The Joy of Cleanliness: Why It Feels So Good

To bring a bit more happiness to someone special, consider cleaning their car, tidying their workspace, or refreshing their bed with clean sheets. These thoughtful acts not only earn appreciation but also offer tangible biological and psychological advantages. Humans naturally perform better in orderly settings, while disarray can trigger a chain reaction of stress and negativity.

Morgan Brashear, a home care expert at Procter & Gamble, highlights in an email the dual pressures people face regarding cleanliness. "Internally, a messy or cluttered space can make you feel disorganized and overwhelmed," she says. "When life feels chaotic at work and home, maintaining cleanliness helps restore a sense of control." Externally, she adds, we worry about others' opinions of our spaces, fearing judgment about our cleanliness and organizational skills. This means we not only judge ourselves harshly but assume others do the same.

A Modern Standard of Clean

Why are we so focused on cleanliness? This trend largely stems from progress over the past couple of centuries. "The emphasis on cleanliness is a relatively recent phenomenon, driven by breakthroughs in sanitation, hygiene, and technology. Today, high cleanliness standards are considered basic, whereas they would have been excessive a hundred years ago," explains Dr. Amesh Adalja, an infectious disease expert at the Johns Hopkins Center for Health Security.

These advancements have significantly reduced the spread of serious infectious diseases, particularly in developed nations. However, Adalja points out that achieving complete sterility is nearly impossible. "Cleanliness reduces the presence of harmful organisms, but true sterility is unattainable in daily life because microorganisms are everywhere," he says. "Most microbes are benign or even beneficial. Problems arise only in specific situations, such as contaminated food or water."

The Nose Knows

Most people don’t inspect their homes with microscopes to detect issues. Instead, we depend on our senses. While sight is important (it’s hard to overlook a pile of dirty dishes), smell is often the first to detect unpleasantness. Brashear explains that people typically check clothes for stains visually, and if they look clean, they rely on the tried-and-true "sniff test" to confirm freshness.

The nose is uniquely linked to the brain's hippocampus and amygdala through the olfactory bulb, which begins in the nose and extends into the brain where scent receptors are located. This direct connection means certain smells can evoke powerful memories, such as the comforting feeling of being tucked into freshly washed sheets by your mother, promoting a sense of calm and happiness.

"Each home has its own distinct scent," Brashear explains, highlighting that air is a mix of various odor molecules from laundry, hair products, lotions, cooking, pets, and other sources. She notes that odor molecules circulate continuously, especially in closed environments during extreme weather. These molecules settle into furniture, carpets, and curtains, only to be released again when disturbed or when humidity levels rise. Brashear emphasizes the importance of cleaning the air effectively, using products that neutralize odors rather than just covering them up. "Air occupies over 75 percent of your home's space, yet it’s often overlooked in cleaning routines," she adds.