ch4 - endocrine responses to resistance exercise Flashcards
(143 cards)
1
Q
why was general adaptation syndrome coined?
A
to refer to how the adrenal gland responds to a noxious stimulus (stressor). this increase in resistance to the stress is referred to as adaptation; when the stressor is exercise, it is called training adaptation.
2
Q
what hormones are released from the anterior pituitary?
A
growth hormone, adrenocorticotropic hormone, beta endorphins, thyroid stimulating hormone, follicle stimulating hormone, luteinizing hormone, prolactin
3
Q
what hormones are released by the posterior pituitary?
A
antidiuretic hormone, oxytocin
4
Q
what hormones are released by the thyroid gland?
A
thyroxine, calcitonin
5
Q
what hormones are released by the parathyroid gland?
A
parathyroid hormone
6
Q
what hormones are released by the pancreas?
A
insulin, glucagon
7
Q
what hormones are released by the adrenal cortex?
A
Glucocorticoids (cortisol, cortisone, and so on), Mineralocorticoids (aldosterone, deoxycorticosterone, and so on)
8
Q
what hormones are released by the liver?
A
insulin-like growth factors
9
Q
what hormones are produced by the adrenal medulla?
A
epinephrine, norepinephrine, and proenkephalin fragments (e.g. peptide F)
10
Q
what hormones are produced by the ovaries?
A
estradiol and progesterone
11
Q
what hormones are produced by the testes?
A
testosterone
12
Q
what hormones are produced by the atrium of the heart?
A
atrial peptide
13
Q
what hormones are produced by the kidney?
A
renin
14
Q
what are the functions of growth hormone?
A
stimulates insulin-like growth factor I secretion from the liver, protein synthesis, growth, and metabolism; other aggregates of the growth hormone (GH) also have biological function and make up the more complex super family of GH.
15
Q
what are the functions of adrenocorticotropic hormone?
A
stimulates glucocorticoid secretion from the adrenal cortex
16
Q
what are the functions of beta-endorphin?
A
stimulates analgesia
17
Q
what are the functions of thyroid stimulating hormone?
A
Stimulates thyroid hormone secretion from the thyroid gland
18
Q
what are the functions of follicle-stimulating hormone?
A
Stimulates growth of follicles in ovary and seminiferous tubules in testes; stimulates ovum and sperm production
19
Q
what are the functions of luteinizing hormone?
A
Stimulates ovulation as well as secretion of sex hormones in the gonads (ovaries and testes)
20
Q
what are the functions of prolactin?
A
Stimulates milk production in mammary glands; maintains corpora lutea and secretion of progesterone
21
Q
what are the functions of antidiuretic hormone?
A
Increases contraction of smooth muscle and reabsorption of water by kidneys
22
Q
what are the functions of oxytocin?
A
Stimulates uterine contractions and release of milk by mammary glands
23
Q
what are the functions of thyroxine?
A
Stimulates oxidative metabolism in mitochondria and cell growth
24
Q
what are the functions of calcitonin?
A
Reduces calcium phosphate levels in blood
25
what are the functions of parathyroid hormone?
Increases blood calcium; decreases blood phosphate; stimulates bone formation
26
what are the functions of insulin?
Reduces blood glucose concentrations via promotion of glucose uptake by cells; promotes glycogen storage; suppresses fat oxidation and gluconeogenesis; is involved in protein synthesis
27
what are the functions of glucagon?
Increases blood glucose levels
28
what are the functions of glucocorticoids (cortisol, cortisone, and so on)?
Catabolic and anti-anabolic: promote protein breakdown and inhibit amino acid incorporation into proteins; conserve blood glucose concentrations via stimulation of conversion of proteins into carbohydrates (gluconeogenesis); suppress immune cell function; promote fat oxidation
29
what are the functions of mineralocorticoids (aldosterone, deoxycorticosterone, and so on)?
