Everyone is in danger, even those in good health. Danger is greater for elderly people, people suffering from chronicle diseases or from mental health troubles, people who regularly take medicine and people who are isolated. Watch for dehydration and heatstroke, especially in sportsmen and people working outside. Pay attention to children. Heatstroke symptoms are : a fever above 40°C, hot, red and dry skin, headaches, nausea, drowsiness, intense thirst, confusion, convulsions and loss of consciousness.