98.6

How does heat kill? It confuses your brain. It shuts down your organs. It overworks your heart

As temperatures and humidity soar outside, what's happening inside the human body can become a life-or-death battle decided by just a few degrees.

The critical danger point outdoors for illness and death from relentless heat is several degrees lower than experts once thought, say researchers who put people in hot boxes to see what happens to them.

Athenians seeking respite from the heat

A bather takes a shower at Alimos beach near Athens, as the temperatures reached 37 degrees Celsius (98.6 degrees Fahrenheit) on Thursday. Greece's Civil Protection Authority has issued weather warnings for the weekend when temperatures are expected to reach 42 degrees Celsius (107.5 degrees Fahrenheit) in central Greece. [Petros Giannakouris/AP]

Mercury to rise further on Thursday

Sweltering conditions in much of the country are to intensify on Thursday with temperatures forecast to reach 37 degrees Celsius (98.6 Fahrenheit) in both Athens and Thessaloniki. Temperatures will dip gradually from Friday, reaching 36C in Athens and 35C in Thessaloniki, and falling to the low 30s next week. [InTime News]

Tourists try to catch a breeze in sweltering Athens

Tourists are seen using Segways on a siteseeing tour of the historic center of Athens on Wednesday, when the latest heat wave took temperatures to a high of 37 degrees Celsius (98.6 Fahrenheit) in the capital. Temperatures are expected to rise further over the coming days, peaking on Saturday when they are forecast to reach 40C (104F) for the second time in a week.