Increase body fluids via sodium-potassium retention
30
what are the functions of insulin-like growth factors
Increase protein synthesis in cells
31
what are the functions of epinephrine?
Increases cardiac output; increases blood sugar and glycogen breakdown and fat metabolism
32
what are the functions of norepinephrine?
Has properties of epinephrine; also constricts blood vessels
33
what are the functions of proenkephalin fragments (e.g., peptide F)?
Enhance immune cell function, have analgesia effects
34
what are the functions of estradiol?
Stimulate development of female sex characteristics
35
what are the functions of progesterone?
Stimulates development of female sex characteristics and mammary glands; maintains pregnancy
36
what are the functions of testosterone?
Anabolic and anticatabolic: promotes amino acid incorporation into proteins and inhibits protein breakdown; stimulates growth and development and maintenance of male sex characteristics
37
what are the functions of atrial peptide?
regulates sodium, potassium, and fluid volume
38
what are the functions of renin?
regulates kidney function, permeability, solute
39
by what mechanisms can hormones function?
via intracrine, autocrine, and paracrine mechanisms
40
what are the differences between intracrine and autocrine secretion?
intracrine and autocrine secretion of a hormone means that the cell releases the hormone to act upon the cell itself, via binding to intracellular and membrane receptors, respectively. It may be stimulated to do so via an external stimulus (e.g., another hormone), but the secreted hormone never enters the blood circulation.
41
what is an example of an autocrine/paracrine signaling?
insulin-like growth factor I (IGF-I) can be produced inside the muscle fiber when stimulated by mechanical force production or growth hormone(s) interactions with the muscle cell
42
what does paracrine secretion entail?
the release of a hormone to interact with adjacent cells, without moving into the blood circulation
43
what is a function of sex hormone-binding globulin (SHBG)?
can bind to specific membrane receptors and initiate activation of a cyclic adenosine monophosphate (cAMP) pathway
44
how limited are the tissue interactions of testosterone?
testosterone or one of its derivatives interacts with almost every tissue in the body.
45
what are the physiological roles of hormones?
regulation of reproduction; maintenance of the internal environment (homeostasis); energy production, utilization, and storage; and growth and development.
46
what does muscle remodeling involve?
the disruption and damage of muscle fibers, an inflammatory response, degradation of damaged proteins, hormonal and other signal (e.g., growth factors, cytokines) interactions, and ultimately the synthesis of new proteins and their orderly incorporation into existing or new sarcomeres
47
what does the inflammatory process involve?
the immune system and various immune cells (e.g., T and B cells), which are influenced by the endocrine system
48
how might cortisol have a negative effect on skeletal muscle through signaling pathways?
block other signaling pathways such as the Akt/mechanistic target of rapamycin (mTOR) pathway involved in mRNA translation initiation
49
is the binding sensitivity of receptors fixed?
no, receptors have the ability to increase or decrease their binding sensitivity, and the actual number of receptors present for binding can also be altered
50
how does exercise affect the binding sensitivity of testosterone?
it doesn't, it only affects the maximal number of receptors
51
for any steroid hormone, what is the first step leading to a biological effect?
after diffusing across the sarcolemma, the hormone binds with its receptor to form a hormone-receptor complex (H-RC), causing a conformational shift in the receptor and thus activating it
52
what is the second step after a hormone binds with its receptor and activates it?
it then binds to another H-RC and moves to the nucleus, where it arrives at the DNA. the H-RC "opens" the double-stranded DNA in order to expose transcriptional units that code for the synthesis of specific proteins
53
what is the next step in a steroid hormone's process toward biological effect after the H-RC "opens" the double-stranded DNA in order to expose transcriptional units?
the H-RC recognizes specific enhancers, or upstream regulatory elements of the specific gene promoted by the given hormone, and that specific part of the DNA is transcribed
54
what is the next step after the DNA is transcribed in the steroid hormone process toward biological effect?
the resultant messenger RNA (mRNA) then moves into the sarcoplasm of the cell, where it is translated by the ribosome into the specific protein promoted by the steroid hormone. With its interaction at the genetic level of the cell, the action of the steroid hormone is completed
55
what is the entire process of events leading to biological effect of a steroid hormone?
