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describe the hypotheses about the causes of aging
- Errors occur in copying the genetic blueprint (DNA) – once sufficient errors in DNA copying accumulate, a cell can no longer synthesize the major proteins needed to function and it dies. Damage to DNA in the mitochondria also contributes to the aging process.
- Free radicals damage cell parts – electron-seeking free radicals can bread down cell membranes and proteins. DNA in mitochondria typically shows this type of damage, and this damage is linked to the aging process. One way to prevent this free radical damage throughout the body is to consume adequate amounts of antioxidants.
- Neuroendocrine communication & coordination diminish. – Neurological & endocrine systems work together to regulate hormone secretions. With age, the communication & coordination between these systems decline. The blood concentration of many hormones, such as testosterone in men, falls during he aging process. Replacement of this and other hormones is possible, but the resulting risks & benefits are largely unknown.
- The immune system loses some efficiency. – the immune system is most efficient during childhood and young adulthood, but with advancing age, it is less able to recognize & counteract foreign substances, such as viruses that enter the body. Nutrient deficiencies can impair immune function.
- Autoimmunity develops – autoimmune reactions occur when white blood cells & other immune system components begin to attack body tissues. Many diseases, including some forms of arthritis, involve this autoimmune response.
- Cross-linking or glycosylation of proteins occurs. – body proteins develop attachments or unnecessary cross-links hat damage proteins or affect their function. For example, blood glucose, when chronically elevated, attaches to (glycate) various blood and body proteins. This action decreases protein function and can encourage the immune system to attack these altered proteins. Cross-linking also may decrease flexibility in key body components, such as connective tissue.
- Death is programmed into the cell. – each human cell can divide about 50 times. Once this total number of divisions occur, the cell dies.
- Excess energy intake speeds body breakdown. – underfed animals, such as spiders, mice and rats, live longer than those that are well fed. Usual energy intake must be reduced by about 30% to see this effect. Currently, this approach is the only proven way to substantially slow the aging process.
describe how physical and physiological changes that occur during adulthood affect nutritional needs
The physical & physiological changes in body composition & body systems that occur during adulthood can influence dietary intake, alter nutrient and/or calorie needs and/or alter nutrient utilization. The use of medications & supplements can improve health and quality of life, but some also can adversely affect nutritional status.
Body composition – gradual decline in lean body mass (sarcopenia) and body water; slow increase in fatty tissue & redistribution of body fat from the limbs to the torso. Nutrition Implications – loss of lean body mass decreased metabolic rate, causing calorie need to drop. Fluid intake is important because a decrease in total body water elevates the risk of dehydration & decreased the body’s ability to regulate temperature. Increases in fatty tissue raise the risk of developing conditions (high blood pressure, high blood glucose levels, type 2 diabetes, heart disease and certain cancers) that may alter nutrient needs.
Skeletal System – slow, steady loss of bone minerals; in women, loss rises greatly in the first 5-10 years after menopause; may lead to osteoporosis. Nutritional Implications – adequate calcium & vitamin D during young adulthood helps build bone density & in the remainder of adulthood maintain & even increase bone mass. If osteoporosis caused adults to limit physical exercise, calorie needs will drop.
Cardiovascular & Respiratory Systems – gradual decrease in the ability of the heart & lungs to deliver oxygen and nutrient rich blood to body cells (aerobic capacity) & remove metabolic wastes; rise in blood pressure. Nutritional Implications – reductions in cardiovascular & respiratory systems affects the function of other organs (kidney, brain) & decrease their function, thus lowering calorie needs and possibly altering nutrient needs. If cardiovascular & respiratory system declines cause adults to limit physical exercise, calorie needs will drop further.
Digestive System – diminished chewing ability if gum disease occurs & leads to tooth loss or poorly fitting dentures; decline in efficiency of digestion & nutrient absorption due to reduced secretions of HCl and gastric, pancreatic and intestinal digestive enzymes; Decline in vitamin B-12 absorption due to decreased secretion of intrinsic factor; decline in the liver’s ability to metabolize alcohol & drugs. Slowdown in the movement of chime through the intestines. Nutritional Implications – chewing problems may result in reduced intake of crisp or chewy foods, such as ray fruits & veggies, whole grains and meats. Low HCl levels may impair absorption of iron, calcium, folate, vitamin b-6, and protein. Low HCl levels also may allow larger than normal numbers of bacteria to survive & establish colonies in the small intestine, where they may impair fat and fat soluble vitamin absorption, complete for b-vitamins, and lead to weight loss and vitamin deficiencies. Diminished secretions of HCl and intrinsic factor halt vitamin B-12 absorption. Reduced secretions of digestive enzymes impair digestion & absorption of macronutrients. Decline in liver function slows detoxification of alcohol & drugs
Urinary System – decreased efficiently of kidneys in filtering out metabolic wastes, concentrating urine, & putting vitamin D synthesized in the skin in its active form; progressive weakening of the muscles that control urination. Nutritional Implications – diminished kidney function may impair re-absorption of glucose, amino acids, and vitamin C & impair vitamin D status. Excessive intakes of protein, electrolytes, water-soluble vitamins, & other substances that must be filtered bout by the kidneys should be avoided. Vitamin D rich foods need to be emphasized or supplements may be needed. Reductions in the ability to concentrate urine increase the need for fluid.
Nervous System – gradual decline in number of cells that transmit nerve signals, which may result in decreased sensory perceptions (taste & smell), slowed reaction times & impaired neuromuscular coordination, reasoning & memory. Nutritional Implications – loss in taste & smell may reduce desire to eat, leading to weight loss. Diminished sensory perceptions may decrease secretions from the salivary glands, stomach, & pancreas and result in impaired digestion & blood glucose regulation. Neuromuscular coordination losses make it difficult to cook/feed oneself. Reduced reasoning abilities can result in an inability to choose a nutritious diet, & memory losses may result in forgetting to eat.
Immune System – progressive decline in efficiency increases susceptibility to infections & disease. Nutritional Implications – calorie & nutrient needs rise during infection & disease.
Endocrine System – Gradual decrease in hormone synthesis, hormone release or sensitivity to hormones. Nutritional Implications – decrease in sensitivity to insulin takes longer for blood glucose levels to return to normal after a meal. Reduction in thyroid hormone slows metabolic rate & increases calorie need. Decline in growth hormone leads to loss of lean body tissue & an increase in adipose tissue, both of which decrease metabolic rate and calorie need. Growth hormone reductions also cause the thinning of skin.
Reproductive System- females; few changes until menopause (characterized by diminishing estrogen secretions and cessation of ovulation); Males: show decline in testosterone after age 60. Nutritional Implications – in females, iron needs drop when menopause occurs. Healthy diets & exercise are important after menopause because the decline in estrogen causes the risk of heart disease and osteoporosis to soar. In males, the reduction in testosterone may contribute to the loss of lean body tissue, which diminishes calorie needs.
list the potential benefits & risks associated with the use of complementary & alternative medicine practices
Alternative therapies have little or no scientific evidence to support them. Some herbal products may be harmless, others are potentially toxic, & others may be effective for some problems but dangerous when taken in the wrong dose or by people with certain medical conditions. Herbal products should be used with great caution.
discuss the energy sources for muscles during exercise
- At rest, muscle cells use mainly fat for fuel.
- For intense exercise of short duration, muscles use mostly phosphocreatine (PCr) for energy.
- During more sustained intense activity, muscle glycogen breaks down to lactic acid, providing a small about of ATP.
- For endurance exercise, both fat and carbohydrate are used as fuels; carbohydrate is used increasingly as activity intensifies.
- Little protein is used to fuel muscles.
- Fuel sources for muscle cells can be estimated based on percent of VO2max.
describe the fluid & nutritional needs of athletes.
- To maintain the body’s ability to regulate internal temperature, athletes must consume sufficient fluids because dehydration leads to a decline in endurance, strength, and overall performance and sets the stage for heat exhaustion, heat cramps, and potentially fatal heatstroke. During exercise, the recommended fluid status goal is a loss of no more than 2% of body weight. Most experts recommend drinking spots drinks with electrolytes instead of water.
- The composition of food eaten before, durng and after athletic events or exercise training sessions can affect performance and the speed with which the athlete recovers from the exercise bout. Pre-exercise training meals keep the athlete from feeling hungry before and during the exercise bout and maintain optimal levels of blood glucose for the exercising muscles. The pre-exercise meal should be high in carbohydrate, low in fat, and readily digested. For sporting events lasting more than 60 minutes, consuming carbohydrate during actifity can improve athletic performance. Carbohydrate rich foods and a small amount of protein should be consumed 30 min. after exercise and again at 2 hour intervals for up to 6 hours.
explain the role of ergogenic aids & describe their effect on athletic performance
An ergogenic aid is a nutritional, psychological, pharmacological, mechanical or physiological substance or treatment intended to improve exercise performance. Most of these aids are ineffective.
dependent physical and physiological changes in body structure and function that occurs normally and progressively throughout adulthood as humans mature and become older.
cessation of menses in women, usually beginning at about age 50.
Complementary alternative medicine (CAM)
Medical or health-care system, practice, or product not presently part of conventional medicine; also called complementary care and integrative medicine.
not requiring oxygen
organic molecule in muscle cells that serves as a part of the high-energy compound creatinephosphate (phosphocreatine).
a mechanical, nutritional, psychological, pharmacological, or physiological substance or treatment that is intended to directly improve exercise performance.
Which nutrients tend to be too low in the diets of adults?
Common dietary inadequacies include vitamin D and E, folate, magnesium, calcium, zinc, and fiber.
