Aging and decline in Testosterone levels
Aging and decline in Testosterone levels

Testosterone is the male sex hormone. It is produced in the testes and is essential for sexual activity and reproduction. It is the hormone responsible for the secondary sexual characteristics like facial hair, body hair, male pattern baldness and virile features. The greater musculature in men is attributed to Testosterone and Bodybuilders are great fans of Testosterone. The ovaries also produce a small quantity of Testosterone.

The body produces Testosterone in a carefully regulated manner. The pituitary gland and the hypothalamus send messages to the testes to produce testosterone. The hypothalamus controls Testosterone production through a hormone called Gonadotropin releasing hormone (GnRH). This hormone stimulates the pituitary gland to release Follicle stimulating hormone (FSH) and Luteinizing Hormone (LH) which in turn stimulates the testes to produce Testosterone. When the levels of Testosterone are high, the brain sends a signal to the pituitary gland to make less LH. If the Testosterone levels are low, the brain sends signals to make more LH, leading to an increase in Testosterone production by the testes. If external Testosterone is provided, the natural production is suppressed by this mechanism. Prolonged external supplementation of Testosterone can lead to atrophy of the testes and a total shut down of natural production.

The levels of total testosterone are generally between 300 to 1200 nanograms per deciliter (ng /dl). Testosterone is mostly bound to other proteins and only 2% circulates as free testosterone. In Bodybuilding circles, it is believed that free testosterone is the major contributor to muscle anabolism. About 40% of total testosterone is bound to ‘Sex Hormone Binding Globulin (SHBG) and 58% is bound to albumin. Elderly men have a greater quantity of SHBG.

Serum testosterone has a circadian rhythm in normal young men, with peak levels in the morning, coinciding with sunrise, and low levels in the evening, coinciding with sunset. This appears to be nature’s way of preparing us for the activities during the day. Foraging for food, hunting or escaping from predators was possible due to this special feature. The modern lifestyles are probably out of tune with nature’s design. The ancient pattern of multiple bouts of intense activity and frequent eating is just not followed today. This alone may cause many imbalances. Recently studies have shown that intense short bursts of exercise stimulate testosterone release. Conversely, sedentary lifestyles may contribute to low testosterone levels. In elderly men, the early morning peak of Testosterone is blunted compared to younger males.


There is a steady decline in the levels of Testosterone, with increasing age. The decline begins in the late thirties and continues to decline at 0.8 % per year according to some studies and 1.6% per year (Massachusetts Male Ageing Study, MMAS; Feldman et al., 2002). Aging is associated with lower levels of LH and therefore Testosterone. Simultaneously, there is an increase in SHBG, leading to lower levels of free Testosterone available to tissues like muscles.
When aging is faster than, the chronological aging, in one or more organs of the body, the risk of disease and death rises alarmingly. The damaged ‘weak link’ may affect the survival of the whole organism.

Low testosterone levels were linked with an increase in mortality in a cohort of male veterans, according to the results of a study reported in Archives of Internal Medicine [1]. Low testosterone was defined as a total testosterone level of less than 250 ng/dL or a free testosterone level of less than 0.75 ng/dL.

Physical symptoms of low Testosterone in males, include low sex drive, erectile dysfunction, lower sperm count, low energy, depression and flabby breasts (Gynecomastia). This is sometimes called ‘Andropause’, but it is not a well-defined term.

At a later stage, brittle bones, loss of memory and senility may set in. There are many other causes of low testosterone which may require urgent medical attention. For many years Testosterone Replacement Therapy (TRT) was being used for improving the quality of life of elderly men. However, there were doubts about the Cardiovascular safety and also about the possibility about prostatic hypertrophy or even prostate cancer. In recent years many meta analyses have laid all those fears to rest. In a long-term observational study, it was found that TRT with Testosterone Undecanoate (TU) reduced CV mortality by 66% to 92%. It was concluded that long-term TU was well tolerated with excellent adherence suggesting a high level of patient satisfaction. [2]

Normal Testosterone Levels by Age in Healthy Men
Adapted from Vermeulen et al, Androgens and the Aging Male (pp. 3-14). New York: Parthenon Publishing

Age

Total Testosterone ng/dl

Free testosterone ng/dl

SHBG nmol/L

25-34

617

12.3

35.5

35-44

668

10.3

40.1

45-54

606

9.1

44.6

55-64

562

8.3

45.5

65-74

524

6.9

48.7

75-84

471

6.0

51.0

85-100

376

5.4

65.9


Note: There is significant variation (plus or minus 25-30%) in levels between individuals.
ng/dl = nanograms per deciliter and nmol/L = nanomoles/Liter

 

A healthy lifestyle which includes participation in sports and moderate to rigorous exercise may be one of the best ways to prolong youth. Natural and artificial methods of boosting Testosterone will be the subject of another article on Body Satva.

Prolong Youth by leading an ‘enlightened and balanced life

References:
1. Shores MM et al, Arch Intern Med. 2006 Aug 14-28;166(15):1660-5
2. Traish AM et al, Journal of Cardiovascular Pharmacology and Therapeutics 2017, Vol. 22(5) 414-433

Disclaimer
Body Satva Essentials’ Team has taken maximum care to ensure authenticity of the information provided, by sourcing from reputed medical journals and books. Body Satva Essentials’ Team urges members to seek professional advice before commencing any regimen of diet, exercise and medication. The products sold on this site are not for treating any disease or medical condition, without medical supervision. We do not advice self-medication.

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