1. after diffusing across the sarcolemma, the hormone binds with its receptor to form a hormone-receptor complex (H-RC), causing a conformational shift in the receptor and thus activating it 2. it then binds to another H-RC and moves to the nucleus, where it arrives at the DNA. the H-RC "opens" the double-stranded DNA in order to expose transcriptional units that code for the synthesis of specific proteins 3. the H-RC recognizes specific enhancers, or upstream regulatory elements of the specific gene promoted by the given hormone, and that specific part of the DNA is transcribed 4. the resultant messenger RNA (mRNA) then moves into the sarcoplasm of the cell, where it is translated by the ribosome into the specific protein promoted by the steroid hormone. With its interaction at the genetic level of the cell, the action of the steroid hormone is completed
56
what is a caveat to the steroid hormone's mRNA production?
the fact that mRNA is produced for a specific protein (e.g., actin) does not necessarily mean that that protein is produced by the ribosome and incorporated into the sarcomere. the hormone message to produce a specific mRNA is only the first part of the entire process of protein synthesis.
57
are insulin and growth hormone steroid hormones?
no, they are polypeptide hormones
58
polypeptide hormones are not fat soluble. what are the implications of this?
they cannot cross the cell membrane
59
how do polypeptide hormones transmit hormonal signals if they cannot cross the cell membrane?
secondary messengers inside the cell are activated by the conformational change in the receptor induced by hormone binding; in this way, the membrane receptors transmit the hormonal signal to the inside of the cell where it propagates through a cascade of signaling events inside the cell
60
what do the signaling cascades initiated by polypeptide hormones affect?
metabolic processes, DNA transcription, and mRNA translation initiation at the ribosome
61
what are amine hormones synthesized from?
the amino acid tyrosine (e.g., epinephrine, norepinephrine, and dopamine) or tryptophan (e.g., serotonin)
62
how might hormones be secreted *before*, as opposed to during/after, an exercise bout?
due to the anticipatory response
63
how can hormone samples be measured?
from blood samples drawn from athletes at various stages of exercise and training; also in the fluid surrounding the muscle or within the muscle itself
64
do hormone concentrations in the blood indicate the status of receptor populations?
no, nor do they indicate the effects of a hormone within the cell, however it is assumed that large increases in hormone concentration indicate higher probabilities for interactions with receptors.
65
why are decreases in hormonal concentrations difficult to interpret?
might indicate higher uptake into the target tissue receptors, greater degradation of the hormone, decreased secretion of the hormone, or some combination of these
66
what physiological mechanisms contribute observed changes in peripheral blood concentrations of hormones with exercise?
circadian pattern, fluid volume shifts (exercise tends to push fluid from the blood to the intercellular compartment), tissue clearance rates (time spent in a tissue), venous pooling of blood, and hormone interactions with binding proteins
67
what kind of hormonal adaptations are possible with exercise?
1. Amount of synthesis and storage of hormones 2. Transport of hormones via binding proteins 3. Time needed for the clearance of hormones through liver and other tissues 4. Amount of hormonal degradation that takes place over a given period of time 5. How much blood-to-tissue fluid shift occurs with exercise stress 6. How tightly the hormone binds to its receptor (receptor affinity); this is an uncommon response to exercise training 7. How many receptors are in the tissue 8. The change in the content and in some cases the size of the secretory cells in the gland 9. The magnitude of the signal sent to the cell nucleus by the H-RC or secondary messenger 10. The degree of interaction with the cell nucleus (which dictates how much muscle protein to produce)
68
why are hormones secreted?
in response to a need for homeostatic control in the body
69
what do testosterone and DHT interact with?
testosterone -- skeletal muscle tissue. DHT -- sex-linked tissues (e.g. prostate)
70
how important is circulating testosterone for the anabolic signal?
