"Heat Finds Victims From Seashore to the Rockies."

This New York Times headline is from July 9, 1921, but could well have been printed any day this past week. On Tuesday, families from the Midwest to East Coast continued to endure a record-shattering, unrelenting heat wave.

"From Buffalo, Pittsburgh and Detroit came records of a mounting list of fatalities in which little children were most numerous among the victims," the Times reported that early summer day nearly a century ago.

Reports of infants and children dying in this summer's early heat wave have been documented in locales ranging from Kansas to Tennessee. And experts fear that increasingly frequent spikes in extreme high temperatures might bring such unwelcome news more often in the years ahead.

After the elderly, young people remain the most vulnerable to heat waves, which present direct dangers, such as heat stroke (especially if left inside cars) and burns from scalding playground equipment, as well as the more long-term harm of air pollution exacerbated by the rise in temperature.

A physically immature child may be less able to adapt to heat than an adult, researchers say.

"Especially at high risk is an infant wrapped up in a blanket," who is unable to tend to himself or tell an adult how he feels, said Jonathan Patz, director of the Global Health Institute at the University of Wisconsin, Madison.

Intense heat can pose problems even earlier in the game: A pregnant woman exposed to extreme temperatures might have a greater chance of having a baby of low birth weight, presenting risks for a range of future health problems and even learning disorders.

"We're not all equally vulnerable," Howard Frumkin, dean of the University of Washington's School of Public Health, said on a press call on Thursday.

According to the 1921 Times story, the New York Association for Improving the Condition of the Poor issued an appeal during the early July heat wave: "The oppressive heat of the last week has brought scores of mothers, with their babies and little children … pleading for a chance to go to the country or seashore."

Modern conveniences such as air-conditioning can make it less pressing for city dwellers to try to escape the oppressive heat concentrated in an urban setting. But those unable to afford air conditioners or who have lost power during last week's coincident severe storms have been more or less forced to cope as people did in the 1920s -- when officials opened up Central Park and piers as sleeping places for New Yorkers.

Nighttime lows, it turns out, might be more important than daytime highs.

"Low temperatures at night is exactly the way people are able to cope," Frumkin said. "As minimum temperatures rise, people lose that ability to get respite during evening hours and that's when you see health effects rising."

"I'm telling people that if they don't have A/C, to give their bodies four or five hours a day with some cooling -- even if that's at the mall or a cheap movie theater," said Daniel Satterfield, a TV meteorologist in Salisbury, Md. "If you let your body restore itself, then it can battle another 20 hours."

As one might expect, the longer the heat wave, the harder it becomes for people to ride it out safely without incident. And the earlier in the year that the extreme temperaturs strike, the less ready the body is to cope.

A 2010 study found that deaths during the first heat wave of a summer to be about double those in later heat waves.

"With repeated exposure to heat, the human body adjusts to better respond to heat, and this process typically takes one or two weeks of exposure to hot temperatures," the study's authors, Michelle Bell of Yale University and Brooke Anderson of Johns Hopkins University, told The Huffington Post via email.

Death is not the only health concern during a heat wave. Patz recently studied the a heat wave's effects in Milwaukee and saw an increase in the number of children and the elderly hospitalized for suicide attempts, as well as kidney disease and diabetes, probably related to dehydration.

Furthermore, heat waves generally bring more than just hot temperatures.

A baked Baltimore experienced dangerous smog this past week. High temperatures can speed up the formation of ozone and other airborne pollutants.

"The air pollution that often accompanies a heat wave is a risk factor for children with asthma," Patz said.

Plus, danger lurks when old coal-fired power plants are fired up to help power grids keep up with the demand from blasting air conditioners. Risks are also present in the smoke from raging wildfires out West, triggered by high heat, dry conditions and bark beetle devastation. Smoke from the Colorado fires has reportedly reached the Eastern Seaboard. Some scientists have predicted an increase in wildfires in the future as a result of global warning.

"Pollution levels can reach several times higher than a bad day in Mexico City or Beijing," Frumkin said.

The climate has already changed significantly since the 1920s, according to scientists. And forecasts call for ever harsher conditions in the decades ahead.

"What we are seeing is a window into what global warming really looks like," Michael Oppenheimer, professor of geosciences and international affairs at Princeton University, said during the press call. "It looks like heat. It looks like fires, It looks like this kind of environmental disaster."

Referring to the frequency of extreme heat wave events, Satterfield noted, "What was once every 20 years, by 2050 will be once every other summer."