I came across a interesting study that found growth hormone secretions to be 450% higher after 30s sprint verse 6 sprint. Heres the abstract.
The time course of the human growth hormone response to a 6 s and a 30 s cycle ergometer sprint.
Stokes KA, Nevill ME, Hall GM, Lakomy HK.
Department of Physical Education, Sports Science and Recreation Management, Loughborough University, UK.
Exercise is a potent stimulus for the release of human growth hormone (hGH), but the time course of the hGH response to sprint exercise has not been studied. The aim of the present study was to determine the time course of the hGH response to a 6 s and a 30 s maximal sprint on a cycle ergometer. Nine males completed two trials, on one occasion performing a single 6 s sprint and on another a single 30 s sprint. They then rested on a couch for 4 h while blood samples were obtained. Three of the participants completed a further control trial involving no exercise. Metabolic responses were greater after the 30 s sprint than after the 6 s sprint. The highest measured mean serum hGH concentrations after the 30 s sprint were more than 450% greater than after the 6 s sprint (18.5 +/- 3.1 vs 4.0 +/- 1.5 microg l(-1), P < 0.05). Serum hGH also remained elevated for 90-120 min after the 30 s sprint compared with approximately 60 min after the 6 s sprint. There was a large inter-individual variation in the hGH response to the 30 s sprint. In the control trial, serum hGH concentrations were not elevated above baseline at any time. It would appear that the duration of a bout of maximal sprint exercise determines the magnitude of the hGH response, although the mechanism for this is still unclear.
Acute hormonal responses to two different fatiguing heavy-resistance protocols in male athletes.
Häkkinen K, Pakarinen A
J Appl Physiol 1993 Feb 74:882-7
J Appl Physiol • Volume 74 • Issue 2
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MEDLINE, full MEDLINE, related records
Abstract
To examine endogenous hormonal responses to heavy-resistance exercise, ten male strength athletes performed two fatiguing but different types of sessions on separate days. In session A the loads for the leg extensor muscles in the squat-lift exercise were maximal so that the subjects performed 20 sets at 1 repetition maximum (RM) (20 x 1 RM x 100%), whereas during session B the loads were submaximal (70%) but the subjects performed each of the 10 sets until the RM (i.e., 10 repetitions/set or 10 x 10 x 70%). The recovery time between the sets was always 3 min. A decrease of 10.3 +/- 4.7% (P < 0.001) occurred in the squat-lift in 1 RM during session A, whereas session B led to a decrease of 24.6 +/- 18.9% (P < 0.001) in 10 RM. Increases in the concentrations of serum total and free testosterone (P < 0.05 and 0.05, respectively), cortisol (P < 0.001), and growth hormone (GH, P < 0.001) were observed during session B, whereas the corresponding changes during session A were statistically insignificant except for the relatively slight increase (P < 0.01) in serum GH level. The significant (P < 0.001) increase in blood lactate concentration during the two sessions correlated significantly (P < 0.01) with the increase in serum GH concentration. The morning values of serum testosterone and free testosterone were significantly (P < 0.05-0.001) lowered on the 1st and 2nd rest days after the sessions.
This is why a short to long program works for peaking…as you get faster and better at speed endurance, the GH response increases making you nice an lean (Herb would say fighting weight) for the big meets. I would not focus on GH response but realize that a great program (not just a workout) will make sure you have great hormone responses and endocrine levels.
Eur J Appl Physiol. 2004 Jun;92(1-2):26-32. Epub 2004 Feb 17.
Effect of 6 weeks of sprint training on growth hormone responses to sprinting.
Stokes KA, Nevill ME, Cherry PW, Lakomy HK, Hall GM.
