How to run in cold weather: layers, warming up indoors, cold air and asthma, ice and the dark, hands and feet, and when the cold needs care

Most cold weather is safe to run in

The ACSM says exercise can be done safely in most cold weather. The danger is being wet, windblown, unseen or on ice: wet clothes about double heat loss, and rain and wind cooled runners on a 10°C day.

Sources 1, 2, 3

Thin layers, and a little cool at the start

A wicking base layer, a warm layer and a windproof or waterproof top, with a hat, gloves and a buff. Change out of damp kit as soon as you stop.

Sources 4, 5

Warm up indoors

A warm muscle works better, by about 2 to 5% per degree. Warm up for 5 to 10 minutes inside so you're warm but not sweaty, then start easy.

Source 6

Cold air won't freeze your lungs

Your airways warm the air to body temperature. In healthy runners, hard running in freezing air narrowed the airways only a little and for a short time.

Sources 7, 8

With asthma or heart disease, take more care

Cold, dry air is a strong asthma trigger: breathe through your nose, cover your mouth and nose, warm up with short bursts and carry your reliever. With heart disease, the cold makes the heart work harder at the same pace, so warm up inside and start slowly.

Sources 9, 10, 11

Ice and the dark

On icy days, choose gritted, lit routes or a treadmill; slip-on grips cut falls on ice in older walkers. After dark, wear reflective strips on your wrists and ankles and a light.

Sources 12, 13

Your body protects its core

In the cold, your body cuts blood flow to the skin, hands and feet to keep your core warm, which is why fingers and toes go numb first. Hypothermia is a body temperature below 35°C, and frostbite can happen when skin is exposed at 0°C or below.

Sources 14, 15, 4

Wet and wind, not just cold

Running makes plenty of heat, so the risk comes when you slow or stop, get wet, or face a strong wind. Heat loss in wet clothes roughly doubles at 5°C, and in 11 men running for an hour at 10°C, rain and wind lowered body temperature and raised energy use. The ACSM advises extra care when wind chill falls below -27°C, which is rare in the UK.

Sources 2, 3, 1

Your airways warm the air

Your nose and airways warm and moisten the air you breathe in to body temperature (37°C) before it reaches the lungs. Breathing hard through your mouth sends colder, drier air deeper, which can narrow the airways for a while. Cold air is a trigger for symptoms rather than a cause of lung disease.

Sources 7, 16

Cool weather suits distance running

Big-city marathon runners were fastest at about 4 to 10°C, but much colder slowed them too.

Source 17

How people differ

Asthma makes cold, dry air a trigger, heart disease raises the heart's workload in the cold, and Raynaud's affects the hands and feet. The NHS lists "people aged 65 and older", people with a long-term health condition and pregnant women among those more vulnerable to cold weather. People with numb feet from diabetes may not feel the cold or a blister.

Sources 18, 11

Thin layers you can adjustStrong evidence

The NHS advises "several loose layers of clothing with a waterproof outer layer", a hat and scarf, gloves or mittens and thick socks in very cold weather. Asthma + Lung UK: "Wear layers of thinner clothing, because a lot of thin layers can keep you warmer than one thick layer". A wicking base layer keeps sweat off your skin; cotton holds it.

Sources 4, 5, 2

Dress to feel slightly cool at the start

Running warms you quickly, so if you're warm standing still you'll be too hot in 10 minutes and soaked in sweat later. Coaching pages suggest dressing as if it were about 11°C (20°F) warmer than it is; we found no study testing that rule, so treat it as a starting point (our editorial suggestion).

Your head isn't specialEmerging evidence

In 8 men in cold water, putting the head under (about 7% of the body's surface) added only about 10% to total heat loss, so the "40% of your heat through your head" claim doesn't hold. Wear a hat because your head is exposed.

Source 19

How cold is too cold?Strong evidence

With the right clothing, exercise is safe in most cold weather; the ACSM advises extra care below a wind chill of -27°C. The International Ski Federation cancels cross-country ski races below -16 to -20°C. In the UK, ice, heavy rain, strong winds and the dark are the more usual reasons to stay in or go shorter.

