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In all cases, the cause of the problems is the gradual decline of availability of the most important hormone in the male body - testosterone. Note that we do not say "decline of levels of testosterone" - it is the availability of testosterone which is the problem. The average man who visits his doctor because he is losing the capacity to get erections is likely to be given medication - prescription medications like Viagra being favorite, with anticholesterol medication coming close behind. If his absolute testosterone levels are low, he may even be given (grudgingly) a chance to take hormone replacement - which very possibly will have no impact on his erections or sex drive, and will then be withdrawn on the grounds he may get prostate cancer!
Happily, a few doctors now advise testosterone therapy from an enlightened place, knowing that it is not just the absolute values of testosterone which indicate the bio-availability of the hormone.
Factors Which Affect Your Testosterone Levels
Testosterone, produced in large quantities during puberty and early adulthood, causes development of the secondary sexual characteristics such as axillary and pubic hair and affects the testosterone receptors in all body tissues. This means testosterone affects all organs and glands: it's effects are most obvious in the hair follicles, muscle cells, and maturation of the penis and testicles. Testosterone also has a role to play in such things as aggression, risk taking, and territoriality, and it also helps to mitigate depression.
Testosterone does not work alone, nor is it an entity in the body in isolation. The sequence begins with cholesterol, from which is produced pregnenolone, the “master hormone”; that is used by the body to manufacture dehydroepiandrosterone (DHEA; a precursor to testosterone); both testosterone and estrogen are produced from pregnenolone and DHEA. Dehydroepiandrosterone is the steroid found in highest concentrations in the male and female body. DHEA changes, and changes in enzymes that convert DHEA to testosterone and estrogen, can have major effects on sex hormone–dependent systems.
Changes naturally occur during male ageing which reduce the amount of testosterone effectively available to the male body. These changes alter the ratio between testosterone and estrogen (actually estradiol) in a man's body, and produce the symptoms known as partial androgen deficiency. (See Malcolm Carruther's website for more information.)
One of the most crucial factors in the metabolism of male hormones is an enzyme called aromatase, especially prevalent in fat tissue. This enzyme turns testosterone into estradiol, so changing the balance between estradiol and testosterone; men who have too much body fat, especially around the abdomen, may well have higher estrogen levels as a result of this aromatase activity. This can produce a high ratio of estrogen to testosterone. Increased estradiol is linked to decreased insulin sensitivity, and possibly blood glucose problems.
Low testosterone and excessive obesity is the so-called hypogonadal /obesity relationship, where a low testosterone level produces excess abdominal fat, which causes increased aromatase activity, which causes even more conversion of testosterone to estradiol, and this in turn naturally further reduces testosterone and then reinforces the tendency toward laying down of abdominal fat.
Sex hormones are closely affected by the level of sex hormone–binding globulin (SHBG). Only a little testosterone is free in the blood stream circulation: most of it is bound to SHBG, a specialized carrier protein which actually inactivates the sex hormones. Clearly the more the SHBG the lower the effective levels of testosterone.
Aging men with testosterone deficiency experience more aromatase activity and higher SHBG production. Overall this means the ratio of estradiol to testosterone goes up, and the bio-available testosterone level goes down. And since the liver is responsible for removing the surplus estrogen and SHBG, any deficiency in liver function - such as that resulting from alcohol consumption - can make the overall situation even worse.
Effects of Decline in Testosterone Levels With Age
Nervous system effects. Low testosterone is associated with depression and other psychological problems. Also, conventional antidepressants are of limited use because they suppress libido. Feelings of emotional health and well-being are associated with testosterone treatment. Just as importantly, cognition and alertness are affected by testosterone. Low testosterone levels correlate with scores on psychometric tests and similar effects have been observed in those men who are persuaded to take androgen-reduction agents for prostate cancer. Testosterone can protect nerve cells against several toxins, including oxidative stress. There is an association between of neurodegenerative disease and low testosterone levels.
Sexual enjoyment and function. Low levels of free testosterone reduce sexual desire, capacity for penile erection, sexual pleasure and sexual performance. Men who have low free testosterone levels find that sexual function improves when they have testosterone replacement therapy.
Cardiovascular disease and metabolic syndrome. Low levels of testosterone are associated with cardiovascular disease. The levels of testosterone are correlated with metabolic syndrome, the combination of abdominal obesity, together with high blood pressure, featuring insulin resistance, and accompanying lipid disorders in the same person. This also carries a high risk of cardiovascular disease. Testosterone replacement therapy (500 milligrams per intramuscular injection) in mid-life overweight or obese men increased insulin sensitivity. Other studies show that testosterone therapy is helpful in alleviating metabolic syndrome.
The musculoskeletal system. Bone density is the result of a balance between bone resorption and bone formation. These are controlled by several factors including estradiol and testosterone levels. Various clinical trials have demonstrated that testosterone has the capacity to increase bone mineral density in men of middle age and older. Testosterone supplementation also has improves muscle metabolism and strength.