Muscle plays a significant role in your long-term health, fitness, longevity, and even your ability to ward off disease and infection.

Yet the vast majority of Americans do little to no strength training.

Investing three to five hours per week, lifting weights and doing other movements that challenge your muscles, bones, and connective tissue is one of the healthiest activities you could take part in.

Provided people follow a well-designed strength training program, the benefits of muscle mass go way beyond aesthetics.

1. Muscle builds your quality-of-life savings account.

Muscle is your quality-of-life savings account. The more you have as you enter later adulthood, the longer you’ll be able to carry on the activities you love to do today.

Without consistently putting your muscles under sufficient stress, they get smaller. It would be like hoping you build a big financial nest egg, but never put any money into your retirement account. To build the next egg, you have to exercise discipline with your spending, and set money aside.

To build a quality-of-life savings account with muscle, you have to...well...exercise.

Throughout your life, you'll face injuries and physical setbacks that keep you from exercising. You might also get cancer, or develop heart disease, which causes cachexia. The more you have when that happens, the more you can afford to lose before facing serious health problems.

Muscle mass is an independent predictor of all-cause mortality in older adults. The more muscle mass you have, the lower your risk of dying.

Read also: How much protein do I need to build muscle?

2. Muscle mass increases your carbohydrate capacity.

The only places you store carbohydrates are in your liver and skeletal muscle. You're not going to increase your liver's size, so building muscle is the only way to improve your carbohydrate capacity.

If you have diabetes or insulin resistance, talk to your doctor about following a ketogenic diet for a while. If your doctor says a ketogenic diet doesn't help with diabetes, find a different doctor. But even with a change in diet, it's imperative to start strength training.

Type II diabetes and muscle loss create a vicious cycle. The more muscle you lose, the more likely it is that you'll develop type II diabetes. The worse your type II diabetes gets, the faster you lose muscle.

As muscle is the main organ of glucose disposal, reduced muscle mass leads to increased insulin resistance. Conversely, insulin resistance or T2DM (type II diabetes) itself is associated with accelerating loss of skeletal muscle, causing a bidirectional positive feedback loop between metabolic disorders and sarcopenia.

Kim JA, et al.

Though most people with type II diabetes are also overweight, about 20% of those with the condition are at a normal weight. A lack of muscle, whether you're overweight or not, is a significant factor in type II diabetes risk.

3. Resistance training improves heart health.

Strength training depletes oxygen in the blood. In the absence of oxygen, your contracting muscles produce lactate. Lactate causes your muscles to burn.

Your heart beats harder and faster to take the lactate away from and deliver more oxygen to your working muscles.

With continued strength training sessions, your stroke volume improves and your resting heart rate drops, which means your heart becomes more efficient.

Research also shows that resistance training improves the health of your blood vessels.

Strength training provides cardiovascular benefits similar to endurance training without the negative impact of increased inflammation, overuse injuries, elevated cortisol, or reduced testosterone.

4. Weight training increases bone density.

According to the National Osteoporosis Foundation:

A woman’s risk of fracture is equal to her combined risk of getting breast, uterine, and ovarian cancer

Men are more likely to break a bone due to osteopor...