How Cold Is Too Cold When Running

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Winter can be tough for runners. It’s hard to get up in the morning and head out for a run, it gets dark early, and then there’s wind, snow, and ice.

And yet, we runners are determined. The cold won’t stop us!

But… How cold is too cold when running? How do you know when it’s ok to go for a run and when you should stay inside?

Here’s our guide to figuring out whether running in the cold is safe. Having run in New York for over twenty years, we have personal experience navigating cold weather in all sorts of conditions.

How Cold Is Too Cold for a Run?

There’s no specific temperature that’s “too cold” for everyone. It comes down to how cold-tolerant you are.

We have friends who run in shorts unless it’s below 20 degrees. But we also have other friends who stick to the gym when the temperature drops below 50 degrees. So it can really vary from person to person.

That being said, it’s generally accepted that sub-zero temperatures (Fahrenheit) can be dangerous.

The American College of Sports Medicine suggests staying indoors if the wind chill falls below -18 degrees Fahrenheit. This is the range at which frostbite occurs most easily, so you’ll be at risk if you’re outdoors.

However, you can still run in these conditions if you’re well-prepared. This means the right clothes, gear, and mental fortitude.

But it’s important to note that runners with conditions such as asthma, cardiovascular disease, diabetes, and Raynaud’s syndrome may struggle more in cold weather.

How Your Body Responds to the Cold on a Run

The cold slows down the body’s processes as blood moves closer to your core to try and raise the temperature near your organs. That means your arm and leg muscles might be sluggish because they’re not receiving the same blood as usual.

This also affects energy expenditure. Your body will likely fatigue faster in the cold, so you’ll need to fuel sooner.

As the blood vessels constrict and keep the blood closer to the core, your extremities may start to feel numb and tingly. This process also causes a reduction in the hormone that indicates thirst, so you can easily dehydrate without realizing it.

You may also experience a runny nose, a sore throat, and burning lungs.

Does Cold Affect Performance and Perceived Effort?

Keeping up your usual pace and effort is more difficult when there’s less blood in your extremities—especially your legs.

Your perceived effort will increase, but your actual performance will likely decrease. This may change as your body adjusts to cold weather.

Things to Consider Before Running Outside In Cold Weather

If you’re planning on running in cold weather any time soon, consider these factors before you head out, so you can stay safe.

Temperature

Check the temperature. If there’s a temperature you don’t feel comfortable with, it might be an indoor exercise day. However, remember that wind affects how warm or cold it feels. A cold, windless day might be better to run in than a milder, windy day.

Wind Chill

Wind chill is the real killer in cold weather. It’s advisable to stay indoors on very windy and cold days.

Lower than a wind chill factor of -18 degrees Fahrenheit is indoor weather. You can calculate wind chill using this handy calculator.

Precipitation

Snow, rain, and sleet can be dangerous. They make the surfaces slippery and can also chill you to the bone if you aren’t wearing the right gear. These conditions may also impact visibility.

Personal Tolerance

If you hate being outdoors in the cold, it’s probably not a good idea to run outdoors in the cold! Your personal tolerance does matter, and there’s no need to push yourself through it if you can arrange a treadmill or something similar.

Type of Run or Training Intensity

If you plan on doing speedwork, you’ll need to warm up for longer to ensure your muscles are ready. Higher-intensity exercise will warm you up faster, but the chance of injury is high if your muscles aren’t ready for it.

On the other hand, if you want to take a long, easy run, you can get away with less warming up, but it will still require a few miles before you feel comfortable.

We find it usually takes 20-30 minutes before being fully warmed up during winter runs. This varies by runner but however long it normally takes you to warm up, expect it to take longer on cold runs.

Your Fitness Level

The fitter you are, the more easily you should be able to handle the cold. This isn’t true for everyone—your personal preferences will also come into play—but generally, a fitter person can handle the cold better.

This could be because the fitter you are, your cardiovascular system strengthens. As your heart pumps harder and faster, it circulates blood through the body more easily, helping your muscles to perform better.

Benefits of Running in the Cold

Yes, there are benefits to running in cold weather! Here’s what you can expect if you run consistently in cold weather.

Improved Endurance

If you run in the cold often, your body will soon adapt and start gaining strength to handle the cold better. Your cardiovascular system will improve as it works harder against the cold to keep you surviving and performing.

It may not feel like it at the time, but when you eventually get back to running in warmer weather, you’ll be surprised to find that your endurance has improved.

Enhanced Mental Resilience

If you can stay disciplined enough to get up and run in the cold, you’ll develop a surprising amount of mental toughness.

Similar to the benefits of an ice bath, you can become a lot more mentally tough just by exercising in cold weather.

