While your nose picks up the chemicals that create aromas, it's your brain that actually tells you what you smell. That's one reason that patients who suffer from Alzheimer's disease and other neurological disorders sometimes experience a loss of their olfactory abilities [source: Doty].
What's even more surprising, though, is that mental illness can make you believe that you smell terrible, even if you don't. Olfactory Reference Syndrome is a psychiatric disorder characterized by a false belief that you have a bad body odor. Eighty-five percent of people with the disease report that they actually can smell their own imaginary stink [source: Phillips and Menard].
Author's Note: 10 Sources of Body Odor That Aren't Just Sweat
You may have heard this one already, but if not, there's the famous story about Samuel Johnson, the 18th-century British poet and essayist. On a summer day in London, he paused to sit down on a park bench because he was perspiring so heavily. A young woman next to him complained that he smelled. "No Madam," he replied. "You smell. I stink."
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- Newitz, Annalee. "Birth control pills make females smell "wrong" to males." Io9.com. July 29, 2010. (May 10, 2014) http://io9.com/5599793/birth-control-pills-make-females-smell-wrong-to-males
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- Phillips, K.A. and Menard, W. "Olfactory reference syndrome: demographic and clinical features of imagined body odor." General Hospital Psychiatry. July-August 2011. (May 10, 2014) http://www.ncbi.nlm.nih.gov/pubmed/21762838
- Science Daily. "Body odor changes following vaccination." April 2, 2014. (May 10, 2014) http://www.sciencedaily.com/releases/2014/04/140402211946.htm
- Science News. "Lemurs on Contraceptives Don't Smell Right." July 28 2010. (May 14, 2014). http://www.americanscientist.org/science/pub/lemurs-on-contraceptives-dont-smell-right
- Sifferlin, Alexandra. "'Old-Person Smell' Really Exists, Scientists Say." Healthland.time.com. May 31, 2012. (May 10, 2014) http://healthland.time.com/2012/05/31/old-person-smell-really-exists-scientists-say/
- Watson, Stephanie. "Can What You Eat Make You Sweat?" WebMD. (May 10, 2014) http://www.webmd.com/skin-problems-and-treatments/features/what-you-eat
What if you're sweating and you're not exercising or experiencing hot weather? Learn what conditions can make you sweat too much at HowStuffWorks.