For the study, the researchers put 20 people in functional MRI (fMRI) scanners and asked them to rate the effort level required to
swallow small amounts of water under two different conditions — after exercising, when they were thirsty; and later, after they'd already drank about a liter of water.
Plus, the researchers found that people felt it was three times harder to
swallow a small amount of water after they'd consumed a liter of the liquid in comparison to when they actually felt thirsty post-exercise.