The benefits of exercise for chronic disease risks are widely known. For example, with regular exercise, you can reduce your risk of developing Type 2 diabetes, various cancers, heart disease, stroke and osteoporosis.
The role of exercise on weight loss remains inconclusive. Many experts believe that exercise has minimal effect on weight loss and that what we eat is what really matters. Drilling down to a deeper level may provide a better understanding. The number on the scale is just one measure of the effect of exercise.
Another commonly used measure is body mass index (BMI), which is a convenient way to indirectly calculate body fat based on your weight in relation to your height. BMI does not take into account lean mass versus fat mass. Lean mass includes everything in your body except fat, such as muscles, bones, organs and other non-fat tissues. BMI is not considered to be reliable because highly muscular people such as bodybuilders may fall into the overweight category.
When it comes to your health, body composition is more important than total body weight. For example, one person weighing 200 pounds can be obese with a high amount of body fat, while another person of the same weight can be muscular and have normal or low body fat. Similarly, a lightweight person can have a high percentage of body fat. Waist circumference is considered a useful measure because abdominal obesity (above 88 cm in women and 102 cm in men) is a risk factor for many diseases.
Steady-state aerobic exercise was long considered the gold standard of exercise for fat loss. Recently, high-intensity (anaerobic) interval training has moved to the forefront of fat-busting. However, resistance exercise (also known as strength training) improves functional abilities, builds muscle and increases metabolic rate, which means more calorie-burning throughout the day. So which type of exercise is best overall for changing body composition (less fat, more muscle)?
A study of 348 young adults examined the effects of aerobic versus resistance exercise on lean mass and fat mass in people of different fat categories (http://tinyurl.com/o8cbfzy). This was not a controlled study, but it does present a perspective worthy of consideration. Resistance exercise reduced fat mass and increased lean mass, whereas aerobic exercise only reduced fat mass. Anaerobic exercise was not examined.
More specifically, in “normal-fat” participants, either resistance or aerobic exercise decreased fat mass and increased lean mass. In “over-fat” and obese participants, resistance exercise reduced fat mass; aerobic exercise did not. The authors concluded that adults with excess body fat benefit most from resistance exercise.
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Mild cognitive impairment (MCI) is a syndrome that can affect memory, language, thinking and judgment. MCI doesn’t usually interfere with daily life, but people diagnosed with MCI are at an increased risk for developing Alzheimer’s disease or other types of dementia. Not everyone with MCI will develop dementia.
Some people have MCI as a result of a treatable mental health issue such as anxiety or depression, from a physical condition such as diabetes, high cholesterol, high blood pressure or obesity, or from side-effects of medication. Other risk factors include age and genes – which we can’t control – and behaviours such as smoking and heavy alcohol consumption. Controllable lifestyle factors such as a healthy diet and regular physical activity can influence brain health and cognitive abilities.
Is one type of exercise better than another for preventing dementia? A six-month-long randomized controlled trial of 86 women aged 70 to 80 with MCI examined the effects of aerobic and resistance exercise on cognition (http://tinyurl.com/pvkl7a7).
A previous 12-month-long study by the same authors found that twice-weekly resistance exercise significantly improved various cognitive abilities in cognitively-healthy women aged 65-75. The six-month study found that twice-weekly resistance exercise had a significant improvement in the participating women with MCI in just six months.
The authors believe that “twice-weekly strength training is a promising strategy to alter the trajectory of cognitive decline in seniors who already have mild cognitive impairment.”
The bottom line: Resistance exercise may be more effective than aerobic exercise for reducing body fat and improving brain health in certain segments of the population. Many people, especially females and seniors, tend to avoid resistance exercise. For improving overall health, regular resistance and aerobic exercise is a sure-fire combination. So get lifting and get moving!