Berlin: The collapse of Germany winger Karim Bellarabi during a pre-season match this week has forced Bundesliga clubs to rethink their training schedules due to the heatwave currently gripping northern European.
The 28-year-old broke down during a friendly 2-0 win for Bayer Leverkusen at fourth-division minnows Wuppertal on Tuesday.
He was later diagnosed as having suffered a circulatory collapse, due to temperatures well over 30 degrees Celsius.
Bellarabi, who last played for Germany in 2016, was released from hospital in Wuppertal, near Duesseldorf, on Wednesday and is expected to return to training in the coming days.
Leverkusen said the winger "suffered excessive physical strain due to extreme heat".
Leverkusen coach Heiko Herrlich suspects Bellarabi simply did not drink enough water during the match, "but the heat was extreme, it was brutal on the body even for those not playing".
The German weather service in Potsdam, near Berlin, is forecasting the hot weather here to continue well into next month.
With the Bundesliga set to resume on August 24, some clubs are rethinking their training schedules or moving sessions indoors.
Leverkusen have switched Friday's planned outside afternoon training session to 0930 local time (0730 GMT).
Likewise on Thursday, Schalke, who are 90 kilometres (56mi) away in Gelsenkirchen, brought their training slot forward to 1000 in an attempt to avoid the heat.
"Bellarabi may not have been fully fit," Prof. Dr. med. Wilhelm Bloch from the German Sport University in Cologne told SID, an AFP subsidiary.
"During exercise, you can lose several litres of fluid within a short space of time.
"Three to five litres within one hour is quite possible."
However, it is not just players who swelter during matches.
RB Leipzig, who host Swedish team BK Hacken on Thursday, will sell fans bottles of water at a reduced rate of a euro ($1.17) for their Europa League, second qualifying round, first-leg, which kicks off at 1830 (1630 GMT).