Bob is driving a boat with a few friends on the lake. All have had a few beers. Suddenly, one of Bob's buddies stands up, tipping the boat and throwing him off balance and overboard. The friend hits his head on the side of the boat, but maintains consciousness and is retrieved from the water. He suffers a laceration, but his injuries could've been a lot worse.

Each year, thousands of people are injured or killed in accidents that occur when alcohol is mixed with summer activities. If you think it won't happen to you while you're boating, swimming, diving, biking, roller blading, walking, driving a car, or playing softball, here are some nationwide facts that might change your mind:

• Drinking may be a factor in as many as 80 percent of the 1,000 boating fatalities that occur in the United States each year, according to the National Transportation Safety Board.
• Alcohol is involved in an estimated 38 percent of drowning deaths, according to the National Institute on Alcohol Abuse and Alcoholism (NIAAA).
• The NIAAA reports that 40 to 50 percent of all diving injury victims consumed alcohol before their accidents.

During the summer, people often involve themselves in more vigorous activities and are more prone to injury. Alcohol slows reflexes, interferes with balance and coordination, and impairs judgment, so a situation you might be able to handle sober can become risky when you're intoxicated.

Typical injuries related to summer activities and alcohol consumption include falls, car and boating accidents, and pedestrians who have been drinking and are hit by cars.

Every year an average of 50 percent of boating fatalities involve alcohol, said Tim Smalley, boat and water safety specialist with the Minnesota Department of Natural Resources in St. Paul. "That means that one or more of the boat operators had been drinking at least one hour before the accident. In about 25 percent of fatality accidents, at least one operator was legally impaired (blood alcohol content of .10 or more)."

Unlike laws governing drinking and driving, boating laws "don't kick in until the boating operator is legally impaired," said Smalley. No state has an open-bottle law for boating, which means boat operators and passengers can drink while on the water. Thus, there is no open-bottle law for boat passengers who fall overboard or capsize the boat, two common types of boating accidents. The typical boating death occurs in a small boat with a small motor and just two or three people, none of whom are wearing life jackets.

How is the body affected when you drink while boating, swimming, biking or just playing softball on a warm, sunny day? People who drink in hot weather are more susceptible to a number of problems, such as lightheadedness, dehydration, heatstroke, hypothermia, and blood pressure abnormalities.

Alcohol acts as a diuretic, meaning it saps the body of fluids. So alcohol combined with activity, such as playing softball, makes the body work that much harder. The combination can rapidly dehydrate a person and progress to the more serious heatstroke.

Impaired judgment caused by alcohol compounds the risks. Alcohol causes a loss of inhibitions and reckless behavior. For example, people misjudge swimming distances, how cold the water is, when it's time to get out of the heat, when the body is getting dehydrated, and when it's not safe to operate a boat or car.  Sunburn is another danger.

How much is too much? Studies have shown that in some people who have even one drink, performance starts to deteriorate in activities involving coordination and judgment. Impairment for boaters occurs at .035 BAC, or slightly less than two drinks within one hour for the average person, said Smalley.

Smalley and Sterner offer some simple rules to help avoid alcohol-related summertime injuries:

• Don't drink while involved in active recreation.
• If you drink, do so in moderation, and choose a designated non-drinker to operate a boat or car.
• Consider the risks before drinking and engaging in activity that requires judgment, reflexes and coordination.
• Avoid using alcohol during hot weather.
• Wear a life jacket. Nearly 90 percent of boating fatalities would be prevented if people wore life jackets.

--Published May 25, 1998