Riding a bike gives you a substantial workout. I enjoy riding bike trails because I get to enjoy nature while getting low-impact exercise. I gave up riding on streets because there are too many dangers posed by cars and trucks. If you don’t want to ride outdoors, you can pedal a stationary bike indoors.

Most xerostomia is related to the medications taken by older adults rather than to the effects of aging. More than 400 medicines can affect the salivary glands. These include drugs for urinary incontinence, allergies, high blood pressure, depression, diarrhea and Parkinson’s disease.

Lactase is an enzyme made in the small intestine. You need lactase to digest lactose, the sugar in milk. People who are lactose intolerant don’t make enough lactase; after consuming lactose, they suffer from bloating, nausea, stomach cramps and diarrhea.

First, a bit of biology ... The lens in the front of your eye focuses light on the retina in the back of your eye. The lens is like the one in a camera, and the retina is like film. The space between the lens and retina is filled with the vitreous, a clear gel that helps to maintain the shape of the eye.

Riding a bike gives you a substantial workout. I enjoy riding bike trails because I get to enjoy nature while getting low-impact exercise. I gave up riding on streets because there are too many dangers posed by cars and trucks. If you don’t want to ride outdoors, you can pedal a stationary bike indoors.

TIA stands for “transient ischemic attack.” A TIA is an interruption in the flow of blood to a part of your brain. Its symptoms are the same as for a stroke. A TIA lasts anywhere from minutes to many hours. It goes away and leaves no apparent permanent effects.

Doctors say you have high blood pressure if you have a reading of 140/90 or higher. A blood pressure reading of 120/80 or lower is considered normal. Prehypertension is blood pressure between 120 and 139 for the top number, or between 80 and 89 for the bottom number.

The techniques I will mention here should not substitute for seeing a doctor about a medical problem. Relaxation techniques are generally considered safe for healthy people, but you should tell all your health-care providers about relaxation methods you are considering.