What are some examples of how a healthy diet can benefit adults?
A healthy diet can help people preserve the body’s function, avoid chronic disease and age successfully.
Discuss three physiological changes experienced by older adults, and describe ways to meet their nutrient needs despite these changes.
- Immune System – progressive decline in efficiency that increases susceptibility to infections and disease. Calorie and nutrient needs rise during infection and disease. Eating a diet that meets nutrient needs and preventing obesity can help lower the risk of immune dysfunction.
- Endocrine System – Gradual decrease in hormone synthesis, hormone release or sensitivity to hormones Eating nutritious diet may influence endocrine activity by providing ample quantities of compounds necessary for hormone synthesis and transport.
- Nervous System – gradual decline in number of cells that transmit nerve signals, which may result in decreased sensory perceptions (taste & smell), slowed reaction times and impaired neuromuscular coordination, reasoning and memory. Experimenting with herbs, spices and flavorings can boost the taste and smell of foods. Drinking enough fluids to prevent dehydration, engaging in lifelong learning, and getting enough sleep can help avoid mental confusion.
What is the main form of energy that cells use?
Adenosine triphosphate (ATP)
What fuels anaerobic exercise?
What fuels aerobic exercise?
Carbohydrate & fat.
Why is creatine so important for fueling high-intensity, short-duration exercise?
Paired with ATP, creatine can be formed into Phosphocreatine(PCr), a high energy compound that is stored in small amounts in the muscle cells. PCr can function as the major source of energy for events lasting up to about 1 minute. PCr can be activated instantly and can replenish ATP quickly enough to meet the energy demands of the fastest and most powerful sports events such as throwing and sprinting.
How does fitness level affect the fuels burned for exercise?
The rate at which muscles use fatty acids is affected by training level. The more trained a muscle, the greater its ability to use fat as a fuel. Training allows an athlete to use fat for fuel more readily, thereby conserving glycogen for when it is really needed – such as for a bust of speed at the end of a race.
When is protein used as a fuel source during exercise?
Endurance exercise is when protein is most likely to make its most significant contribution as a fuel source, even then, it provides limited energy, with estimates ranging from 3-15%.
What role does protein have in resistance exercise?
Protein is used least in resistance exercise. Endurance exercise is when protein is most likely to make its most significant contribution as a fuel source, even then, it provides limited energy, with estimates ranging from 3-15%.
What is causing him to be so fatigued that he cannot finish his workout?
He is not eating enough carbohydrate and fat. Carbohydrates and fats are needed for energy to lift weights. Protein is not a good energy source in resistance exercise.
Should a person consume more protein, to build muscle?
No, needs to be eating more carbohydrate, moderate protein foods immediately after a weight-training workout can enhance the anabolic effect of the activity. This most likely increased blood concentration of insulin and growth hormone and contributes to protein synthesis. It is impossible to increase muscle mass simply by eating protein; putting physical strain on muscle through strength training or other physical activity is needed, as is adequate protein intake to support growth & recovery.
What is the easiest way for athletes to assess calorie intake?
By accessing their weight, if they are losing weight, they are not eating enough, if they are gaining weight, they are eating too much.
What is glycogen loading?
Exercise and eating regimen that increases the amount of glycogen stored in muscle to levels higher than normal.
How does iron-deficiency anemia affect athletic performance?
Because iron is involved in red blood cell production, oxygen transport, and energy production , a deficiency of this mineral can noticeably detract from optimal athletic performance.
How much fluid should an athlete drink after exercise?
Drink 3 cups of fluid for each pound lost during exercise.
List five specific nutrients that athletes need and the appropriate food sources from which these nutrients can be obtained.
- Carbohydrates – cereal, whole wheat toast, granola bar
- Fat – egg, milk, yogurt, almond butter, peanut butter. Protein - turkey breast, salmon, lean beef.
- Iron – protein, fortified cereals
- Calcium – milk, low-fat yogurt.
The diets of adults tend to be low in _____.
a. vitamin E
e. all of the above
e. all of the above
a change that tends to occur as the adult years progress is _____.
- decreased lung efficiency
- decreased hormone synthesis and release
Which mode of exercise is defined as any activity that uses large muscle groups, can be maintained continuously, and is rhythmic in nature?
The predominant fuels for the 0 meter sprint are _______.
ATP & Phosphocreatine
The predominant fuel for a 2 hour marathon is _________.
The amount of ATP stored in a muscle cell can keep a muscle active for about _____.
There are 4 main types of muscle fibers.
What type of athletes would not benefit from carbohydrate loading?
Athletes who are involved in endurance activities may need to consume _____ grams of carbohydrates per kilogram of body weight.
up to 10
What 3 factors are included in the female athlete triad?
- menstrual disturbances/amenorrhea
- energy deficit/disordered eating
- bone loss/osteoporosis