Aruna Venkatesh MDStaff EndocrinologistTexas Diabetes InstituteSan Antonio, Texas, USA
How much do you need? How does it help? Keeping active can help people maintain a healthy weight or lose weight. It can also lower the risk of heart disease, diabetes, stroke, high blood pressure, osteoporosis, and certain cancers, as well as reduce stress and improve mood.
Globally, one in three people gets little or no physical activity. Jobs requiring physical activity have decreased while sedentary jobs have increased 10-40%. The number of school children walking or riding to school, decreased from 40% in 1969 to13% in 2001. This in turn is contributing to the global epidemic of obesity and the attendant chronic disease.
Obesity and Diabetes are tracking each other so closely that they have earned a new name - "DIABESITY". Overweight and obesity occur when there is energy imbalance: fewer calories are expended than are consumed through food and beverages. Reduction in caloric intake is of primary importance in achieving / maintaining weight loss.
People vary a great deal in how much physical activity they need to maintain a healthy body weight, to lose weight, or to keep weight off. Though used interchangeably, "physical activity” refers to anybody movement that burns calories. “Exercise,” a subcategory of physical activity, refers to “planned, structured, and repetitive” activities aimed at improving physical fitness and health.
The intensity of physical activity is measured in metabolic equivalents or METs. One MET is defined as the calories burned while an individual sits quietly for one minute. For the average adult, this is about one calorie per every 2.2 pounds of body weight per hour; someone who weighs 160 pounds would burn approximately 70 calories an hour while sitting or sleeping. Moderate intensity physical activity is activity sufficient to burn 3-6 times calories burnt at rest (3-6 METS).
Vigorous activity is activity sufficient to burn over 6 times at rest ( > 6 METS). Physical activity prevents obesity by:
1) Increasing people’s total energy expenditure, as long as they don’t eat more to compensate for the extra calories they burn.
2) Decreasing fat around the waist and total body.
3) Muscle-strengthening which increases energy expended at rest.
4) Reducing depression and anxiety PREVENTION OF WEIGHT GAIN: Adults need at least 2.5 hours of moderate-to-vigorous physical activity (brisk walking at 4 mile - an-hour pace) each week, while children need 1 hour a day.
Moderate-intensity walking should be at about a 4 mile-an-hour pace. WEIGHT LOSS: To lose more than 5 percent of body weight and keep it off, caloric intake needs to be reduced and over 300 minutes of moderate-intensity activity a week is necessary
HEALTH BENEFITS OF PHYSICAL ACTIVITY:
*Regular physical activity reduces the risk of many adverse health outcomes Lower risk of coronary heart disease, stroke, high blood pressure, adverse blood lipid profile, type 2 diabetes, metabolic syndrome, colon and breast cancer, falls and depression.
*40% lower risk of early death FEW lifestyle choices have as large an effect on mortality as physical activity This benefit begins at 150 minutes of at least moderate-intensity aerobic physical activity a week and maximal at 7 hrs a week *Reduction in risk of colon and breast cancer needs 3.5 to 7 hrs a > week of moderate-intensity physical activity. These benefits are not seen at 150 min/ week.
*Mental health benefits are seen at 30-60 min at a time, 3-5 days a week and begin at lower levels. Benefits are seen as early as at 4 to 6 weeks.
Both aerobic (endurance) and muscle-strengthening (resistance) physical activity are beneficial - Benefits are seen across all ages, races and ethnic groups and for people with disabilities - Most health benefits occur with at least 150 minutes a week of moderate-intensity physical activity (brisk walking) - Additional benefits occur at higher intensity, greater frequency, and/or longer duration physical activity - Some physical activity is better than none Modern day home and work landscapes promote sedentary lifestyles, including prolonged sitting and limited ability to engage in physical activity. It is imperative to take proactive steps to ensure about 30-60 minutes of daily physical activity.