As temperatures continue to drop, runners are trading out their short-sleeves for jackets and gloves. However, like the perils of running in the heat, the winter season brings forth comparable dangers.
Other than the body's natural cold defense mechanisms, including the decrease in energy expenditure, the reduction of blood flow and shivering, winter running brings health threats such as frostbite, hypothermia, dehydration, pulled or strained muscles and broken bones.
Other than wind chill, the most harmful winter condition for runners is ice.
Ice can be hidden underneath snow or can be barely visible on paved streets. Running on ice can result in major falling accidents, broken bones, bruises and even severe head injuries.
Some precautions can be taken to avoid icy conditions including, running at high noon when the sun is high in the sky and putting spikes on the bottom of running shoes.
However, snow can also be a very real threat, too.
"You really have to be aware of the conditions, they can change pretty rapidly," Founder and Head Coach of the Runner Academy Matt Johnson said.
In addition, snow can create a glare. As a result, unlike almost every other time of year, it is important for athletes to wear dark colors, instead of bright, reflective colors, to contrast the snow.
A jogger runs along a snow-covered street in Evanston, Ill., Friday, Jan. 25, 2013.
Nevertheless, the most common mistake winter runners make is wearing too many layers.
During a workout those with multiple layers on begin to sweat, then they get hot and take off those layers. These layers and the skin are damp from sweat and then exposed to the cold air.
"As the body is exposed, you'll become cold and get to the point where it is hard to warm back up. Then you can go into different stages of hypothermia," Johnson said.
These stages include shivering more than normal, confusion, behavior resembling drunkenness, muscular weakness and even hallucinations, according to Founder, Owner and Head Coach at The Running Center LLC in New York City, Mindy Solkin.
Dehydration is also a dangerous consequence for wearing too many layers.
"A lot of times athletes become dehydrated in cold weather because you don't feel the need to be hydrating as often as when its warm," Johnson said.
If dehydration happens, then blood flow is further reduced, blood pressure rises and the body stops sweating.
Colder air also makes it more difficult for the muscles to warm up on their own. Another typical winter running mistake is heading out for a run without first warming up indoors.
"It's important to warm up before you start running," Executive Editor of Runner's World Tish Hamilton said.
Without proper preparations, muscles and tendons in the body can be strained or pulled when immediately worked hard in low temperatures.
To keep running safely in winter conditions, see the tips below from Hamilton, Johnson and Solkin.
2. Avoid cotton and wear layers.
3. Wear mittens over gloves to keep your hands warm.
4. Run into the wind first and then finish with it at your back.
5. Don't be afraid to skip a day or hop on a treadmill if outdoor conditions are not ideal.