Temperatures are set to soar in the US around the July 4 holiday, a week after Europe struck new records. With experts predicting more intense and more frequent heat waves in the future, can our bodies adapt?Late June brought record-breaking temperatures to France, Spain, the United Kingdom, Belgium, the Netherlands, Switzerland and Germany. The national weather service, DWD, reported that Germany had never experienced such intense heat for such a long stretch so early in the year. Now, large parts of the central and eastern United States are also living under heat warnings heading into the July 4 holiday weekend, with extreme heat expected to push temperatures as high as 100 to 115 degrees Fahrenheit (37.8-46.1 C) across much of the region. A heat wave like this, with daytime temperatures well above 30 degrees Celsius (86 Fahrenheit) and nights when the thermometer doesn't drop below 20 C, places enormous strain on the human body. That is especially true for young children, pregnant women, older adults, people with underlying health conditions and those who perform physically demanding work or work outdoors. Are people from hotter regions better able to cope with heat? "The human body can adapt, and those adaptations are more developed in people who are continuously exposed to heat," said Claudia Traidl-Hoffmann, a physician and university professor. She is director of the Institute of Environmental Medicine at the University of Augsburg, where she treats patients with environmentally related illnesses. Traidl-Hoffmann is also director of the Institute of Environmental Medicine at Helmholtz Munich, where she researches environmental diseases. As a member of the German government's scientific advisory council, she advises policymakers. Adaptation to changing environmental conditions takes time, Traidl-Hoffmann writes in her book "Medicine of the Future — Healing in a Changing World" (original German title: "Die Medizin der Zukunft — Heilen in einer veränderten Welt"). But it's not a matter of years — rather, it will take centuries. What happens to the human body in the heat? "Once outdoor temperatures reach 23 C (73.4 F), the body begins activating mechanisms to regulate its temperature," Traidl-Hoffmann explained. Blood vessels widen, allowing the body to release heat. Sweating provides additional cooling. Together, these processes help keep the body's core temperature stable. If these mechanisms don't work properly or fail altogether, the consequences can range from cardiovascular disease and stroke to multiple organ failure. The latter happens when the body can no longer maintain a stable core temperature. "When our body temperature rises too much, metabolic processes initially accelerate further — until the body loses control — across all levels from the immune system to the nervous system. At around 42 degrees Celsius (107.6 F), the body experiences severe cell damage, multiple organ failure and, without immediate treatment, death can occur," said Traidl-Hoffmann. The lungs also suffer in extreme heat. At the molecular level, the underlying processes are not yet fully understood, Traidl-Hoffmann said, but there are several hypotheses. Breathing in hot air appears to accelerate inflammatory processes. "The lungs become inflamed more easily and more vulnerable to infections," she said. What should we do — and avoid — during a heat wave? Traidl-Hoffmann said people tend to think about heat and its effects only after temperatures have already soared — when railroad tracks begin to buckle, roads crack and emergency services are stretched to their limits. She advises her patients to prepare for hot weather as early as January. That includes discussing possible medication adjustments with their doctor. Because heat can accelerate inflammatory processes, conditions such as allergies should be treated in advance with specific immunotherapy whenever appropriate. Heat can also worsen eczema, making early treatment important. "Every chronic condition should be stable before the heat season begins," the physician said. Once the thermometer starts to climb, Traidl-Hoffmann recommends drinking plenty of water, eating light plant-based meals and avoiding cigarettes and alcohol whenever possible. Getting enough sleep also gives the body a chance to recover from at least some of the day's heat stress. Can our bodies adapt to a warming climate? Heat keeps many people from getting enough sleep, and the body is more likely to reach what doctors call decompensation, the point when it can no longer compensate for physiological dysfunction. How well the body can cope with heat and adapt to it all depends on how vulnerable a person is. Traidl-Hoffmann compares the body's capacity to adapt to a barrel: For older people, those with chronic illnesses or those taking medication, the barrel fills up much more quickly during a heat wave. Young, physically fit people who are accustomed to hot weather generally have a greater tolerance, she said. But still, this also has its limits. "This exponential increase in the number of hot days, this rapid pace of change, is beyond what ecosystems and humans can adapt to," she said. This article was originally written in German.