ES 473- endocrine responses to resistance training

definition of stressor

any real or perceived internal or external action that induces a physiological consequence

Hans Selye theory of stress

-stress is a generalizable, universal physiological response

-body responds to all types of stress in the same way

the _______ and ______ of stress is ________ to its recovery

-magnitude and duration

-proportional

downregulation definition

the inability of a hormone to interact effectively with a receptor (less receptive)

down-regulation example

catecholamine receptor downregulation due to pregame excitement

mechanisms contributing to peripheral blood concentrations of hormones

circadian rhythms (pulsatile nature of some hormones), fluid volume shifts, tissue clearance rates, venous pooling of blood, hormone interactions with binding proteins, receptor status

hormones are intimately involved with ________ (catabolic) and _________ (anabolic) mechanisms

-degradation

-protein synthesis

anabolic pathways

-hypothalamus-pituitary-gonad(HPG) axis

-hypothalamus-pituitary-liver (HPL) axis

the HPG axis primarily involves

testosterone

the HPL axis primarily involves

growth hormone (GH) and insulin-like-growth-factor-1 (IGF-1)

catabolic pathways

-sympatho-adrenal-medullary (SAM) axis

-hypothalamus-pituitary-adrenal (HPA) axis

the SAM axis primarily deals with

catecholamines

the HPA axis primarily involves

cortisol

characteristics of testosterone

-primary anabolic hormone for skeletal muscle

-promotes GH and IGF-1--> synergistic effect on protein synthesis

-influences neuron adaptations

where do women produce testosterone?

in ovaries and adrenal glands

effects of testosterone (from diagram)

-anti-inflammatory effect

-increase in insulin sensitivity

-improved baroreceptor sensitivity

-improved muscle perfusion

exercise variables that increase testosterone

-large muscle group exercises (stress on full body)

-heavy loads (85-95% 1RM)

-moderate to high volume with multiple sets

-short rest periods (30-60 sec)

-two or more years of resistance training experience

what can acutely increase free testosterone in men and women?

heavy resistance exercise (6x10 reps at 80% 1RM)

hormone responses are tightly linked to ___________

the characteristics of the resistance exercise protocol

what stimulates receptor and membrane sensitivities to anabolic factors?

specific force produced

-leads to muscle growth and strength changes

anabolic factors will only occur in ____________

tissues activated by exercise

unrecruited fibers will have a ________ effect

catabolic

hypothalamus-pituitary-liver (HPL) axis primary hormone and functions

-growth hormone

-increases lipolysis

-decreases glucose utilization

additional functions of the HPL axis

-increases collagen synthesis

-increases cartilage growth

-stimulates release of IGF-1 and mTOR

-increases protein synthesis

-increases immune function

GH is more crucial for ________ and IGF-1 is more crucial for ___________

-child development

-resistance training adaptation

GH release is correlated with _______

-metabolic stress (pH drop, lactate)

exercise variables that increase GH secretion

-whole body, high volume (at least 3x10 rm)

-<1 min rest

what dietary supplementation can stimulate IGF-1 and when?

carbohydrates and proteins before and after exercise

insulin is a primarily ________ hormone

anabolic

resistance and aerobic training increase insulin ___________

sensitivity

when is insulin secreted? what is essential to optimize insulin release?

-when blood glucose is raised (carb consumption)

-post-exercise nutrition

insulin effects:

-increases protein synthesis and decreases protein degradation

-increases amino acid uptake

-replenishes glycogen stores (glycogenesis)

mTOR is the primary ______________. it is simulated by _______ ,_________, and ________ stimuli

-anabolic cell signaling pathway

-mechanical, hormonal, nutritional (leucine)

nutrition recommendations 0-2 hours post resistance exercise

-1.5 g/kg CHO

-0.3 g/kg PRO

-10 g essential amino acids (leucine, isoleucine)

-electrolytes and fluid

nutrition recommendations 0-2 hours post endurance exercise

-1.5 g/kg (immediately) and 1.2 g/kg thereafter CHO

-10 g PRO

-electrolytes and fluid

resistance training recommendations for increasing muscle protein synthesis

-multiple sets to failure

-high load and low load can enhance MPS

catabolic effects of cortisol (HPA axis)

-gluconeogenesis, decrease glycogenesis, decrease insulin sensitivity

-increase fat mobilization

-decrease immune and inflammatory function

-regulates blood pressure

cortisol competes with _______ for nuclear receptor signaling, leading to ___________

-testosterone

-decreased protein synthesis (why the full motor unit recruitment is important)

cortisol has a greater effect on what type of muscle fibers?

type II

highest increase of cortisol with what type of volume-load? (resistance training)

high volume-load and low rest periods

-same stimuli as GH

what kind of cortisol increases can be beneficial and why?

-acute (within sessions)

-sustains blood glucose and may help muscle fiber remodeling

effects of chronically high cortisol

-suppresses immune function (B + T cells)

-cardiometabolic issues

-overtraining biomarker >800 nmol/L

why is skeletal muscle cortisol receptor concentration lower after training

cortisol actions are inhibited at the testis

acute increases in cortisol contribute to _________ and _________, but chronic high concentrations have ________ effect

-tissue remodeling, blood glucose maintenance

-adverse catabolic

sympatho-adrenomedullary (SAM) axis primary hormones and functions

-catecholamines (epi and norepi)

-increase force production

-increase muscle contraction rate

-increase energy availability (glycogenesis, glycolysis)

-increase HR and BP

-increase muscle blood flow

-augment section rates of other hormones (testosterone)

an ____________ in epinephrine is beneficial to performance

anticipatory rise

highest increase of catecholamines with what kind of volume-load?

high volume load and low rest periods

which hormone is first secreted during resistance training?

epinephrine

what can be caused from a consistently high volume load? what are the adverse effects?

-prolonged adrenal gland activation

-delayed recovery, poor anabolism, potential NFOR or OTS

what are the epi responses after training (submax vs maximal exercise)?

-submax: lower epi release

-maximal: increases epi release

possible endocrine system adaptations from resistance training

-increased synthesis and storage of hormones

-altered time for hormone clearance

-increased receptor upregulation at tissues

-change in secretory cell contents in a gland

-altered degree of interaction with the cell nucleus

what generates the adaptive "voice" in the endocrine system?

interaction, redundancy, and regulation of various cell signals (endocrine, neural, nutrition, mechanical, metabolic)

what kind of resistance training workout promotes the highest GH increase?

-3x10 RM with 1 min rest

-high metabolic stress

what kind of resistance training workout promotes the highest testosterone increase?

-4x4 RM with 1 min rest

-high intensity, core lift, short rest