weight lifting style routines (long rests, short tests, session times, etc.)? Is this cortisol rule not a rule at all, but just a rumor from a few tests that were done on some weight lifters that weren't even resting between sets? Or is it in fact a rule, because it has proven to be true in so many cases, even if the rest period was varied, and other variables were changed.
I know for sure that if you run hard or bicycle, or lift weights for 45 minutes straight without rests, you will have cortisol levels rise - but we can't apply this to strength training or power lifting. Are these the type of tests that we are creating the cortisol rule with? If you only did 4 sets of squats during a 45 minute session (say you did ten minutes between sets), is that going to release the cortisol at 45 minutes, or is that going to completely be different situation and maybe not release the cortisol until 2 hours later.
I know a lot of people see some scientific test done, and then they use it everywhere, quote it everywhere, etc. I hope this is not the case with cortisol. For example, if we saw a test done on cortisol that included a bunch of weight lifters, and that after 45 minutes cortisol levels rose, we MUST consider also that maybe these people were not using powerlifting techniques. Maybe if they were using power lifting techniques, it would have taken 2 hours for the cortisol to kick in (longer session, since more rests between sets). Or, maybe that's not the case, and that 45 minutes is a magic number in most all situations, no matter what.
I'd like to know more about cortisol...I don't want to just accept this 45 minute rule until I know more details.
These are 3 great places to find studies...I'll take a look because I'm kinda interested too!
Journal of Applied Physiology
Medicine & Science in Sports
here is a good one (although slightly off topic)
C= cortisol, T=testosterone
Pre-exercise C concentrations were significantly lower (p < 0.05) in the PM session, which resulted in a lower peak value, and the accompanying increased T/C ratio suggested a reduced catabolic environment.
These data demonstrate that the exercise-induced hormonal profile can be influenced by the circadian time structure toward a profile more favorable for anabolism, therefore optimizing skeletal muscle hypertrophic adaptations associated with resistance exercise.
Last edited by geoffgarcia; 06-07-2004 at 04:22 PM.
A bit unrelated, but:
"Influence of carbohydrate ingestion on immune changes after 2 h of intensive resistance training
D. C. Nieman,1 J. M. Davis,2 V. A. Brown,1 D. A. Henson,1 C. L. Dumke,1 A. C. Utter,1 D. M. Vinci,1 M. F. Downs,1 J. C. Smith,1 J. Carson,2 A. Brown,2 S. R. McAnulty,1 and L. S. McAnulty1
1Departments of Health, Leisure, and Exercise Science, Biology, Family and Consumer Sciences, Fischer Hamilton/Nycom Biochemistry Laboratory, Appalachian State University, Boone, North Carolina 28608; and 2Department of Exercise Science, University of South Carolina, Columbia, South Carolina 29208
Submitted 1 October 2003 ; accepted in final form 2 December 2003
Thirty strength-trained subjects were randomized to carbohydrate (CHO) or placebo (Pla) groups and lifted weights for 2 h (10 exercises, 4 sets each, 10 repetitions, with 2- to 3-min rest intervals). Subjects received 10 ml·kg-1·h-1 CHO (6%) or Pla beverages during the weight training bout. Blood, saliva, and vastus lateralis muscle biopsy samples were collected before and after exercise. Blood cell counts were determined, and plasma was analyzed for IL-6, IL-10, IL-1 receptor antagonist (IL-1ra), IL-8, and cortisol. Muscle was analyzed for glycogen content and relative gene expression of 13 cytokines (IL-1, IL-1, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12p35, IL- 12p40, IL-15, IFN-, TNF-) by use of real-time quantitative RT-PCR. Significant but modest increases were measured for plasma IL-6, IL-10, IL-1ra, and IL-8, but the pattern of increase did not differ between CHO and Pla groups. The rate of decrease in muscle glycogen content did not differ between CHO and Pla (P = 0.463). Muscle cytokine mRNA was detected preexercise for IL-1, IL-6, IL-15, IL-8, and TNF-, and of these, IL-1, IL-6, IL-8, and TNF- were significantly increased after the 2-h weight training bout. The increase in mRNA (fold difference from preexercise) did not differ between CHO and Pla groups. In summary, CHO vs. Pla ingestion did not alter modest increases measured for plasma IL-6, IL-10, IL-1ra, and IL-8, and muscle gene expression for IL-1, IL-6, IL-8, and TNF- in strength-trained subjects lifting weights intensively for 2 h.
cytokines; gene expression; muscle glycogen; real-time quantitative reverse transcription polymerase chain reaction"
So cortisol seems to be unaffected when carbohydrate was ingested during the weightlifting. But what about protein, and what about the type of carbohydrate. I know glucose and glycerin get to you fast, whereas something like sugar or bread, or juice doesn't get in as fast. Too many variables to test out.
"Pituitary-adrenal-gonadal responses to high-intensity resistance exercise overtraining
A. C. Fry1, W. J. Kraemer2, and L. T. Ramsey1
1 Human Performance Laboratories, University of Memphis, Memphis, Tennessee 38152; and 2 Center for Sports Medicine, Pennsylvania State University, University Park, Pennsylvania 16802
Weight-trained men [OT ; n = 11; age = 22.0 ± 0.9 (SE) yr] resistance trained daily at 100% one-repetition maximum (1-RM) intensity for 2 wk, resulting in 1-RM strength decrements and in an overtrained state. A control group (Con; n = 6; age = 23.7 ± 2.4 yr) trained 1 day/wk at a low relative intensity (50% 1 RM). After 2 wk, the OT group exhibited slightly increased exercise-induced testosterone (preexercise = 26.5 ± 1.3 nmol/l, postexercise = 29.1 ± 5.9 nmol/l) and testosterone-to-cortisol ratio (preexercise = 0.049 ± 0.007 nmol/l, postexercise = 0.061 ± 0.006 nmol/l) and decreased exercise-induced cortisol (preexercise = 656.1 ± 98.1 nmol/l, postexercise = 503.1 ± 39.7 nmol/l). Serum concentrations for growth hormone and plasma peptide F [preproenkephalin (107140)] were similar for both groups throughout the overtraining period. This hormonal profile is distinctly different from what has been previously reported for other types of overtraining, indicating that high-relative-intensity resistance exercise overtraining may not be successfully monitered via circulating testosterone and cortisol. Unlike overtraining conditions with endurance athletes, altered resting concentrations of pituitary, adrenal, or gonadal hormones were not evident, and exercise-induced concentrations were only modestly affected.
muscular strength; testosterone; cortisol; growth hormone; peptide F "
This test, from my understanding, seems to indicate that endurance athletes are easier people to study than high resistance people, because the levels of floating testosterone and cortisol in the blood is not a good indicator overtraining. It seems overtrained athletes were actually increasing their hormones in the blood, rather than decreasing.
They do not define what exactly overtraining really was though. I suppose they trained when they were sore, or they trained every day rather than resting.