Everybody knows that exercise is essential to keep us healthy. It lowers the risk of heart disease, and helps us to maintain a healthy weight. It also reduces stress and makes us happier. Doctors say that exercising in cold weather is even better for us. Going for a jog or even a swim when it's chilly or freezing outside has extra benefits for our physical and mental health. The reason for this is that the cold gives our heart a more energetic workout. Dr Angela Pepdjonovic, from the Hospital for Special Surgery in New York, explained why. She said: "Your heart has to work a little bit harder to pump blood around your body…in the cold. This can help to boost your endurance over time."

Dr Pepdjonovic said cold-weather workouts can help the body burn calories at a faster rate. She said: "As your body is required to work harder to maintain its core temperature, you actually increase your calorie burn by exercising in the cold." Physical activity in cold temperatures can boost our metabolism, which helps us lose weight. In the cold, our metabolism slows down, so we can preserve fat and keep warm. Another benefit is that being in natural light helps to reduce our stress. This is especially so for people who suffer from Seasonal Affective Disorder (S.A.D.). This is a type of depression caused by the shorter, darker days of winter. It is more common in people who live far from the equator.