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Thirtysomething fitness: exercise and nutritional awareness are keys to a lifetime of strength for the over 30 crowd.

Brittany Morgan has a problem. She is 34 years old, a mother of two, a buyer for a major department store and runs two miles a day. But she is gaining weight, eight pounds in the last six months. Her diet is exactly the same, down to the Snickers bar she dovours at 2 a.m. when her husband is asleep.

Morgan's problem is endemic to everyone--age. A 1988 University of Pennsylvania study on aging demonstrated that the human body slow its metabolic rate by as much at 5% by age 35. So even if a person's caloric intake remains exactly the same, that 5% reduction can add as much as 12 pounds to a 140-pound woman in a one year.

Weight gain isn't the only danger of aging. Bone loss, increased body fat, and joints degeneration are buzz words of fear for the over 30 crowd. The weapons to combat aging are many and varied, such as low-fat diets, running shoes, benches, weights and cables, calcium supplements, estrogen replacement therapy and curl bars.

"I was always calorie-conscious," says Morgan. "I began running with my boyfriend; he introduced me to the sport. Now I run every day."

The human body reaches its peak at age 25. Theat doesn't mean that at age 26 you will be falling apart, buth there is a gradual erosion of certain physical skills.

Muscular strength declines slowly throughout your 30s. Grip pressure decreases by 5% by age 36. Less protein is broken down by the body and synthesized. Consequently, there is a loss of muscle cells and muscles mass.

Vital capacity, defined as the largest amount of air you can expel from your lungs after you have taken your deepest breath, diminishes by age 35. In effect, it decreased your ability to perform strenuous exercise.

"I found that a strenuous run has more of an effect on me now," admits Morgan. "Sometimes I'll take a nap after a tough run."

Fibroblasts are actively dividing cells that build cartilage and connective tissue. By are 35, fibroblasts production decreases by 10%. This reduction can limit range of motion, decrease flexibility and increase soft-tissue injuries such as knee injuries, sore shoulders, bursitis, hyperextension of the elbow and tendonitis. Warming up becomes vital in your 30s. A study by the CNJ sports medicine clinic revealed that soft-tissue injuries were 40% more common among major league ball players over 30 than under 30. That may seem like a self-evident fact. However, the study further concludes that baseball players who follow a year-round training regimen have a lower soft-tissue injury rate regardless of age.

The most crucial part of the human body in your 30s is your bones. Contrary to popular belief, bone is dynamic, living tissue that is being constructed, hardened and broken down--normally this occurs over a four-month period.

Most people reach peak bone mass at around 30 years old. During this period, all of the bones in the body reach their maximum density. What is important to remember is that the level of that peak bone mass for each individual is markedly different and is defined by diet and lifestyle. The bones are the one part of our bodies that must be nurtured through childhood, adolescence and adulthood. By contrast, the proverbial 90-pound weakling may develop a muscular physique by beginning a proven weight training program at almost any age. Our bones, however, cannot be ignored.

Peak bone mass arrives in two stages. Around age 27, the spongy, trabecular bones such as the ribs, vertebrae and sternum reach their peak density, after which a gradual decline in density begins. Around age 35, the hard cortical bones including the femur reach their peak density.

Late in their 30s, bone loss for both men and women is about 0.5% of a person's total bone mass. Menopause usually accelerates the bone loss to a rate of 2 to 3% each year. Without treatment, significant damage will take place after only a few years.

The 1988 University of Pennsylvania study on aging concluded that bone degeneration is the single greatest health threat to men and especially to women over 40. The study outlined a guideline for risk factors and discussed possible treatments.

"Ten years ago, I ran nearly seven miles every day," Morgan says. "Soon I stopped menstruating and I became concerned. When I visited my doctor he advised that I reduced my weekly mileage and I allow my percentage of body fat to increase to a more acceptable level of 19%. He also advised a diet high in calcium."

Indeed, marathon runners, ballet dancers or any athlete who must achieve a low percentage of bodyfat is at significant risk of bone loss. The use of anabolic steroids can also significantly increase the risk of bone loss.

Weight gain your 30s can have disastrous effects in relation to bone loss because crash dieting, the usual response to weight gain, can inhibit bone development and decrease peak bone mass. Periodic weight reduction can rob a person of lean muscle tissue and increase body fat, thus creating a perfect environment for eventual weight gain.

Two factors make weight loss a difficult task in your 30s. One is the gradual decrease of your metabolic rate. Even highly trained athletes can discover an added pound or two in their 30s. Second, most people combat weight gain with a sharp reduction in caloric intake. This only serves to slow down metabolic rate even more, thereby making significant weight loss a Herculean task.

Exercise is the key. Not only does it drive up your metabolic rate 10 to 15%, but it can allow you to lose fate and gain muscle. Most diets cause a reduction in lean tissue and an increase in total body fat. This creates an imbalance in body composition and if weight gain occurs, it will be mostly body fat. Any aerobic activity done on a routine basis for at least 30 minutes will increase your metabolic rate.

A low-fat diet is essential because the thermic effect of fat is low. Fat is not burned up easily by your metabolism. Fat is metabolically prone to storage. The average American consumes a 40% fat diet. If, without consuming one fewer calorie, we reduced our fat intake to 20%, we could lose 10 pounds a year.

Crash dieting can also seriously affect bone development and peak bone mass because low-calorie diets often lack sufficient calcium. Calcium leeching begins when your diet is so low in calcium that your body begins to release the calcium from your bones and teeth. Usually, your bones can store enough calcium to remedy this defficiency, but when your diet does not contain enough calcium to replace the bone losses, the lost calcium is not restored.

The 1988 University of Pennsylvania study on aging concluded that diets too high in protein can also prevent calcium absorption and double bone loss, increasing the risk of osteoporosis by 405. In people over 40, calcium absorption becomes a problem. In the University of Pennsylvania study, postmenopausal athletes had significantly lower levels of calcium (32%) because the women did not have the estrogen necessary to encourage the production of vitamin D. The less estrogen a woman has, the harder it is for her body to absorb calcium.

Dietary factors as well as age can affect bone development. For instance, some high-fiber diets can bind calcium, making it inaccesible for use in bone building.

Besides high-protein and high-fiber diets, a diet high in salt intake interferes with calcium absorption by filtering the calcium out of the body and into the urine.

Lactose intolerance is another dietary factor that affects nearly 25% of people up to the age of 40. Because dairy products are the primary source of calcium, suitable sustitutes must be found if a person cannot tolerate digesting dairy products. Spinach, salmon and calcium-fortified foods can offset the lack of calcium from dairy products.

A second factor that can affect bone development is the consumption of calcium. The average 30-year-old man ingests only 550 milligrams of calcium a day. Since not all calcium is absorbed by the body, the average 30-year-old man is in danger of losing bone mass. In recent years, the National Institute of Health has recommended 1,000 to 1,500 milligrams a day of calcium. Dairy products, especially skim milk and yogurt, are excellent sources of calcium. However, if lactose intolerance is a problem, then a calcium supplement may be the answer.

"About two years ago, I began taking a calcium carbonate supplement," says Morgan. "I knew that as a woman and a runner I was at risk for osteoporosis."

Calcium supplements come in four forms. Calcium carbonate (the most widely used), calcium phosphate, calcium gluconate and calcium citrate. Charles Pak, M.D., an authority on osteoporosis, has found that calcium supplements can affect the density of the cortical bones such as the thigh or shaft of the forearm. However, calcium supplements have little effect on the soft bones such as the spine.

In June of 1990, Norwich Eaton Labs conducted a series of tests on a new drug named Etidronate. The study, supervised by Nelson Watts, M.D., of Emory University, demonstrated a 5% increase in spinal bone density over two years. Etidronate is a promising alternative to estrogen and calcitonin.

Postmenopausal women suffer alarming losses of bone density because as estrogen production decreases, so does the body's ability to produce Vitamin D, which is necessary for calcium absorption. For some women who cannot be treated with estrogen, calcitonin has become an accepted alternative on a limited basis.

One of the simplest ways to maintain your weight, tone your muscles and harden your bones is exercise. Exercise depletes fatty acids and increases peak bone mass. If the muscles and bones are put under regular, controlled stress, they will develop to their maximum mass.

Opponents of weight training and long distance running claim that these activities may cause osteoarthritis (the degeneration of the joints). A recent study in the Journal of the American Medical Association showed no evidence of osteoarthritis among long distance runners or body builders. In fact, it revealed increased bone mass in these athletes.

"I am careful what I eat right now," confesses Morgan. "I've given up my Snickers candy bar at 2 a.m. and replaced it with a tablet of calcium carbonate."

The 30s are potentially degenerative time for our bodies. Our body mileage begins to take its toll. The signs start slowly, almost imperceptibly--the few extra pounds that stick to our hips, sore muscles, aching joints and fragile bones. But just a few changes and some heightened awareness can halt a downward spiral and ensure a lifetime of strength.

Frank Racioppi is a freelance writer who lives in Howell, New Jersey.
COPYRIGHT 1992 Aerobics and Fitness Association of America
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Author:Racioppi, Frank
Publication:American Fitness
Date:Mar 1, 1992
Words:1795
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