|Controlled exhaustion = positive adaptation; continuous exhaustion = wear and tear = one out of 57,002 who suffer from cardiac arrest during a marathon (data based on Webner. 2012)|
- two studies on heart health,
- one on wound healing and the last one on the
- bullet proof endogenous anti-oxidant system of trained athletes,
I know that does not sound as sexy as being big and buffed, but what's the use of that if you don't fit the coffin, you're about to need, when your looks are more important to you than your health?
IGF-Response to exercise implicated in "athletes heart" A group of polish researchers describes in their latest paper that's been published ahead of print in the International Journal of Sports Medicine, how the differential IGF-1 response to eccentric (ECC) and concentric (CON) arm exercise in 10 trained strength athletes (1.5-2.0 h on 3-5 days weekly) and 10 age-matched healthy non-trained subjects could explain the differences in the degree of left ventricular hypertrophy, the scientists had measure via M-mode and 2D Doppler echocardiography beforehand (Zebrowska. 2012).
|IGF1 and left ventricular hypertrophy (LVH): The correlation stands out of question, but what about the implications? Is this a causative relationship? And what's more: How dangerous are LVH and having an athlete's heart, at all?|
Moreover, we should acknowledge that the previously accepted paradigm that LVH, per se, is a bad thing that has to be avoided at all costs is actually not supported by empirical evidence, or as Florescu et al. have it "'Supranormal' cardiac function in athletes is due to better endothelial and arterial function, related to lower oxidative stress, with optimized ventriculo-arterial coupling; athlete's heart is purely a physiological phenomenon, associated with 'supranormal' cardiac function, and there are no markers of myocardial fibrosis." (Florescu. 2010)... in short: in the absence of myocardial fibrosis, a big heart is nothing you will die from - how IGF-1 could actually prevent the latter, i.e. the occurrence of fibrotic structures due to uncompensated growth of the heart muscle, would yet be the topic for another quite lengthy blogpost ;-)
- MIIT - moderate intensity interval training consisting of 10s : 20s cycles at 120% of the pretraining max. workrate : 20W for 30, 35 and 40min (bi-weekly progression), or
- HIIT - high intensity interval training consisting of 30s : 60s cycles at 120% of the pretraining max. workrate : 20W for 30, 35 and 40min (bi-weekly progression),
Trainees who want to increase their VO2max should still do HIIT, because only the subjects in the HIIT training group achieved statistically significant increases with respect to this outcome measure (+14% in HIIT vs. +3% VO2 max in MIIT).Just as the scientists had speculated, their hypothesis that irrespective of the metabolic stress, which would be higher in the HIIT vs. the MIIT trial, the total volume, which was identical would determine the overall adaptive response. For them it was therefore not surprising that all measured parameters of heart health, i.e.blood pressure, heart rate dynamics and carotid arterial stiffness, improved without significant inter-group differences. Most notably, though, those with the highest arterial stiffness before the trial saw the greatest reductions!
|Figure 2: Additional exercise sped up the wound healing process only in the obese rodents, not the lean ones (Pence. 2012)|
"the first report of an exercise effect on wound healing that is unrelated to alterations in wound site inflammation." (Pence. 2012)Future trials will have to elucidate whether clotting and homeostasis, which occur in the earliest stage of wound healing, approximately 30 min after the trauma may be involved in this phenomenon.
In this context, some of you will probably remember my recent post on the "Antithrombotic effects of caffeine blunt platelet activity in response to interval training" that exercise increases the tendency of your blood to clot - a tendency that does obviously come handy, when you are bleeding. That the increase in coagulation factors came into effect only in the obese, yet not in the normal weight control, in turn, could be related to the presence of existing hemostastic imbalances due to obesity which would have been corrected by the 30min of treadmill running the rodents in the exercise groups performed at a pace of 12 m/min on a 5% incline for the final 30 min of the light period (0930–1000 h), three days before until five days after the wounding.
|A bunch of maggots on a diabetic wound.|
|"Rust proof" athletes don't need vitamin pills with copious amounts of anti-oxidants and don't have to be afraid of fruit with their synergistic blend of small, but highly effective and synergistic amounts of vitamins and polyphenols, either.|
That's at least my allegedly nonchalant interpretation of the non-existent increases in serum markers of oxidation the scientists from the University of Memphis observed in their 12 male subjects (BMI 25kg/m², body fat 12.8%; VO2Max 20 ml/kg/min) in response to four training sessions separated by 1 wk.
