Silhouette of back of a student sitting on a bench, under a shade tree, looking out at lake in the UC Davis Arboretum
(Gregory Urquiaga/UC Davis)

Viewing Water Outdoors Slows Heart, Lowers Blood Pressure

Study done at the UC Davis Arboretum finds similar health benefits to ‘forest bathing’

The next time you feel your heart racing and your blood pressure rising, try this: Go outside and gaze at a body of water. Research by a UC Davis psychologist suggests that contemplating water — even if it’s a swimming pool — may be good for psychological well-being.

In a pair of studies, Richard Coss, professor emeritus of psychology, and a former student, Craig Keller (B.A., psychology, ’09), measured the heart rate and blood pressure of people after they gazed at different outdoor scenes for one minute, 40 seconds at a time.

In the first study, 32 participants showed reduced average heart rate and lower blood pressure (systolic/diastolic ratio) after looking at a swimming pool than they did after viewing a tree in a parking lot or a street sign.

In the second, 73 people visited a series of sites along the UC Davis Arboretum. Blood pressure and heart rate, on average, were lower when participants looked at the Arboretum waterway than when they viewed the adjacent ground. The wider the body of water — in the broader stretch of the creek channel and the Arboretum’s two small lakes — the more pronounced the effect was.

Their findings were reported in a recent online article in the Journal of Environmental Psychology.

Fosters feeling of relaxation

In the second experiment, participants reported feeling more relaxed when they viewed the water that also correlated with their lowered blood pressure. They reported being more relaxed when looking at the ground next to the wider parts of the waterway as well.

Paradoxically, people reporting higher levels of relaxation experienced faster heartbeats at some of the testing sites — especially when viewing wider sections of water. Coss said that could reflect the feeling of elation, an emotion which can raise heart rate. “It is plausible that the participants in our study misinterpreted their joy of observing the wider sections of water with enhanced relaxation,” he said.

The cardiovascular and psychological benefits of brief periods of gazing at water are temporary, Coss said, and further study is needed on whether sustained viewing would have more lasting benefits.

An evolutionary benefit

Coss, whose research focuses on how evolution influences human behavior and neurobiology, has long been interested in the physiological and mood-enhancing effects of viewing water.

In studies in the late 1980s, he found that pictures of landscape scenes with water could potentially enhance the living experiences for astronauts in the then-planned International Space Station, as it had in another study he conducted of scientists overwintering at Antarctic research stations.

In later research, he showed that humans perceive glossy and glittery paper as wetter than matte or rough surfaced paper, and that infants are more likely to mouth glossy plates than dull ones. Those studies suggest that water perception is partially innate and likely reflects a long period of natural selection for the ability to detect water.

Yet, while other studies have looked at the physiological benefits of “forest bathing,” or viewing plants and trees while walking through the woods, the effects of viewing water outdoors had not been explicitly tested before his most recent experiments, Coss said.

He said the findings could be applicable to landscape design as well as public health.

— Kathleen Holder, content strategist in the UC Davis College of Letters and Science


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