1. Muscle helps manage blood sugar.
High-carb diets combined with sedentary lifestyles created an epidemic of diabesity (obesity and diabetes). About two-thirds of the population is overweight or obese, and prediabetic or diabetic.
Obesity and diabetes aren’t always paired together, however. About 20 percent of those with diabetes or prediabetes are at a healthy weight.
2. Muscle builds strength and stamina.
During your first few months of a weight-training program, you gain strength without much of an increase in muscle tissue. In this adaptation phase, your nervous and muscular systems get better at using the muscle you already have, even when you don’t have much.
You gain considerable strength without building any muscle. Then, after you’ve pushed your strength limits with your existing muscle, you start to build more muscle. After a few more months of consistent weight training and a high-protein diet, you notice a little more shape in your body, and your strength continues to improve.
3. Muscle supports your joints.
One of the primary reasons people avoid weight training is joint pain. Ironically, the reason many of those people have pain is that they don’t weight train. The better route is this: Figure out how you can weight train in a way that doesn’t make your joint pain worse. Eventually, weight training will alleviate your joint pain.
That’s not to say that someone with osteoarthritis in the knee, where there is no cartilage between the bones, will feel good doing squats. They might have to find an alternative movement.
At the same time, you don’t need to let anyone body part keep you from exercise altogether. There are plenty of areas you can work on. Interestingly, increasing lean body mass has been shown to improve some forms of arthritis.
4. Building muscle builds bone, too.
Physical tension or resistance stimulates the growth of muscle mass and bone density. After experiencing the stimulus, your body uses amino acids to build and repair muscle (along with other micronutrients) and uses protein, calcium, magnesium, and vitamins D and K to build bone. Although calcium, magnesium, and vitamin D and K are necessary for bone health, your body won’t build bone unless you give it a reason to. You have to stress your bone with resistance training.
5. Muscle helps you control body fat.
Muscle burns about three times as many calories per pound as body fat does. So, as you drop body fat and add muscle, your scale weight might not change, but you’ll create a significant shift in how you look while also increasing your resting metabolic rate.
Like muscle loss, the metabolic rate drops as you age.
Beginning in their 20s, the average person’s metabolic rate drops about two to three percent per decade. By age 50, it falls an average of four percent per decade. By the time you reach 70 years of age, your metabolic rate is about 30 percent lower than it was in your 20s. It’s important to note that if you’re doing a lot of cardio and eating a low-calorie diet to try to burn off excess body fat, you’re going to speed up the loss of muscle and slow your resting metabolic rate. Use cardio sparingly, and instead, rely on strength training and a high-protein diet to build lean body mass.
