Anabolic hormonal responses are integral in the regulation of tissue growth and energy substrate metabolism and therefore are thought to play an important role in building muscle as a response to high-intensity resistance exercise.[1] Plasma concentrations of circulating anabolic hormones such as growth hormone (GH), testosterone, and IGF-1 are each thought to play a prominent role regarding changes in strength and muscle mass.[2]

GH is shown to stimulate protein synthesis in humans [3]. Both cross-sectional and longitudinal studies [4-7] have shown that (serum total and free) testosterone concentrations, in particular, are, important regulators of net myoprotein balance. It’s interesting to note that muscle hypertrophy is shown to be proportional to increases in circulating testosterone concentrations, even in the absence of training [8]. However, the hormonal responses to a workout or workouts and the contribution these alterations make to training-induced changes in muscle growth are anything but unclear.

The acute increase in circulating anabolic hormones that are observed in response to training are not gender specific — although responses are typically higher in men than women.[9] Interestingly, the magnitude of these acute increases are independent of the individual’s absolute level of strength, and responses can vary widely among individualsboth novice and advanced trainers. [10]

Building Muscle – How many sets and how many reps?

The discussion regarding the manipulation of training variables to “optimize” the anabolic hormone response, such as the amount of load used, volume (number of sets and reps), etc., is a subject of great interest and confusion among bodybuilders and experts alike. For example, high loads and low volume are often prescribed as “best” to optimize testosterone responses [11,12] other studies suggest lighter weights with more reps promotes a better GH response [13,14]. Even exercise selection [13,14,15] have also been shown to influence the magnitude of the acute hormonal response to a workout.

However, keep this in mind; of all the hundreds of studies that have assessed hormonal responses to various workouts; very few have utilized relevant, real-life situations. For example, most studies assess anabolic hormone responses to training in an overnight-fasted state with no nutrient intake for up to 6 hours after training. What bodybuilder trains and doesn’t eat or supplement for 6-12 hours before and after a workout? How relevant is any data obtained under these conditions?

Additionally, it’s important to note that none of these studies involving different reps and sets have been able to link short-term hormone responses with changes in strength or muscle mass.

Therefore, based on these two rather important insights, it would seem as though any “research-based” arguments for various rep ranges and volume to “optimize” anabolic hormonal responses are irrelevant.

So next time you hear some “guru” proclaim that x amount of sets of x amount of reps is “best” for testosterone or GH response based on some study; you’ll know the information cited (if any) is probably useless.

A training program doesn’t appear to alter resting GH or testosterone concentrations. [17] Other research suggests that training may improve the anabolic hormonal response to a workout. That is, higher levels of GH and testosterone and lower cortisol concentrations have been observed in trained as opposed to untrained individuals after a workout.[18-20]

It is clear that the hypertrophic response is specific to the loaded muscle(s). [12] Therefore, activation by a systemic hormone would require load-mediated modulation of the hormone’s efficacy in the exercised muscle. The load-mediated modulation of receptor expression and binding affinity in muscle has been demonstrated in rodents and humans during training.[22,23]  This may explain localization of the growth response to elevated blood anabolic hormones. In healthy humans, at least one study has shown that sequential bouts of heavy training increased blood testosterone concentrations and muscle androgen receptor expression that correspond to subsequent increases in myofibrillar protein.[23]

What about nutrition?

Very few studies have examined the effects of nutrition intake on training-induced hormonal response patterns. This is somewhat bemusing and disappointing given numerous studies that have assessed endocrine responses to workouts and the important role that hormones play in the regulation of gene expression and protein metabolism.

In point form here’s what we know about nutrition influences regarding acute hormonal (and associated immune) responses in relation to muscle gains.

Nutrient Timing

VP2 Whey Isolate Vanilla - Best Whey ProteinSupplementation with protein and carbs before and after resistance training promotes higher blood insulin levels in the hour after exercise. Higher insulin levels at this time improves the anabolic response by increasing the uptake of amino acids and glucose while decreasing protein breakdown.

Most studies suggest that nutrient-timing enhances acute serum GH responses after exercise. [22,24]  This benefit also appears to carry over to circulating IGF-1 levelsboth after a workout and training programs.[27,28]

Nutrient timing appears to have a big impact on testosterone levels but not in the way that most bodybuilders would expect.

Nutrient-timing consistently promotes an increase in circulating testosterone followed by a sharp decrease, sometimes to levels significantly lower than baseline. [22,24, 29] This finding is directly opposite to studies that did not involve nutrient intake.

Micronized Creatine 1000 - Best Muscle-Building CreatineBefore you go throwing your supplements in the trash can, understand that this supplement-induced decline in circulating testosterone is due to increase metabolic clearance of this hormone. An increased uptake by muscle. [24, 30].

Therefore, strategic supplementation before and after workouts appears to enhance testosterone delivery into the muscle. This increased uptake by muscle may be one reason why I’ve seen 100% better gains in my clinical research on nutrient-timing with the combination of VP2 Whey Isolate, Micronized Creatine, and DGC.[31]

A lot of athletes fear carbohydrates more than death and taxes, but this fear couldn’t be more wrong. Strategic carbohydrate consumption before and after high-overload training may be the most potent anabolic-activator of all. And no other research has shown more significant gains in lean muscle than with the combination of VP2 Whey Isolate, Micronized Creatine, and DGC.[31]

DGC - Fast Muscle Energy and Hydration - Best Energy Carbohydrate SupplementExercise causes numerous changes in immunity that reflect physiological stress and immune-suppression. Carb supplementation before, during and after a workout lowers cortisol production and markers of inflammation. [32] As least one resistance training study has shown this strategy will blunt the cortisol response to high-overload training and provided better muscle hypertrophy. [26]

See Also:
Should I cycle creatine? If so, can you tell me the best way to do this?

So there you have it – about 30 years of research on the most pertinent aspects of hormonal responses to training and their effects on muscle gains. Limited research has linked training-induced hormone alterations to chronic adaptations such as strength or hypertrophy. However, we do know that if you’re concerned with building muscle, nutrient-timing appears to be a critical link that sets the hormone profile for much better gains.


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Adaptations and Influences That Affect Muscle Growth – Part-4 Hormone Responses

by Paul Cribb Ph.D. CSCS. time to read: 10 min