As Europe broiled under record-shattering temperatures that are testing the continent’s ability to adapt to extreme weather, Spain on Thursday warned of a possible spike in heat-related deaths.

The continent’s stifling heat wave — the second in two months — has disrupted education, transportation and other aspects of daily life for millions of people, with officials warning that older people or those who work outdoors, like on construction sites, are most vulnerable to the effects of extreme heat.

The heat has also proved deadly.

In Spain, where temperatures soared past 38 degrees Celsius, or 100 Fahrenheit, over several days, official statistical models suggested that more than 200 deaths could ultimately be attributed to the heat wave. The Health Institute of Carlos III, which is linked to Spain’s health ministry, cautioned that the figures were estimates, but officials and experts say there is a clear correlation between extreme temperatures and serious health issues.

In Italy, five people have died from heat exposure this week, according to the country’s main news agency, ANSA. Several of them died while working outside, and a homeless man died in Naples, highlighting the vulnerability of those who had little choice but to be outdoors.

In France, at least 40 people have drowned since the latest heat wave began in the middle of last week, many of them teenagers swimming in unsupervised areas. And French prosecutors said three children were found dead in parked cars this week, in two separate incidents.