Why is it that drinking on a boat makes you feel drunker than when you're on land?
We asked Dr. Jeahan Collettie, an emergency medicine expert at the Mayo Clinic, for her expert opinion. Here's an abridged version of what she emailed us.
Why does motion on a boat make people feel drunker than if they are on land?
"The rocking motion of a boat slows down brain wave activity, causing a person to feel more sleepy or fatigued. It has a similar effect to rocking a baby to sleep. Motion can also cause a person to become dizzy or disoriented due to problems with the balance (or vestibular) system of the body, which is adjusted to being on still land and has difficulty quickly adjusting to unanticipated movement. This sleepy and dizzy feeling will cause a person to feel more drunk than on land," Collettie wrote.
She said it's not just the motion though. The combination of noise, vibration, sun and wind enhances that feeling – a phenomenon she said is often referred to as Boater's Hypnosis. Being in the hot sun can lead to dehydration as well, which then causes fatigue and can contribute to the drunk feeling.
What makes this so dangerous?
Alcohol accelerates these effects, which leads to impaired coordination, judgment, reaction time, and vision, she wrote.
And research has shown it takes one-third the amount of alcohol to make a person have the clinical effects of intoxication while on water, compared to on land.
Impaired coordination can making operating a boat less safe, especially since there aren't lanes and the captain usually isn't very experienced. Passengers could be more likely to fall into the water and get hurt – or drown. And alcohol can screw with your peripheral vision and the ability to distinguish certain colors, which increases the risk of hitting something.
"Because alcohol depresses the central nervous system, it makes it more difficult for the driver to process information and react to potentially dangerous situations. Hidden dangers will be far less apparent to a driver who is under the influence of alcohol," Collettie wrote.
How does drinking while swimming affect people?
"Swimming can be extremely dangerous in people who are intoxicated," she wrote. "When swimmers get water in their ears, this can disturb the inner ears, which play an important part in the balance system of the body. This can lead to disorientation, which is aggravated by alcohol. Disorientation in the water places a person at risk for drowning."
Being drunk also makes it harder to perceive the current. And if an intoxicated swimmer gets swept away, they're "at greater risk of hypothermia (due to prolonged water exposure and lowered body temperature caused by alcohol) and drowning (due to an impaired ability to swim secondary to fatigue)."
Drunken swimmers are also more likely to swim where it's not safe. Think near a boat propellor, for example, she said.
What are some tips for people to stay safe while boating and drinking?
"The best way to stay safe on a boat is to avoid bringing any alcoholic beverages. Even boat passengers are at risk due to more risky behavior from impaired judgment and the potential to fall in the water from lack of coordination," Collettie wrote.
She said if a boater does want to drink the safest option then is to do it while docked or ashore. And whoever is driving should wait at least an hour per drink consumed before operating the boat again.
Also: Bring lots of non-alcoholic beverages to stay hydrated, since that's "one of the most important things a boater can do to combat the fatigue that can result from the dehydrating effects of the heat and sun," she said.
Make sure to wear light clothing and put on sunscreen to protect yourself from the rays as well.