When it is warm and humid outside most people dream of being able to cool off by diving into a pool of cold water. This can provide rapid relief but the exact opposite can be equally refreshing.
"Many people have no idea that the kick you can get from taking a sauna bath in summer is even greater than during the winter months," said Hans-Juergen Gensow of the German Sauna Federation based in the town of Bielefeld.
"In the summer months, visitors to the sauna tend to make more use of the facilities outside and they are more likely to take long, cold showers than they would do in the wintertime", said Gensow. This enhances the feeling of cooling off, making sauna users feel even more rejuvenated when they leave.
"As it is warmer outdoors the coolness of the air outside the sauna or the water under the shower does not come as so such a shock," said Hertel.
Despite these positive indications doctors do warn against excessive perspiration in the summer months.
"Pregnant women, elderly people, those with serious heart complaints and patients with circulatory problems should be cautious," said Wolf von Roemer, head of Germany's professional association of internal medicine specialists in Munich. "In such cases the extra heat of the sauna could aggravate an existing condition."
In order to get the most out of a summertime stay in the sauna, those who feel fit enough should observe a few simple rules.
"The main thing is not to overdo it," said von Roemer. A session should not last more than between 10 and 20 minutes. "Intervals between sauna sessions should last for at least 20 minutes, otherwise too much fluid will be lost from the body", said the expert. A drink of cool liquid afterwards is both refreshing and relaxing but it is best to stick to mineral water or diluted fruit juices rather than down a beer or other alcoholic drink.
Despite the temptation to do so, those who exit the sauna should not head straight for the cold shower or baths.
"Let the body become adjusted to the fresh air and take on the oxygen it needs", said Hertel. After cooling off, summer sauna users are advised to take warm footbaths.
"A lot of people, particularly beginners, skip this part of the procedure but it helps the body to discharge excess warmth and prevents unpleasant bouts of sweating long after a person has left the sauna," said Hertel.
"Those planning a holiday in a particularly hot region can also use the sauna to become acclimatised to the higher temperatures," said Hertel.
This opinion is not shared however by von Roemer who claims that people accustomed to temperatures of under 35 degrees centigrade simply cannot physically prepare themselves for even hotter climes. He does believe though that those who regularly take a sauna tend to be less sensitive overall to extremes of heat and cold.