Don't Take Muscle Loss for Granted - Live Longer, Get Stronger with Training

Beginning as early as age 30, your muscle mass begins to decline. 
As years go by, you may begin to look soft or flabby. These changes can start as early as your 30s, but most people see the more differences in their 40s and 50s. Unless you do something about it, you will lose about 1 percent of your lean muscle mass per year after age 40.
It doesn't have to happen. Only 30 percent of muscle loss is due to aging. The other 70 percent is up to you to maintain. Even if loss has begun, this percentage can be regained through strength training.
If you want to start a program, get your doctor's OK first. Consider scheduling time with a certified trainer or physical therapist who can help you design a routine, especially if you are a beginner or have health issues.
At the start, take it slow. The goal is to gradually and consistently improve over time. Always begin with five to 10 minutes of gentle exercise to warm up your muscles.
  You can do strength training at home or in the gym. Consider using:
 * Your body weight to do exercises such as push-ups, sit-ups, leg squats, or side and back strengthening exercises.
 * Resistance tubing, which can be found at sporting goods stores and department stores.
 * Free weights, such as barbells or dumbbells. Start with light weights.
 * Weight machines.

Mayo Clinic studies show these to be some of the benefits:
Stronger bones. Strength training increases bone density and reduces your risk of osteoporosis.
Weight control and fat reduction. Muscle burns calories, making it easier to reduce body fat and control your weight.
Fewer injuries. You will have better balance, coordination and agility. Your joints will be more stable and will be able to give muscles a greater role in absorbing stresses on joints. 
Less back pain. Strengthening the lower back muscles is a proven way to ease back pain.
Better brain activity. Studies show that strength training and exercise improve cognitive function.