August 6, 2010

Calorie restriction, exercise rejuvenate nerve connections

An article published this week in the Proceedings of the National Academy of Sciences reveals a mechanism for exercise and calorie restriction in delaying some of the effects of aging.

In their introduction, Joshua R. Sanes and his Harvard University colleagues explain that "The cellular basis of age-related behavioral decline remains obscure but alterations in synapses are likely candidates. Accordingly, the beneficial effects on neural function of caloric restriction and exercise, which are among the most effective anti-aging treatments known, might also be mediated by synapses."

Synapses are the connections that exist between nerve cells or nerves and the muscles that they control. The current research compared a synapse known as the skeletal neuromuscular junction in young adult and aged mice. In young, healthy neuromuscular synapses, nerve endings match up with their receptors on muscle fibers, enabling efficient transmission of brain signals to the muscle. However, in aged synapses, nerve shrinkage can reduce contact with muscle receptors, leading to sarcopenia, or muscle wasting.

Dr Sanes' team found a variety of age-related differences between the synapses of the young and old mice, which were significant by 18 months of age and severe at 24 months. However, animals fed a calorie-restricted diet initiated at 16 weeks of age had significant reductions in these age-associated changes. Additionally, one month of exercise performed by 22 month old mice partially reversed changes that had already occurred. The authors remark that although studies have found an association between life-style improvements and behavioral performance, to their knowledge there has been no previous evidence documented for the reversal of age-related structural alterations that could account for this.

"With calorie restriction, we saw reversal of all aspects of the synapse disassembly," noted Dr Sanes, who is a professor of molecular and cellular biology and director of the Center for Brain Science at Harvard. "With exercise, we saw a reversal of most, but not all."

"Caloric restriction and exercise have numerous, dramatic effects on our mental acuity and motor ability," he stated. "This research gives us a hint that the way these extremely powerful lifestyle factors act is by attenuating or reversing the decline in our synapses."

"These findings in neuromuscular synapses make us curious to know whether similar effects might occur in brain synapses," he added.

Getting the most from exercise

Exercise has been proven to improve the quality of life in people disabled by diabetes, muscular dystrophy, stroke, multiple sclerosis, myasthenia gravis, and chronic obstructive pulmonary disease (Stout JR et al 2001; Rochester CL 2003). Regular exercise can improve blood glucose control, delay or prevent type 2 diabetes, offset age-associated increases in inflammatory cytokines, and reduce cardiovascular risk, diabetes-related mortality, and depression (Goldney RD et al 2004; Vitartaite A et al 2004; Babyak M et al 2000; Suh MR et al 2002; Church TS et al 2004; Short KR et al 2003; American Diabetes Association 2003; McFarlin BK et al 2004).

As humans age, our muscles atrophy and weaken (a condition termed sarcopenia), regardless of exercise regimen or lifestyle (Bross R et al 1999). The muscles become smaller and less elastic, and muscle injuries become more common (Bross R et al 1999; Baumgartner RN et al 1998). The ability to recover from injuries also decreases, as does tolerance for exercise.

Our senior years are a good time to exercise. Exercise by older people improves quality of life. Sarcopenia, even in severe cases, can be reversed through strength training (Aniansson A et al 1981; Frontera WR et al 1992). Exercise has also been shown to control body weight (very important in preventing diabetes, cardiovascular disease, and hypertension) and strengthen bones. It is important for older people to engage in regular, low to moderate exercise rather than strenuous activity (Martini FH 1995).

There are many benefits to a program of regular exercise. In addition to enhanced self-esteem, exercise can promote weight loss and aid in the prevention of a number of diseases, including heart disease and diabetes. In addition, the following nutrients have been shown to enhance muscle function, promote quicker recovery after exercise, and increase strength:

• Creatine
• Carnitine—1000 to 2000 milligrams (mg) daily
• Carnosine—1500 to 3000 mg daily
• Branched-chain amino acids—containing at least 1200 mg L-leucine, 600 mg L-isoleucine, and 600 mg L-valine
• Glutamine—500 to 1000 mg daily
• Whey protein—consider taking 20 to 80 grams (g) whey protein daily. It is most important to consume whey protein before and immediately after your exercise session to make sure adequate protein is available to depleted muscles.
• Polyenylphosphatidylcholine (PPC)—900 to 1800 mg

In addition, bioidentical hormone therapy may be considered to balance levels of important sex hormones, including testosterone.

Life Extension Update

• Animals on calorie restricted diets stay fit longer
• Brain cocktail proposed by MIT team
• Vitamin E and melatonin help prevent cognitive deficits in diabetic rats

What's Hot

• Dieting beats out exercise in mouse study
• Little things mean a lot

Life Extension Magazine®

• Activate your longevity genes: five natural compounds simulate caloric restriction
• The calorie restriction society research project

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