Influenza, more commonly called the flu, is a viral infection that affects up to 25 to 50 million people each year, according to experts at the Flu Facts. Influenza is highly contagious, spread by droplets breathed or coughed into the air.

The size of your pupils fluctuates dozens of time during the day in response to changing light. Assuming you're not exercising in the dark, some other factor is at play if your pupils are dilated during a workout.

Improperly prepared, stored and/or served food products can attract bacteria or germs that can lead you to a very unpleasant condition: food poisoning. While vomiting is one of the most common food poisoning symptoms, certain bacteria known to cause food poisoning can lead to sore throat and flu-like symptoms.

The idea that you must keep a baby awake after a head injury to prevent a coma is actually an old wive’s tale.

Iron, a mineral that helps form red blood cells and carries oxygen through your body, is essential -- within limits. Too much iron can harm the organs that store it, especially the liver, a major storage unit for iron. Ferritin is a protein found within cells that stores iron.

Cramping from eating beets is not common and may be related to a digestive condition. Although stomach cramps are not always a sign of a more serious condition, talk with your doctor for an evaluation to determine the cause.

Teething is an obviously painful stage of development for babies and toddlers. The pain of teething may precede the actual eruption of the teeth for days or weeks. This can confuse and unnecessarily worry parents. Their baby or toddler is in obvious pain, but there is no evidence of anything out of the ordinary.

Cialis, generic name tadalafil, is a medication prescribed for the treatment of erectile dysfunction in men. Because the medication helps to increase blood flow, it also can be effective reducing symptoms associated with pulmonary artery hypertension including reducing dizziness, shortness of breath and tiredness.

Sitting down to enjoy a meal can be ruined if you develop pain under your ribs. Discomfort, burning and pain under your ribs is a common sign of various conditions, such as indigestion, heartburn, a peptic ulcer and a severe allergic reaction.

Glucose is required by the body to maintain life. However, it is possible to have too much of a good thing. Hyperglycemia, or high blood glucose levels, may be due to diabetes, medications, stress, illness, hyperthyroidism, Cushing syndrome, pancreatitis or pancreatitis cancer.

Melatonin is a hormone made by your brain that helps regulate your body's internal clock. Your levels of melatonin increase at night and decrease during the day. Some people find that taking melatonin supplements helps them to sleep better, especially if they are suffering from jet lag.

The hip flexor muscles lie under your abdominal muscles. A group of muscles that includes the psoas major and minor, iliacus, sartorius and rectus femoris, the hip flexors connect your thighs to your pelvis. When they contract, these muscles bring your thigh and torso closer together.