Exercise, Nutrition, and Health

The interconnection of regular exercise and proper nutrition, two key components of maintaining good health.

Regular exercise as a way of promoting health can be traced back at least 5,000 years to India, where yoga originated. In China, exercises involving martial arts, such as tai chi, qi gong, and kung fu, developed at least 1,500 years ago. The ancient Greeks had exercise programs 2,500 years ago, which led to the first Olympic games in 776 BC. It only has been within the last 100 years that the scientific and medical communities have documented the benefits that even light but regular exercise has on physical and mental well-being. Exercise comes in many forms but there are three basic types: resistance, aerobics, and stretching. These are generally classified in three areas: upper and lower body and the abdomen.

Eating a nutritious diet is not hard to do. It should contain a variety of foods, including vegetables, fruits, whole-grain products (breads, cereal, and pasta), lean meat, poultry, and fish, beans, and lowfat or nonfat dairy products. Foods to avoid include those that contain sugar, salt, saturated fat, transsaturated (trans) fat, processed food, fast food, and alcohol.

Regular exercise and proper nutrition is essential for people of all ages, from teenagers to seniors. In the United States, less than 10% of high school boys meet the minimum requirements of physical activity, according to the U.S. Centers for Disease Control and Prevention (CDC). The CDC recommends teenage males get at least an hour of aerobic exercise a day, and a minimum of three hours a week of musclestrengthening exercise. For middle-aged men, at least 45 minutes of moderate aerobic activity a day and 45 minutes three times a week of resistance or strength training. Research shows that men slowly start to lose muscle mass and strength beginning at about age 30. In middle age men, metabolism also slows, allowing fat to accumulate, especially around the abdomen. In men age 65 and older, physical fitness is important to help maintain muscle tone, stamina, flexibility, and balance. Exercise for seniors should include 30 minutes a day of light to moderate aerobics (such as walking briskly) and 30 minutes two or three times a week of resistance exercise, including 5–10 minutes each of warm-up and cool-down exercises that includes stretching.

Good nutrition can help prevent a wide range of diseases and promote overall good health. The six groups of nutrients the body needs come primarily from food and are protein, carbohydrates, fats, fibers, vitamins, and minerals. The remaining nutrients come from water. Nutrition modification is used to treat a number of disorders, including allergies, anemia, arthritis, colds, depression, fatigue, high blood pressure (hypertension), obesity, insomnia, headaches, and stress.

The benefits of proper nutrition and fitness on health are enormous, including reducing the risks of heart disease, stroke, cancer, diabetes, high blood pressure, and high cholesterol. The medical community recognizes that regular exercise, along with a proper diet, is one of the two most important factors in maintaining good physical and mental health, and in preventing and managing many diseases. Most certified physical trainers advocate at least 20 minutes of exercise at least three times a week. But for people who have a sedentary lifestyle, even walking for 10 minutes a day has health benefits.

The United States has the highest percentage of people who are overweight or obese in the world, according to the World Health Organization (WHO). More than two-thirds of adults in the United States are overweight or obese, and one-third of American adults are obese, according to the U.S. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). The problem is worse in American men—more than 72% of adult males are overweight or obese. In Canada, about one in four adults are obese, according to a 2011 report by the Public Health Agency of Canada. In Europe, obesity rates have tripled from 1980 to 2008, according to WHO. The United Nations agency reports that roughly half of all European adults are overweight or obese as of 2008. The primary reasons for obesity cited by the report are a lack of physical activity and a poor diet low in nutrition and high in calories. Besides the United States, countries with rates of overweight and obesity over 20% are Mexico, United Kingdom, Slovakia, Greece, Australia, and New Zealand.

The generally accepted way to define overweight and obese is to estimate body mass by figuring out body mass index (BMI). An individual's BMI is calculated based on height and weight. A BMI calculator is available from the NIDDK at http://www.nhlbi.nih.gov/health/health-topics/topics/obe/diagnosis.html . A normal-weight BMI is 18.5–24.9, an overweight BMI is 25–29.9, an obese BMI is 30–39.9, and a BMI of 40 or higher indicates extreme obesity, according to the NIDDK. Being overweight or obese increases the chances of getting heart disease, high blood pressure (hypertension), high cholesterol, diabetes, cancer, and stroke. The primary cause of obesity is taking in more calories than are expended in energy (physical activity). Treatment generally includes diet modification (good nutrition) and exercise. Obese and seriously obese people should consult their physician before starting exercise or a weight loss diet.

There are no diseases or conditions associated with good nutrition or exercise, except sore muscles after starting or increasing exercise. Too much of certain vitamins and nutrients can be harmful, but this usually occurs from over-supplementation, not from the diet. These include vitamins A, B₁, B₆, C, and D, and the minerals phosphorus and zinc. There are a number of disorders that can result from poor nutrition. A high-fat diet increases the risks of obesity, heart disease, diabetes, and breast cancer. A low-fiber diet can cause or contribute to high cholesterol, constipation, diabetes, obesity, cancer, and hemorrhoids.

See also Nutritional supplements ; Obesity .