AGING OF THE MUSCULAR SYSTEM AND PHYSICAL EXERCISE

What is the role of mitochondrial dysfunction in glucose intolerance and type 2 diabetes?

insulin stimulates transcription and translation of mitochondrial genes and proteins and increases Mitochondrial ATP production rate. However with glucose interolerance, caused by Type 2 Dibetes, this response is blunted leading to mitochondrial dysfunction

Physical exercise has a wide spectrum of beneficial effects in the elderly. Summarize the main aspects.

regular physical activity reduces risk of cardiovascular disease, thromboembolic stroke, hypertension, type 2 diabetes mellitus, osteoporosis, obesity, colon cancer, breast cancer, anxiety, and depression.

Summarize the age-related changes in skeletal muscle.

in older individual they commonly have less muscle mass than younger individuals. This muscle atrophy is thoguht to be brought about by a decrease in both the number and size of muscle fibres. Fast twitch fibres are thought to atrophy because the nerves that innervate them die and cannot be maintained without innervation. The process that gives rise to age dependent muscle atrophy is known as sarcopenia and arises as a result of mitochondrial damage and deteriorated muscle fibril is replaced initially by connective tissue and eventually fat.

How can the mtDNA damage be related to the free radical (oxidative damage) theory of aging and sarcopenia?

Accumulation of oxidative damage induced by free radicals causes mtDNA mutations and deletions, resulting in reduction in mitochondrial protein content. As a result of such decline in mitochondrial protein, there is loss of mitochondrial functionality, as described above, which can account for muscle dysfunction. With aging, there is a decline in the ability to repair such oxidative damage thereby causing the cascade of events leading to muscular dysfunction. thus Age related sacropenia, muscle weakness and reduction in aerobic capacity is a result of loss in functionality of mitochondrial capacity.

What is the effect of aerobic exercise on muscle mitochondria?

Aerobic exercise enhances muscle mitochondrial biogenesis, enhancing mtRNA transcription and translation. Thereby increasing oxidative enzyme content.

Summarize the main points of the recommendations of the US College of Sports Medicine for aerobic and muscle strengthening training. What are the benefits of greater amounts of activity, flexibility, and balance?

For Aerobic activity: to promote and maintain heealth, older adults need moderate-intensity aerobic physical activity for a minimum of 30 minutes 5 days each week or vigorous intensity for a minimum of 20 minutes 3 days a week. for muscle strengthening adults will benefit from performing activities that maintain or increase str and endurance for a minimum of 2 days each weeks (8-10 exercises on 2 or more nonconsecutive days / week) Benefit of greater activity = further reduce their risk for premature chronic health conditions and mortality related to physical inactivity. In addition, to further promote and maintain skeletal health, benefits of flexibility =maintain the flexibility necessary for regular physical activity and daily lif benefits of balance = reduce risk of injury from falls

According to the DNA changes (damage and mutations) theory of aging, DNA and RNA damage is responsible for changes in muscle tissue. Discuss this statement.

In the theory of DNA damage and repair, extensive damage can activate apoptosis of the muscle cell and with declining activity of repair mechanisms, such apoptosis may cause permanent alterations to muscular tissue structure / funcitonality . However, DNA damage is not the only contributing factor that results in alterations of muscle tissue. Crosslinking of collagen fibres can lead to loss of elasticity which results weakened contractility and decreased functional movement.

Explain how and what causes the decline in muscle mtDNA and why it affects muscle performance in elderly people.

Reduced muscle mitochondrial function could contribute to age-related muscle dysfunction and reduced aerobic capacity via loss of capacity for mitochondrial ATP production in skeletal muscle. This decline in mitochondrial function is associated with mitochondrial dysfunction by reducing template availability for transcription and translation of key mitochondrial proteins, as a result of mtDNA declination associated with aging and accumulated oxidative damage, thus leading to decline in mitochondria to perform oxidative phosphorylation in older muscles.

Describe the main differences between exercise recommendations for adults and older adults.

the main difference b/w for adults and older adults are: Aerobic intensity- The older adult recommendation defines aerobic intensity as relative to fitness, in the manner of an exercise prescription. For aerobic exercise, ACSM recommends a target intensity of 50-85% of oxygen uptake reserve—a range that includes both moderate and vigorous exercise (the range for adults requires relatively vigorous effort or impossible for older) Strength acitivities: High intensity training is an option for older adults, preferably in supervised settings or in adults. Older adults can meet reccomendations through calisthenics or progressive weight training flexibility: At least 10 min of flexibility activities is recommended based upon the time required for a general stretching routine involving major muscle and tendon groups with 10-30 s for a static stretch and 3-4 repetitions for each stretch (20). Preferably, flexibility activities are performed on all days that aerobic or muscle-strengthening activity is performed

Describe the important roles that mitochondrial DNA and RNA (mtDNA/mRNA) play in muscle function.

the role of mitochondrial DNA and RNA in muscle function is that it is associated with ATP production rate. Encoding the proteins necessary for oxidative phosphorylation. If there is damage to the DNA, RNA synthesis within mitochondria, decreases resulting in less protein translation and ATP synthesis being impaired, causing in muscular dysfunction