Increased Immunity

The more your body gets used to the cold, the stronger your immune system gets. You should find you can handle small sniffles more easily without it developing into something worse, and your health will improve over time.

Boosted Mood and Increased Energy

The restored blood flow once you get back into the warmth can give you an energy rush. And nothing feels as great as coming in from a good run, so your mood will be up!

Risks Associated with Running in Cold Weather

Although there are benefits to running in the cold, there are a few potential dangers as well. Keep these things in mind.

Hypothermia

Hypothermia is an abnormal and life-threatening drop in body temperature. Once a person reaches this point, their body’s usual temperature-regulation properties stop working, so they can’t warm themselves up again.

If you aren’t dressed correctly, and you run into sleet, heavy rain, or a high wind chill, your body may be unable to handle it.

Frostbite

Frostbite is a reality because when the blood is drawn to the core, it leaves less blood flow in the extremities. This is why fingers, toes, and ears are more susceptible to frostbite—they’re also often exposed.

Irritated Lungs

The cold air can irritate your lungs. Usually, the mouth and throat warm the air before it reaches the lungs. But in cold weather, your body can’t do that, which means that cold air is hitting the lungs directly and could cause irritation and pain.

Slips and Falls

There’s more chance of slipping in icy, windy, and wet weather. And when you’re cold, and your muscles are stiff, a fall can have worse consequences. Wearing the wrong shoes can also increase the risk!

Tips for Running in Cold Weather

Running in cold weather is an experience… But it doesn’t have to be a bad one! Here are the best tips for running safely and effectively in cold weather.

Assess the Conditions

Assess the weather to make sure it’s still safe to run in. If it’s just a bit of rain, you might be okay to run in it. But if there’s dangerous ice, harsh winds, or conditions that could risk your safety, it might be best to opt for the treadmill or find another exercise for the day.

Choose the Right Footwear

Breathable running shoes are amazing in hot weather. But they can become icy vessels of discomfort and pain in cold weather. Cold wind blowing into your shoes can chill or numb your feet, so it’s in your best interest to choose less breathable footwear for cold weather running.

There are numerous ways to keep your feet warm on winter runs, but first prize is to choose a pair of shoes that doesn’t let the wind in.

Depending on the conditions where you run, you might also need waterproof shoes, you might need to use ice cleats, or you may want to try trail running gaiters to protect yourself from deep snow.

Pre-Run Warm-Up Routines

Warming up is always important. But it’s even more important in the cold because it gets the blood flowing and helps the muscles warm up before you put them through exercise.

Warm-up slowly, with a brisk walk and some gentle stretches. Don’t overdo it. It’s a good idea to do some dynamic stretching indoors to get a head start on warming up before you head outside.

Plan Your Route Carefully

If you know the area well, avoid any spots that might get icy, and wet, or that could trap winds, like narrow corridors or alleys.

Plan your route to be as safe as possible in the freezing weather. It’s also a good idea to stick to a public route in case something happens so that you can get help.

Slow Down and Adjust Your Stride

Maintaining the same pace as you can hold in warm weather might be difficult. Don’t let this frustrate you—you may need to drop your pace and adjust your stride in the cold so that you don’t lose your form as you stiffen up in the cool air.

Keep Your Focus on the Path Ahead

Focus on the path ahead to spot and avoid any possible hazards, like puddles, ice, or unplowed areas of snow. Be especially careful if you run on sidewalks – the owner often clears these, and the surface and condition will vary from property to property.

If you fall in the cold, you’re more likely to be injured, so it’s important to be aware of your surroundings.

Dress Appropriately

Layering is your best friend in the cold. Choose warm, close-to-the-skin base layers, light top layers, and a light jacket, preferably one that packs down so you can remove it if necessary. A beanie, neck gaiter, or balaclava can protect your ears and throat from the cold.

Hydration and Fueling Considerations

Don’t forget to hydrate during your run. If it’s not hot, it can be easy to forget that your body needs hydration, so it might help to set reminders on your watch to drink. Also, you may need to fuel yourself sooner in the cold, so take an energy bar or chew.

Listen to Your Body

If you’re struggling to run in the cold, pay attention to your body and how it responds. Pain and numbness should be assessed carefully and if the pain doesn’t go away with rest, you may need to get it checked.

If pain is a common occurrence when you run in the cold, you may need to make some changes. You might need to warm up for longer, or try warming up inside where you’re not in the cold air. As a last resort, you may need to consider investing in a treadmill, where you can control the temperature in the environment.

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AUTHOR

Ben is an avid road and trail runner, and has completed multiple marathons and ultras. A former running store owner, he now shares his knowledge and experience writing these articles.