Could there be a scientific reason people love peering into fish tanks in waiting rooms? Researchers say watching real fish swim around in aquariums and tanks may actually provide physical and mental health benefits.

The study included experts from the National Marine Aquarium, Plymouth University and the University of Exeter.

The team assessed people’s physical and mental responses to fish tanks. They found that viewing an aquarium display led to a reduction in blood pressure and heart rate. They also found that having a larger number of fish in an aquarium helped not only to hold people’s attention for longer, but also improved their moods.

This study specifically looked into how underwater settings could impact health in humans. In previous studies, other scientists have noted how spending time in various natural environments has been shown to be beneficial to people.

The researchers conducted their study at the National Marine Aquarium when it refurbished a 550,000-liter tank, one of its main exhibits. As part of the renovation, the aquarium also began introducing new fish species.

The scientists then assessed the mood, heart rate and blood pressure of participants over time as the number of fish in the revamped exhibit gradually increased.

One of the experts said that while aquariums usually focus on educational factors, people who experience higher work stress and live in crowded urban areas may benefit even more from aquariums by providing access to nature.

So the next time you notice a fish tank in a waiting room, spend some time gazing into its depths at the under the sea world. Who knows? It could just lift your spirit and improve your health, too.