Is your body suing your legs for nonsupport? If your legs look more like toothpicks than tree trunks, then you might have a higher risk of cardiovascular disease and premature death. Scientists discovered that body shape influences life expectancy and the risk of cardiovascular disease and diabetes. Overly skinny or obese people tend to die prematurely, as do those who carry excess abdominal fat.
A study by Berit Heitmann and Peder Frederiksen from the Copenhagen University Hospital in Denmark showed that men and women with a thigh circumference of less than 23 inches had an increased risk of premature death and heart disease. Larger thighs, however, provided no additional protection. The study examined nearly 3,000 men and women for 13 years. The results were independent of well-known heart disease risk factors, such as smoking and high cholesterol.
The researchers speculated that people with small thighs had less muscle mass in their lower body, which made them more susceptible to type 2 diabetes and insulin resistance. Small thigh circumference could be an early warning sign of cardiovascular disease. The Danish study only showed a relationship between skinny legs and premature death. They did not show that small leg muscles cause heart disease or that increasing thigh circumference will help you live longer. However, other studies found that weight training and aerobic exercise can increase leg muscle size, which improves metabolic health and blood sugar control.
Leg Muscles, Blood Sugar Control, and Premature Death
Carbohydrates are critical fuels, particularly for the central nervous system (brain and spine) and active muscle. The body prefers carbohydrates (mainly glucose— blood sugar) for fuel because it supplies energy more quickly than fats or proteins. However, high levels of glucose cause severe health problems. The hormone insulin is important for the movement of glucose into the cells. Glucose uptake is slowed when the cells are resistant to insulin (i.e., insulin resistance). Insulin resistance disrupts metabolism and increases blood sugar levels. It is linked to abnormal insulin signaling, blood clotting problems, and erectile dysfunction. It also triggers inflammation, which causes tissue damage, high blood pressure, abnormal blood fats, Metabolic Syndrome, cardiovascular disease, and premature death.
Muscle makes up about 35 to 40 percent of bodyweight and is the largest tissue in the body. It is the most significant site for glucose uptake. The muscles in the legs and hips are the largest in the body, so they play significant roles in blood sugar control and uptake.
The Danish study was not the first to notice the link between lower body muscle size and improved health. Emily Parker and colleagues from the HealthPartners Research Foundation in Minneapolis found that a greater hip circumference reduced the risk of diabetes and heart disease. Taiwanese scientists found that a smaller waist and larger thighs reduced the risk of diabetes and insulin resistance. These relationships were not affected by total fat. However, a large waist circumference was the best predictor of an increased risk of diabetes. The take-home message from these studies is that men can enhance health and longevity by increasing strength and muscle mass (particularly in the lower body muscles), decreasing abdominal fat, and increasing metabolic health through exercise.
Build muscle mass and strength if you want to live longer and prevent life-threatening diseases. A landmark study published in the British Medical Journal by Jonatan Ruiz from the University of South Carolina and colleagues found that good muscle strength was linked to a lower death rate from heart disease, cancer, and all causes in both young and older men. This 18-year-long study confirmed the results of other research showing that strong muscles increased longevity.
Strong muscles reflect good metabolic health. Stronger men can process carbohydrates, fats, and proteins more efficiently, regulate blood flow better, and have higher levels of muscle growth factors, such as testosterone, growth hormone, and IGF-I. Enhanced metabolic health boosts vigor, vitality, and sexual performance. Aging, physical inactivity, obesity, and poor diet trigger physical deterioration that eventually lead to degenerative diseases and death. While death comes to us all, strong muscles increase longevity and improve the quality of life.
People lose muscle mass and function as they age, particularly in the lower body. Muscle loss destroys tissues vital to blood sugar control. Decreased muscle mass also reduces the capacity of cell energy centers called mitochondria. Canadian and American scientists, led by Simon Melov, found that six months of weight training improved the function of these cell energy centers. At the beginning of the study, older adults were 59 percent weaker than young adults. Weight training reduced the deficit to 38 percent. Gene activity associated with age-related mitochondrial function increased dramatically. Cell function in the older adults reverted almost to young adult levels. The study showed that weight training turned back the clock on cellular aging.
Increasing lower body muscle mass through weight training improves blood sugar regulation by increasing insulin sensitivity. Insulin moves glucose (sugar) from the blood into the cells, and promotes glycogen formation (stored carbohydrate), protein synthesis, and fat storage. As discussed, poor blood glucose regulation is linked to the Metabolic Syndrome, a group of health problems that include high blood pressure, abdominal fat storage, abnormal blood fats, inflammation, type 2 diabetes, and blood clotting abnormalities. It also decreases the capacity of blood vessels to release nitric oxide, which is vital for controlling blood flow throughout the body. Erectile dysfunction, caused in part by inadequate nitric oxide production, is an early warning sign of the Metabolic Syndrome and insulin resistance. Weight training and increased strength improves insulin function, which is an important marker of metabolic health.
Build Leg Muscle for Increased Health and Longevity
Muscle mass is a critical tissue for metabolic control and health. The muscles in the legs and hips are the largest in the body, so strengthening and conditioning them will have the greatest impact on metabolic health. Increasing muscle mass in the lower body will also make it easier to lose abdominal fat because you will have a greater capacity for high-intensity exercise, which burns more calories. A basic strategy for increasing strength and muscle mass in your legs and hips includes:
The combination lower-body weight training and aerobics reduces the risk of death from cardiovascular disease, cancer, and all causes. Do at least 30 minutes of moderate-intensity aerobic exercise five days per week. Also, do large-muscle weight training exercises two to four days per week. Examples of exercises to build lower body muscles include back squats, front squats, kettlebell swings, lunges, step-ups, leg presses, knee extensions, and leg curls. Work hard to trigger rapid changes in leg circumference, overall muscle mass, and strength.
Lift weights before doing aerobics to maximize strength and muscle mass; doing aerobics first will cause fatigue and cut down on your ability to build lower body muscles.
Check your hormones. Men over 40 sometimes have anabolic hormone deficiencies and could benefit from hormone supplements. Studies by Shalender Bhasin from Boston University and colleagues showed that the capacity for muscle hypertrophy (growth) and strength is linked to blood testosterone levels. It is not clear whether the relationship between strength and longevity is due to muscle capacity or anabolic hormone levels.
Consume enough protein. Many aging men don’t consume enough protein in their diets, which causes muscle loss. Most studies show that active men should consume 1 to 1.7 grams of protein per kilogram of bodyweight per day, to optimize muscle mass and prevent protein breakdown.
We don’t know if increasing leg circumference will make you live longer or prevent diabetes and heart disease. We know that increasing strength, fitness, and muscle mass will improve metabolic health and have a positive impact on your life.
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