When we react to a changing environment, conditions inside our bodies change. Your body’s main instinct is survival, so it reacts to potentially dangerous situations.
When you exercise, most of the energy in your body is released as heat energy and your temperature rises. To lower your body temperature, blood moves to the surface of your skin where it can cool down. Water also evaporates from your skin as sweat, helping to cool your body. During the winter months, physical changes can also help an animal to hibernate, whilst food is scarce.
In the winter months, some animals, like dormice, are no longer able to find food. Their bodies are able to adapt, and they “hibernate”. The animal “sleeps” for the winter. Its body gradually gets colder, its heartbeat slows down and it breathes less often. In this condition animals use little energy. They can survive without eating and live off stores of fat inside their body.
In the fall, many birds migrate to a warmer winter climate.
It is important to drink after exercise to replace fluid lost through perspiration.