Department of Sport and Exercise Science, University of Bath, BA2 7AY, Bath, UK. K.Stokes@bath.ac.uk
This study examined the effect of 6 weeks of prescribed sprint training on the human growth hormone (hGH) response to cycle ergometer sprinting. Sixteen male subjects were randomly assigned to a training (n=8) or a control (n=8) group. Each subject completed two main trials, consisting of two all-out 30-s cycle-ergometer sprints separated by 60 min of passive recovery, once before, and once after a 6-week training period. The training group completed three supervised sprint-training sessions per week in addition to their normal activity, whilst control subjects continued with their normal activity. In the training group, peak and mean power increased post-training by 6% (P<0.05) and 5% (P<0.05), respectively. Post-exercise blood pH did not change following training, but the highest post-exercise blood lactate concentrations were greater [highest measured value: 13.3 (1.0) vs 15.0 (1.1) mmol l(-1)], with lower blood lactate concentrations for the remainder of the recovery period (P<0.05). Post-exercise plasma ammonia concentrations were lower after training [mean highest measured value: 184.1 (9.8) vs 139.0 (11.7) micromol l(-1), P<0.05]. Resting serum hGH concentrations did not change following training, but the peak values measured post-exercise decreased by over 40% in the training group [10.3 (3.1) vs 5.8 (2.5) microg l(-1), P<0.05], and mean integrated serum hGH concentrations were 55% lower after training [567 (158) vs 256 (121) min microg l(-1), P<0.05]. The hGH response to the second sprint was attenuated similarly before and after training. This study showed that 6 weeks of combined speed- and speed-endurance training blunted the human growth hormone response to sprint exercise, despite an improvement in sprint performance.
The subjects here where healthy male volunteers, aged 21 to 32 yr.
J Appl Physiol. 2002 Feb;92(2):602-8.
Growth hormone responses to repeated maximal cycle ergometer exercise at different pedaling rates.
Stokes KA, Nevill ME, Hall GM, Lakomy HK.
Department of Physical Education, Sports Science and Recreation Management, Loughborough University, Loughborough, Leicestershire LE11 3TU, United Kingdom.
The present study examined the growth hormone (GH) response to repeated bouts of maximal sprint cycling and the effect of cycling at different pedaling rates on postexercise serum GH concentrations. Ten male subjects completed two 30-s sprints, separated by 1 h of passive recovery on two occasions, against an applied resistance equal to 7.5% (fast trial) and 10% (slow trial) of their body mass, respectively. Blood samples were obtained at rest, between the two sprints, and for 1 h after the second sprint. Peak and mean pedal revolutions were greater in the fast than the slow trial, but there were no differences in peak or mean power output. Blood lactate and blood pH responses did not differ between trials or sprints. The first sprint in each trial elicited a serum GH response (fast: 40.8 +/- 8.2 mU/l, slow: 20.8 +/- 6.1 mU/l), and serum GH was still elevated 60 min after the first sprint. The second sprint in each trial did not elicit a serum GH response (sprint 1 vs. sprint 2, P < 0.05). There was a trend for serum GH concentrations to be greater in the fast trial (mean GH area under the curve after sprint 1 vs. after sprint 2: 1,697 +/- 367 vs. 933 +/- 306 min x mU(-1) x l(-1); P = 0.05). Repeated sprint cycling results in an attenuation of the GH response.
What effects do GH have on our bodies?? Clemson mentioned it helps make us leaner. How is this?? Also I would assume GH has something to do with muscle growth. So if this is the case would running long sprints make us bigger?? I mean from observation, as the sprints get longer the athletes look less and less bulky with longer muscles. Can anyone shed some light here. Im going to be starting Speed Endurance soon and def cant afford to put on any weight(5’11" 210lbs). In fact ideally Id like to drop abt 15-20lbs.
*Note I’m referring to natural growth hormone release from the pituitary - not the use of GH from external sources (banned substsances).
It’s hard to explain but basically GH can either be anabolic or catabolic. When nutrient intake is high, GH secretion is increased leading also to increased levels of IGF-1, IGFBP3 and insulin. The main role of GH under these conditions is to increase anabolism through local growth factors like IGF-1 and insulin.
Conversely, when nutrient intake is low, GH is again increased. But this time there is no concomitant increase in IGF-1, IGFBP3, or insulin. Under these circumstances GH is acting as a catabolic hormone increasing the utilization of fat for fuel thus sparing body glucose yet having no muscle building effects.
In both cases fat loss can occur - though the increased metabolism of increased muscle, or through the use of fat as fuel.
Your weight gain or loss is going to be more influenced by your caloric intake and your macronutrient ratios than your exercise induced GH release. You also have to remember that GH has a negative feedback response to it’s own release, making it even less likely that you gain huge amounts of muscle or lose huge amounts of fat on your own natural GH release.
