Our bodies are very complex machines and have their own ways of signalling when something is wrong. If we’re stressed, our eyes, skin and hair tend to be a dead give-away and it appears that our ancestors were very stressed indeed.
A recent study of the hair from ancient Peruvian remains found high levels of the stress hormone, cortisol. It is the first study to detect cortisol in ancient hair and has been accepted for publication in the Journal of Archaeological Science.
Cortisol is produced in response to real and perceived threats, but the pressures of modern day living are thought to be contributing to prolonged levels of stress. Once released, cortisol travels to nearly every part of the body, including to blood, saliva, urine and hair. The high levels of this hormone found in the hair of ancient Peruvians suggest that humans who lived in that area between 550 A.D. and 1532 were under more stress than we are today.
Lead author of the study Emily Webb, an anthropologist from the University of Western Ontario, said there are many possible reasons that stress levels would have been high but they’re hoping to pinpoint what exactly might have caused such levels of stress in the early Peruvians.
“Food availability, drought conditions and nutritional stress” could have contributed, Webb said. “[And threats] to physical or social integrity, i.e., health, safety and well-being.” But, she said, since nitrogen and carbon isotopes present in hair permit reconstruction of ancient diets and certain physiological and metabolic states, they may be able to get a better idea of the situations the early Peruvians were in.
Researchers measured cortisol in hair from 10 individuals buried at five different sites in Peru and also found the stress hormone in hair from early Ontario residents, ancient Nubians and early Egyptians, although it was the Peru residents that were the focus of this study.
Webb says that while the stress levels of these Peruvians were higher on average than levels measured for member of today’s society, the comforts of modern living may not be able to erase human stress.
“A society serves as a protective buffer, and while our society effectively protects us from, for example, extreme year-to-year differences in food availability, as individuals, we still experience considerable stress in our lives for other reasons,” she said.
In fact stress is often the trigger to a number of ailments, including hair loss. Hair grows at an average rate of about a quarter of an inch per month, but stress can alter the hair growth cycle. Depending upon the individual’s hair length, researcher said they were able to trace stress levels up to 27 months before the Peruvian people died.
This latest research may mean we could soon know not only how our ancestors lived and behaved, but also how they felt.