4. Are you lonely tonight? There is a growing body of research that demonstrates how loneliness may affect your health. And a 2013 study demonstrates that our friendships and social networks have been in decline lately. The result could be more loneliness in our lives.

One study found that people with strong social relationships survived longer than those without. The risk factor was comparable to twice that of being obese or smoking 15 cigarettes a day. Loneliness was linked to depression and high blood pressure.

One theory on loneliness and its ill effects on the body is that it could make one feel chronically threatened. It is similar to being stuck in “fight or flight” mode, which releases chemicals in the body that can damage it over time. Basically, an always “on” immune system wears itself out. It has been noted by researchers that the physiological response of the brain to social isolation is to find the situation threatening to survival. Since humans are social animals, this makes sense.

5. Toxic Shock Syndrome (TSS). This condition is commonly associated with tampon use, but also may be caused when the S. aureus, staph, bacteria enters a wound. It can also be found among menstruating women who use birth control sponges, diaphragms or cervical caps. TSS can occur after childbirth, a bout of the flu, chickenpox, surgery, or any break of the skin like cuts or wounds.

Because TSS causes a sudden release of poison into the bloodstream from an overgrowth of staph, symptoms include a sudden fever over 102 degrees F, low blood pressure and a rash that looks like sunburn. Other signs include severe flu-like symptoms such as a headache or sore throat, muscle aches.

People who die from TSS suffer hypotensive shock, followed by the cessation of heart and lung functioning.

So now you know about five diverse conditions that could be deadly without a little knowledge. Though all may seem innocuous, they may cause permanent, life-threatening damage.