The study was approved by the ethics committee of Northern Ostrobothnia Hospital District (statement number 240/2010) and all participants were informed of the study and were requested for informed consent. They had also the possibility to terminate the study at any point. The data collected during the study is maintained unavailable from other than project personnel and protected with passwords. Data-analyses are performed without any personal identification (name, address etc.). The research applied a short cold exposure with well protected subjects and did not, therefore, cause any pain or harm to the participants.