The Sessions were counterbalanced and included either a no-exercise condition (subjects simply rested for the entire period) or one of the these three:
- MISS - moderate intensity + duration steady state: 70% HR reserve for 60min; total time: 60min with 60min of actual work
- HIIT - high intensity + moderate duration interval sprints: 5x60s at 100% + 225s recovery yielding a 1:3.75 work-to-rest ratio ("Within each interval, subjects were instructed to pedal between 80 and 100 rpm for the first 45 s, and then for the final 15 s, subjects were instructed to pedal as fast as possible"); total time: 20 min with 300s of actual work
- MaxIIT - maximal intensity + short duration interval: 10x15s at a wattage of 200% of VO2max, followed by 116s of recovery (1:7.7 work-to-rest ratio); total time: 20 min with 150s of actual work
|Figure 3: Total antioxidant capacity (TEAC), SOD, CAT and GPx values immediately (0min), 30min and 60min after the respective exercise bouts (data based on Farney. 2012)|
The respective total work performed during the trials was 461.1kJ, 96.9kJ, 96.9kJ for the MISS, HIIT and MaxIIT trials, respectively, the perceived exertion was highest in the MaxIIT trial (16.7 vs. 15.6 for HIIT and 13.5 for MISS), while the maximal heart rate 171.7bpm was achieved in the HIIT trial. Still,
"No differences were noted in malondialdehyde, H2O2, advanced oxidation protein product, or NOx between conditions or across time (P > 0.05) [while the a]ntioxidant capacity was generally highest at 30 and 60 min after exercise and lowest at 0 min after exercise." (Farney. 2012; my emphases)If you will, you could even go one step further and argue that the total antioxidant capacity increases in well-rested, well conditioned athletes in response to exhaustive exercise bouts. Though, this increase reaches statistical significance in the MaxIIT trial only (see figure 3).
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- Farney TM, McCarthy CG, Canale RE, Schilling BK, Whitehead PN, Bloomer RJ. Absence of blood oxidative stress in trained men after strenuous exercise. Med Sci Sports Exerc. 2012 Oct;44(10):1855-63.
- Pence BD, Dipietro LA, Woods JA. Exercise Speeds Cutaneous Wound Healing in High-Fat Diet-Induced Obese Mice. Med Sci Sports Exerc. 2012 Oct;44(10):1846-1854.
- Rakobowchuk M, Harris E, Taylor A, Cubbon RM, Birch KM. Moderate and heavy metabolic stress interval training improve arterial stiffness and heart rate dynamics in humans. Eur J Appl Physiol. 2012 Sep 16.
- Turner AP, Cathcart AJ, Parker ME, Butterworth C, Wilson J, Ward SA (2006) Oxygen uptake and muscle desaturation kinetics during intermittent cycling. Med Sci Sports Exerc 38:492–503.
- Webner D, Duprey KM, Drezner JA, Cronholm P, Roberts WO. Sudden cardiac arrest and death in United States marathons. Med Sci Sports Exerc. 2012 Oct;44(10):1843-5.
- Zebrowska A, Waśkiewicz Z, Zając A, Gąsior Z, Galbo H, Langfort J. IGF-1 Response to Arm Exercise with Eccentric and Concentric Muscle Contractions in Resistance-Trained Athletes with Left Ventricular Hypertrophy. Int J Sports Med. 2012 Sep 7.