First proposed in 1989, the “hygiene hypothesis” is dated – and dangerous, potentially confusing the public and possibly adding to the spread of infectious disease. Generally, the hypothesis suggests that reduced exposure to childhood infections contributed to the rapid rise in childhood allergies. In short, we had become too clean, too hygiene-conscious. Despite the scientific community realizing rather quickly this contention oversimplified a more complex series of events, the term even today is bandied about carelessly to the detriment of many.

A robust, well-functioning immune system is a result of a combination of factors, beginning even before birth and continuing throughout a lifetime. Maternal milk, diet, exercise and exposure to friendly microbes are some of factors that contribute mightily to successful immune responses.

From Medical Xpress, Microbiology Society: “Researchers now agree that a range of lifestyle changes, including an increase in Caesarean section (C-section) births, less breast-feeding, smaller family sizes, and less time outdoors are underlying causes of reduced exposure to friendly microbes, whilst altered diet and antibiotics have adverse effects on the composition of the microbiome.” Professor Graham Rook (University College, London), agrees: “It isn’t really hygiene. The common infections of childhood measured by hygiene are designed to combat ‘crowd infections’ that appeared much too late in our evolutionary history to have evolved into an essential role in the development of human immune systems. The organisms that we evolved to require are the microbiota of our mothers, and organisms from the natural environment. Continuing to call it the hygiene hypothesis leads people to interpret more recent findings in a way which is quite wrong.”(Read more here).

Here are two more pieces that address the shortcomings of the “hygiene hypothesis” and clear up some misconceptions:

Exercise immunology is relatively new, but studies that begin to demonstrate the connection between physical activities and improved immune response date back more than a century:

The immune system is critical to our defense against a host of environmental dangers that we are exposed to every day. It is important that it distinguishes between real threats while not overreacting to harmless interventions. And it is as important as ever to avoid needlessly challenging our systems by maintaining good hygiene, and keeping at bay as best possible infectious agents that lead to the spread of disease.