Maintaining a healthy weight is more difficult as you get older. As you get older, your muscle mass decreases and body fat takes its place. Since fat tissue burns fewer calories than does muscle, you need fewer calories to maintain your current weight.
As you age, your heart rate becomes slightly slower and your heart might become bigger. Your blood vessels and your arteries also become stiffer, causing your heart to work harder to pump blood through them. This can lead to high blood pressure (hypertension) and other cardiovascular problems.
Bones, joints and muscles
With age, bones tend to shrink in size and density — which weakens them and makes them more susceptible to fracture. You might even become a bit shorter. Muscles generally lose strength and flexibility, and you might become less coordinated or have trouble balancing.
Constipation is more common in older adults. Many factors can contribute to constipation, including a low-fiber diet, not drinking enough fluids and lack of exercise. Medications — such as diuretics and iron supplements — and certain medical conditions — such as diabetes and irritable bowel syndrome — also might contribute to constipation.
Reprinted from Mayo Clinic article: