CASSELBERRY, Fla. -

Dawn Jensen is attached to her smartphone.  

                  WEB EXTRA: SENSORY DEPRIVATION STUDY

As a social media trainer, she's constantly doing research and keeping in touch with clients.  When it comes time to sleep at night, it is hard for her to disconnect.

"I do have trouble sleeping at night because I have a hard time turning off electronics and a hard time turning off my brain," she said.

When Jensen spent an hour inside a sensory deprivation flotation tank in complete darkness, she said she experienced relaxation like she'd never felt before.

"Sometimes just an hour by yourself of alone time, can really help you get caught up on yourself mentally," said Derek Hudiburgh, who owns Total Zen Float in Casselberry.

He compared the physical benefits that clients get from floating to how you might feel after a massage, except at a better price. 

An hour in a tank at Total Zen Float costs just $45. 

Hudiburgh and his business partners purchased their two flotation tanks and opened the small spa of sorts in the fall.

The rooms are dimly lit and each equipped with a shower.  Clients shower before and after entering the 150 gallon tanks which are filled with 10,000 pounds of Epsom salts.  

The tanks are then filtered three times in between each client, who floats completely nude. 

The salt creates a buoyancy which means the participant does not have to hold up any muscles and can completely let go.

Sensory deprivation flotation tanks originated in the 1950s when an unconventional psychologist named John C. Lily invented them to experiment with LSD. 

Lily reportedly spent a great deal of time floating in his sensory deprivation tank in a drug-induced state.  

It wasn't until another psychologist, Peter Suedfeld, began using the tanks for more conventional studies on stress and relaxation that the idea became mainstream.

By the 1980s the  Dallas Cowboys were using a sensory deprivation tank the team dubbed the "think tank." Players would float one at a time for an hour, and then after their minds were completely cleared they would watch video of game plays. 

Swedish researchers at Karlstad University started studying sensory deprivation in flotation tanks in the 1990's and found that people experienced pain reduction, stress reduction, and an overall sense of well-being. 

Participants in their studies also often reported having out-of-body experiences, and heightened senses after the sensory deprivation.

A researcher at the University of Pittsburgh even found that it can aid in muscle recovery after exercise. 

For Jensen, the experience allowed her to do something she hadn't done in years: take a nap in the middle of the day. 

After her float, she said she went home and fell right asleep.