16. Chronic fatigue
Feeling tired is probably among the symptoms that are ignored most often. It’s easy to ignore. Busy schedules, lack of sleep, and stress are just a few of the many common factors that make people feel exhausted. But chronic fatigue — especially when it comes with other unusual signs like unexplained weight loss — can be a symptom of several serious health problems, including cancer, a thyroid disorder, or anemia (low counts of red blood cells in the body).
Chronic fatigue can also be an early sign of heart attack in women, according to a study published in Circulation: Journal of the American Heart Association. The study of more than 500 women found that unexplained fatigue or trouble sleeping were frequently experienced as much as a month before the heart attack. These are 28 dangerous things experts link to heart disease.
17. Sharp pain in your sides
Though a sharp pain on the side, commonly referred to as side stitch, can occur while exercising, at other times it might be coming from the kidneys. You may feel it like a dull, one-sided ache in your upper abdomen, side, or back, according to the Mayo Clinic. It may be an infection, which would usually come with fever, or stones, cysts, and even cancer.
18. Swollen legs
Swelling in the feet is often caused by fluid retention, or edema — when water stays in the circulatory system. Most of the time the reason is high sodium intake — and that’s why it’s among the “resolutions” doctors want people to keep. But swollen legs may also indicate a more serious problem such as kidney failure. The kidneys are responsible for overall fluid balance in the body, so when they are not functioning properly, fluid can build up.
Swelling can also be a symptom of deep vein thrombosis (DVT), also a potentially very dangerous condition occurring when blood clots form in a large vein. If the clot bursts, it can travel to the lungs, causing an embolism, which can be fatal.
19. Profuse sweating
When excessive sweating is caused by a medical condition, it’s called secondary hyperhidrosis. These conditions include diabetic hypoglycemia (low blood sugar level), a heart infection, heart attack, leukemia, or a thyroid disorder (which can also be among the causes of memory loss).
Hives, swelling, and other skin reactions, are well known as symptoms of food allergens. Vomiting is a lesser known sign that an allergic reaction has occurred, Elliott said. “The GI tract is lined with allergy cells that can get activated in the setting of an allergic reaction,” she added. “It usually happens quickly (within minutes to an hour) after eating the food.”
Vomiting, especially when throwing up solid food shortly after eating and when it’s accompanied with nausea, may be a sign of stomach cancer.