important, but the binding of testosterone to its receptor is the key to stimulating anabolic functions, so an absolute increase in concentration is not a good marker of this
71
what is the relationship of testosterone and growth hormone?
testosterone can promote growth hormone release from the pituitary, and growth hormone appears to have a permissive or synergistic effect on testosterone's promotion of protein synthesis
72
how does testosterone influence the nervous system?
testosterone can interact with receptors on neurons, increase the amounts of neurotransmitters, and influence structural protein changes; each of these interactions can enhance the force production potential and mass of the innervated muscle
73
how is testosterone transported following secretion?
to target tissues by a binding protein (largely sex hormone-binding globulin and albumin); at the target tissue, testosterone disassociates from the binding protein and crosses the cell membrane in order to bind to the intracellular androgen receptor
74
what does binding to cell membrane receptors allow testosterone to do?
a rapid intracellular effect of testosterone, such as calcium release, to occur
75
variations in testosterone's cellular actions consequent to resistance exercise may be attributed to what?
differences in the cell membrane, perhaps because of the forces placed on membranes with resistance exercise, or to different feedback mechanisms sending signals to the higher brain centers (e.g., higher levels of testosterone feeding back on the brain to decrease luteinizing hormone secretion)
76
what would explain the increase in testosterone during high intensity aerobic exercise?
the need for protein synthesis to keep up with protein loss
77
if testosterone raises with high intensity aerobic exercise, is this sufficient for hypertrophy?
not typically because the cellular mechanisms for hypertrophy are not activated; in fact, oxidative stress may actually promote a decrease in muscle fiber size in order to optimize oxygen transport into the cell
78
can young boys induce hypertrophy?
generally no, because testosterone production in prepubescent boys is very low
79
what are the training factors that influence testosterone?
1. Large muscle group exercises (e.g., deadlift, power clean, squats) 2. Heavy resistance (85-95% of 1RM) 3. Moderate to high volume of exercise, achieved with multiple sets, multiple exercises, or both 4. Short rest intervals (30 seconds to 1 minute) 5. Two years or more of resistance training experience
80
how does time of day influence testosterone secretion?
to date, time of day of strength training (e.g., morning or afternoon) has not been shown to have significant effects on the resting total testosterone concentrations, its diurnal pattern, or the absolute increase in maximum strength
81
what is the silver lining of the lowered concentration of testosterone in women?
their androgen receptors is very dynamic with a much faster upregulation than in men, likely to better use the amount of testosterone present with a resistance exercise stimulus
82
what does it mean for testosterone to be "free"?
not bound to a binding protein, such as sex hormone-binding globulin for transport
83
what percent of total testosterone does free testosterone account for?
free testosterone accounts for only 0.5% to 2% of total testosterone; thus higher total testosterone concentration allows for more free testosterone.
84
how does age affect free testosterone response to resistance exercise?
younger (i.e., 30-year-old) men had higher concentrations of free testosterone after a workout than older (i.e., 62-year-old) men. this might indicate greater biological potential for testosterone to interact with the target tissues in younger men.
85
what is the free hormone hypothesis?
it is only the free hormone that interacts with target tissues.
86
how much lower testosterone do women have than men?
about 15- to 20-fold lower concentrations of circulating testosterone
87
why might aiming to raise testosterone concentrations with exercise be an outmoded concept?
after exercise, it may well be that other receptors on other target tissues (e.g., nervous, satellite cells) are more affected at certain time points in training depending on the window of adaptation available in the target tissues; still one might expect an increase in the exercise-induced concentrations due to improved functional capacity and the ability to do more work in an exercise protocol
88
where is the 22 kDa GH produced?
in the somatotroph of the anterior pituitary gland, in two types of somatotrophs, band 1 (containing smaller molecular weight forms, e.g., 22 kDa) and band 2 (containing large molecular weight forms such as aggregates).
89
why has the 22 kDa GH variant been overemphasized?
there is a much higher concentration of bioactive GH (i.e., aggregates) when compared to just the 22 kDa GH monomer; however, the majority of studies in exercise endocrinology have examined the 22 kDa isoform due to the ease and popularity of immunoassays (often termed radioimmunoassay [RIA], enzyme-linked immunosorbent assay [ELISA], or enzyme immunoassay [EIA]). These techniques depend on antibody interactions to determine the amount present in the blood. The antibodies used are generally specific to the 22 kDa GH variant, and thus many other forms remain undetected or underdetected with such assay techniques
90
what are the target tissues of GH?
bone, immune cells, skeletal muscle, fat cells, and liver tissue
91
what are the main roles of GH?
1. Decreases glucose utilization 2. Decreases glycogen synthesis 3. Increases amino acid transport across cell membranes 4. Increases protein synthesis 5. Increases utilization of fatty acids 6. Increases lipolysis (fat breakdown) 7. Increases availability of glucose and amino acids 8. Increases collagen synthesis 9. Stimulates cartilage growth 10. Increases retention of nitrogen, sodium, potassium, and phosphorus 11. Increases renal plasma flow and filtration 12. Promotes compensatory renal hypertrophy 13. Enhances immune cell function
92
autocrine signaling is what?
a form of cell signaling in which a cell secretes a hormone or chemical messenger (called the autocrine agent) that binds to autocrine receptors on that same cell, leading to changes in the cell; this can be contrasted with paracrine signaling, intracrine signaling, or classical endocrine signaling.
93
paracrine signaling is what?
a form of cell signaling or cell-to-cell communication in which a cell produces a signal to induce changes in nearby cells, altering the behaviour of those cells
94
endocrine signaling?
the endocrine system can be contrasted to both exocrine glands, which secrete hormones to the outside of the body using ducts and paracrine signalling between cells over a relatively short distance. Endocrine glands have no ducts, are vascular and commonly have intracellular vacuoles or granules that store their hormones. In contrast, exocrine glands, such as salivary glands, sweat glands, and glands within the gastrointestinal tract, tend to be much less vascular and have ducts or a hollow lumen.
95
what does 22 kDa GH stimulate?
the release of IGFs at the autocrine level of the cell, contributing to the overall changes in IGFs in the body, and increases the availability of amino acids for protein synthesis
96
is GH an anabolic hormone, or neutral?
yes, it plays a crucial role in direct cellular interactions as one of the most potent anabolic hormones
97
is the secretion of 22 kDa GH (including in blood) circadian-influenced?
yes and no; the highest levels are observed at night during sleep. however, the higher amounts of bioactive GH have not been shown to have a circadian pattern.
98
how might GH influence strength?
by directly influencing adaptations of the contractile unit of muscle and subsequent expressions of strength
99
what external factors alter GH release patterns?
age, male versus female sex, sleep, nutrition, alcohol consumption, exercise
100
what are the pituitary hormones and what do they respond to?
proopiomelanocortin [POMC], GHs, and prolactin; they respond to a variety of exercise stressors, including resistance exercise, and growth hormone (22 kDa) concentrations increase in response to breath holding and hyperventilation alone, as well as to hypoxia
101
what physiological stimulus (e.g. "elevation of ___ concentration") is connected to 22 kDa GH?
increased hydrogen ion (drop in pH) and lactate concentrations
102
can light loads stimulate 22 kDa GH?
not advisable; when light load (28% of 7RM) was used with a high number of repetitions in each set, no changes in the serum concentration of the 22 kDa GH occurred
103
why might intensity thresholds be essential to elicit significant 22 kDa GH?
possibly due to the metabolic connection with glycolytic metabolism
104
what factors affect 22 kDa GH response?
load, rest, exercise volume, and exercise selection
105
how does the menstrual cycle affect 22 kDa GH?
