Ageing is associated with Sarcopenia, or loss of muscle mass and strength. An average loss of 12 kg LBM (lean body mass) between the ages of 25 and 70 years and an increase in fat mass of 18-36% over a similar time (Bhasin et al., 1998).[1]

The loss of strength is seen much earlier than loss of muscle mass and may be accompanied by increasing fat mass.

Physiologic age-dependent changes (drop in growth hormone (GH), IGF-1, (menopause /andropause) explain the impaired protein synthesis, the decline of muscle mass, strength, and bone density. Harmful consequences of Sarcopenia in old age are loss of muscle strength, inducing itself loss of mobility, neuromuscular impairment, and homeostatic balance failure syndrome with gait and balance disorders. [2]

One factor is the declining levels of Testosterone. Increasing age is correlated with a rise in SHBG (sex hormone binding globulin) and therefore reduced free Testosterone. However, in obese men there is a decline in SHBG and total Testosterone.

Another important factor is insulin resistance or the diminished response to ‘insulin mediated glucose uptake’. The natural progression is to endothelial dysfunction, metabolic syndrome, diabetes and coronary artery disease.

The muscle protein synthesis in response to Insulin is reduced in elderly people, compared to younger adults. While skeletal muscle is gradually lost, vascular smooth muscle proliferates and leads to atherosclerosis (thickening and hardening of arteries).

Defects in energy production by mitochondria (the powerhouse of the cells) are contributing factors. Aging is known to reduce the DNA (genetic material) in mitochondria. This in turn results in high amounts of free radicals which attack proteins and lipids, thus interfering with vital functions.

Lack of physical activity itself is known to reduce the levels of Nitric Oxide in the Endothelium (inner lining of blood vessels). This in turn triggers a cascade of substances known to constrict blood vessels and therefore reduce the supply of oxygen and nutrition to muscles. Physical activity is among the best ways to increase Nitric Oxide and restore Endothelial Function.

Aerobic exercise was routinely recommended for cardiovascular fitness. Recently, both the American Diabetes Association and the American Heart Association have recommended ‘resistance exercises’ for obese and non obese diabetic and hypertensive elders.

Muscle mass has been shown to correlate with strength in healthy older men (Reed et al., 1991), and in turn strength has been shown to positively correlate with bio-available testosterone (van den Beld et al., 2000). This has led to interest in the hypothesis that testosterone supplementation may attenuate or even reverse age-associated Sarcopenia and enhance the physical strength and well-being of older males.[1]

Various studies have shown that testosterone replacement increases fat free mass and muscle size and strength. As well as decreases in total fat mass, beneficial effects on the distribution of body fat have been reported. Visceral fat (on CT scan) was decreased by 0•4 kg and 0•6 kg (mean) in two studies of overweight men (mean BMI 29 kg/m2) treated for 8 months with oral testosterone (Marin et al., 1992) and 9 months with transdermal testosterone (Marin et al., 1993), respectively.[1]

Older men receiving testosterone increased total and leg LBM (lean body mass), muscle volume, and leg and arm muscle strength after 6 mo. LBM accretion resulted from an increase in muscle protein net balance, due to a decrease in muscle protein breakdown. Testosterone treatment increased expression of Androgen Receptor protein at 1 mo, but expression returned to pre-Testosterone treatment levels by 6 mo. IGF-I protein expression increased at 1 mo and remained increased throughout Testosterone administration. Physiological and near-physiological increases of testosterone in older men will increase muscle protein anabolism and muscle strength. [3]

A study in rats, has shown that feeding diets with high Omega 3 fatty acids, resulted in an increased basal and LH-stimulated testosterone synthesis.[4]

Omega 3 fatty acids are also known to alter the composition of the cell membranes and improve ‘insulin sensitivity’. They are known to prevent the defect of ‘insulin receptor signaling’ in muscles [5]. Omega 3 fatty acids increase the transport of glucose and amino acids across the cell membrane.[6]

Exercise improves Nitric Oxide in the endothelium and reverses endothelial dysfunction. This improvement has a positive effect on a variety of aging factors and reduces the risk of heart disease and stroke. Insulin resistance, metabolic syndrome, muscular atrophy and erectile dysfunction are among the major factors that are positively impacted by exercise.

Improvements in nutrition can improve muscle protein synthesis and reduce muscle degradation.

Include regular exercise in your schedule to Fight Aging and Stay Young.

References:

1) Carolyn AA et al, Clin Endocrinol 60(6):653-670, 2004 )
2) Muhlberg W et al, Z Gerontol Geriatr. 2004; 37(1):2-8
3) Ferrando AA et al, Am J Physiol Endocrinol Metab. 2002; 282(3):E601-7
4) Sebokova E , J Nutr. 1990; 120(6):610-8
5) Taouis M et al, Am J Physiol Endocrinol Metab. 2002; 282(3):E664-71
6) Sohal PS, Biochem J. 1992; 286 ( Pt 2):405-11

Fight Aging Site team has taken maximum care to ensure that the information is authentic. The information has been extracted from published medical trials and text books. The information is not meant to substitute a Physicians advice, nor is it meant to treat any disease. Members are advised to consult a Physician, Dietician, Physiotherapist or Trainer before taking medication or commencing an exercise program.

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