Two heat-related deaths have occurred in San Jose since the start of the current heat wave, Santa Clara County officials said Wednesday.

The county coroner confirmed the deaths were caused by hyperthermia Monday, and a third death was confirmed Tuesday. The victims were identified as 72-year-old Dennis Young and 87-year-old Setsu Jordan. A third person's death was confirmed Tuesday, but the Santa Clara County coroner has not yet specified whether it was caused by the heat.

"It is tragic when someone dies of hyperthermia since in most every case it could have been prevented," said Dr. Michelle Jorden, of the county Medical Examiner-Coroner’s Office. "Hyperthermia and heat stress happen when a body’s heat-regulation system cannot handle the heat. It can happen to anyone, which it is why it is so important to be in a cool location, drink plenty of water and take a cool bath or shower if you are getting too hot."

A National Weather Service excessive heat warning is in effect until 9 p.m. Thursday. High temperatures are forecast to range from 90 to 100 degrees across most of Santa Clara County, with hotter temperatures possible, forecasters said.

For a list of Cooling Centers and information on heat-related illnesses and prevention, visit the County of Santa Clara Office of Emergency Services website or call 211.

Additional tips for those who must work or exercise outdoors:

Ensure that cool drinking water is available.

Drink water or electrolyte-replacing sports drinks often; do not wait until you are thirsty.

Avoid drinking sweetened drinks, caffeine, and alcohol.

Avoid drinking extremely cold water as this is more likely to cause cramps.

Allow athletes or outdoor workers to take frequent rests.

Older adults and individuals with chronic medical conditions:

During peak heat hours stay in an air-conditioned area. If you do not have access to air conditioning in your home, visit public facilities such as cooling centers, shopping malls, parks, and libraries to stay cool.

Older adults and those on certain medications may not exhibit signs of dehydration until several hours after dehydration sets in. Stay hydrated by frequently drinking cool water. If you’re on a special diet that limits liquids, check with your doctor for information on the amount of water to consume.

Stay out of the sun if you do not need to be in it. When in the sun, wear a hat, preferably with a wide brim, and loose-fitting, light-colored clothing with long sleeves and pants to protect against sun damage. And remember to use sun screen and to wear sunglasses.

Infants and Children:

It is illegal to leave an infant or child unattended in a vehicle (California Vehicle Code Section 15620).

Infants and young children can get dehydrated very quickly. Make sure they are given plenty of cool water to drink.

Keep children indoors or shaded as much as possible.

Dress children in loose, lightweight, and light colored clothing.

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