women have higher blood concentrations of the 22 kDa GH than men due to greater frequency and amplitude of secretion; ... during a heavy resistance exercise protocol characterized by long rest periods (3 minutes) and heavy loads (5RM), 22 kDa GH concentrations did not increase above resting concentrations, but they did significantly when a short-rest (1 minute) and moderate-resistance (10RM) exercise protocol was used
106
how does hormonal contraception (estrogen pill) affect GH?
appears to increase the 22 kDa GH response to resistance exercise
107
how do men and women differ in GH response?
the response patterns of men and women to the same resistance exercise protocol are similar when workouts are compared
108
what suggests the importance of higher aggregated forms of GH vs resting concentrations?
higher concentrations of bioactive GH are observed in women who have greater strength, and concentrations of bioactive GH are not as high in older women as in younger women, and resistance exercise is a more potent stimulus to bioactive GH than endurance exercise. meanwhile little change occurs in the 22kDa resting levels.
109
what modulates the effects of 22 kDa GH?
insulin-like growth factors (IGFs) aka somatomedins
110
how many amino acids do IGF1 and 2 have?
IGF-I is a 70 amino acid polypeptide, and IGF-II is a 67 amino acid polypeptide
111
Insulin-like growth factors travel in the blood bound to binding proteins; in the target tissue, IGFs disassociate from the binding
protein and interact with the receptors. Blood levels of IGFs are usually measured as either total levels (bound plus free) or free IGF concentrations.
112
what are the six different circulating binding proteins that regulate the amount of IGF available for receptor interaction?
IGF-I binding proteins 1 to 6, with binding protein-1 and binding protein-3 the most extensively studied in terms of their response to exercise. (each binding protein responds to exercise stress independently and has its own biological actions)
113
what autocrine function does IGF exert?
Insulin-like growth factor has been shown to stimulate the secretion of its own binding proteins from within the muscle cell itself, thus modulating the cell's responsiveness to IGF
114
how do IGF binding proteins play a role in anabolism?
in restricting access of the IGF peptides to receptors; they are influenced by 22 kDa GH concentrations
115
how do binding proteins help IGF?
binding proteins act as a reservoir of IGF, and release from the binding proteins is signaled by the availability of a receptor on the cell. this allows IGF to be viable for a longer period of time and could theoretically reduce the amount of degradation of IGF
116
what influences IGF-1 releasing mechanisms?
exercise stress; acute hormonal responses; the need for muscle, nerve, and bone tissue remodeling at the cellular level
117
what biocompartments does IGF-1 exist across?
blood, interstitial fluid [ISF], and muscle
118
how long does it take for IGF to be produced and released from the liver?
8 to 24 hours following stimulation by GH
119
what data indicate that exercise-induced increases in circulating IGF-1 are not reflective of local signaling?
in a study of men and women, it was shown that the increase in circulating total and free IGF-I was not correlated with increases in interstitial fluid IGF-I concentrations or muscle IGF-I protein content
120
what nutritive factors influence IGF?
acute caloric loads, which included carbohydrate and protein supplementation before and after a workout
121
what are the divisions of the adrenal gland?
the medulla (center) and the cortex (shell); both divisions respond to exercise stress.
122
how is the adrenal gland stimulated?
1. adrenal medulla is stimulated directly by the nervous system and thus provides a fast and almost immediate response; 2. the cortex is stimulated by adrenocorticotropic hormone (ACTH) released from the anterior pituitary.
123
what is peptide F?
an enkephalin-containing polypeptides from the adrenal medulla; it's a proenkephalin fragment that plays an important role in enhancing immune cell functions
124
what is cortisol a signaling hormone for?
cortisol is a primary signal hormone for carbohydrate metabolism and is related to the glycogen stores in the muscle (when glycogen concentrations are low, other substrates (proteins) must be catabolized to produce energy and to support maintenance of blood glucose concentrations)
125
does cortisol display a circadian pattern?
concentration is greatest in the early morning and drops throughout the day
126
how does cortisol exert catabolic effects?
by stimulating the conversion of amino acids to carbohydrates, increasing the level of proteolytic enzymes (enzymes that break down proteins), inhibiting protein synthesis, and suppressing many glucose-dependent processes such as glycogenesis and immune cell function
127
why might cortisol be more catabolic to type II fibers than type I?
they contain more protein than type I
128
how do type I and type II fibers differ in terms of hypertrophic mechanisms?
Type I fibers rely more on reducing degradation to develop muscle hypertrophy, in contrast to the dramatic increases in synthesis used by Type II fibers to develop hypertrophy
129
how does cortisol cause atrophy in conditions of disease, joint immobilization, or injury?
an elevation in cortisol mediates a nitrogen-wasting effect with a net loss of contractile protein
130
how do the effects of testosterone and insulin counter cortisol's catabolic effects?
if a greater number of receptors are bound with testosterone and this receptor complex then blocks the genetic element on the DNA to which cortisol and its receptor complex can bind, protein is conserved or enhanced. conversely, if a greater number of receptors are bound to cortisol, protein is degraded and lost.
131
when does cortisol increase with resistance exercise?
most dramatically when rest periods are short or the total volume of work is high; the highest catabolic responses in the body also produces the greatest GH response (this may be a muscle remodeling response)
132
what magnitude of cortisol increase is needed to indicate potential overtraining problems?
greater than 800 nmol/L
133
what is the predictive power of testosterone-to-cortisol ratio on anabolism?
weak; serum cortisol measurements and the testosterone-to-cortisol ratio have met with only limited success; the problems probably have to do with the multiple roles of cortisol and other hormones
134
how might cortisol differ in its response?
men and women respond differently with a 5RM protocol, indicating that target tissues might respond differently
135
what role of cortisol has a direct impact on recovery and skeletal tissue remodeling?
by suppressing function of cells of the immune system (e.g., B and T cells) -- this impact of cortisol on immune cells can be dramatic; the main effect "inactivates" immune cell functions, which partially contributes to the immune suppression observed after intense exercise stress
136
how does glucocorticoid receptor expression change with heavy exercise?
glucocorticoid receptor expression in B cells decreased with exercise and increased during recovery, demonstrating a greater binding, which in turn would reduce B cell activity during recovery (effects somewhat attenuated in women)
137
where are the catecholamines epinephrine norepinephrine and dopamine secreted and what is their function?
adrenal medulla, act as central motor stimulators and peripheral vascular dilators and enhance enzyme systems and calcium release in muscle
138
physiological functions of epinephrine and norephinephrine?
• Increase force production via central mechanisms and increased metabolic enzyme activity • Increase muscle contraction rate • Increase blood pressure • Increase energy availability • Increase muscle blood flow (via vasodilation) • Augment secretion rates of other hormones, such as testosterone
139
what kind of workout builds catecholamines in one study?
high-intensity (10RM), short-rest (10-60 seconds between sets and exercises), heavy resistance exercise routine (10 exercises, three sets)
140
what is the relationship with epinephrine and lactate concentration?
epinephrine has been correlated to lactate concentrations with exercise stress; adrenal responses are not involved in the recovery responses until the stress is removed
141
what critical recovery peptides, affecting the immune system, are secreted by the adrenal medulla?
endogenous opioid peptides (i.e., proenkephalins)
142
how does training variation help recovery wrt catecholamines?
if training is not varied, continued stress keeps the adrenal gland engaged, and recovery is delayed due to the secondary responses of cortisol and its negative effects on immune system cells and protein structures.
143
how should hormonal training for catecholamines be managed?
be careful to vary the training protocol and the rest period length from short to long over time, provide days of complete rest, and use lower-volume workouts to allow the adrenal gland to engage in recovery processes, to reduce stress on the adrenal medulla so as not to experience adrenergic exhaustion, and to reduce stress on the adrenal cortex and prevent chronic cortisol secretions from the adrenal cortex. This way, the stress of the exercises will not result in a nonfunctional overreaching or overtraining