Sources 1, 20

Change straight after

Damp kit chills you fast once you stop. Change into dry clothes, have a warm drink and warm up gradually indoors.

Source 2

Healthy runners: small, short-lived changesEmerging evidence

In 23 healthy, trained adults doing a hard 4-minute run at -15°C, the main lung function measure (how much air you can blow out in one second) fell 2.7% without a mask and 0.5% with one. In 13 winter athletes at -20°C it fell 4.2% 3 minutes after exercise, and after marathons at -2 to -4°C a measure of the small airways fell while the main measure didn't.

Sources 8, 21, 22

Does cold running damage healthy lungs?Mixed evidence

We found no evidence that ordinary cold-weather running damages healthy lungs, but the evidence is mixed. Long-term airway changes were found in elite cross-country skiers, who breathe over 100 litres a minute for hours in sub-zero air for years: airway biopsies in 40 elite skiers aged 16 to 20 showed inflammation, asthma was more common in competitive skiers (25.9% against 9.2% in a survey with a low response), and it's unknown whether the changes reverse. Yet skiers' cough reflex wasn't left oversensitive, and long-lasting cough was less common than in other people.

No study covers recreational runners, so we can't say for certain either way. Running in ordinary UK winter weather is a long way from hours of elite ski racing at -15°C (our reading).

Sources 23, 24, 25, 26, 7

With asthma, cold, dry air is a strong triggerEmerging evidence

In 13 people with asthma exercising at -25 to -15°C, lung function fell 19% with a dummy mask and 4.3% with a heat-exchanger mask. Dry air may matter more than cold air. Asthma + Lung UK advises breathing in through your nose and loosely wrapping a scarf around your nose and mouth; we found no trial of a scarf.

Sources 9, 7, 5

Warm up with short burstsEmerging evidence

Across 7 randomised studies, warm-ups with short, high-intensity bursts cut the fall in lung function after exercise by about 11 percentage points, while steady, easy warm-ups made no significant difference. Our asthma warm-up follows this pattern.

Sources 10, 20

Masks protect the airways and cost a little speedEmerging evidence

A heat and moisture exchanger mask can warm -10°C air to at least 19°C, but in 23 adults at -15°C it cut the distance covered in a 4-minute time trial by 1.4%. A buff or scarf is the everyday version.

Sources 20, 27, 7

Your reliever and your plan

A US guideline strongly recommends a short-acting reliever before exercise for people with exercise-induced bronchoconstriction (airways that narrow with exercise). Follow your own asthma action plan, as our breathing guide says, and see your GP or asthma nurse if exercise keeps bringing on symptoms.

Source 28

Coronary artery diseaseEmerging evidence

In 16 men with stable coronary disease walking 30 minutes at -15°C against 22°C, the heart's workload was 17% higher in the cold, but there were no signs of the heart muscle going short of blood. In 42 people having heart tests, breathing -15°C air blunted the normal rise in the heart's blood flow during exercise in those with narrowed arteries, and a review found angina comes on sooner during exercise in the cold.

Sources 11, 29, 30

High blood pressureEmerging evidence

In 51 men with untreated high blood pressure and 32 without, 15 minutes at -10°C in wind changed heart rhythm measures in the same way in both groups.

Source 31

Snow shovelling is the bigger strainEmerging evidence

Shovelling heavy snow pushed 10 untrained men to 86 to 97% of their maximum heart rate, and heart attacks in Quebec men rose the day after heavy snow. A run you've built up to, started gently, is a different thing (our reading).

Sources 32, 33

A healthy heart

We found no evidence that running in the cold harms a healthy heart; healthy people in these lab studies coped normally.

Sources 11, 31

With heart disease or angina (our suggestion)

Follow your cardiac team's advice, warm up indoors, cover your mouth and nose, keep the first 10 minutes easy, and move indoors on very cold, windy days. The ACSM says people with heart disease can exercise in the cold but should be monitored closely.

Sources 30, 1

Keep your whole body warm

When your core gets cold, your body cuts the blood flow to your hands and feet. Wear layers and a hat as well as warm gloves and socks, and warm your gloves before you put them on.

Sources 14, 34

Raynaud's and exerciseEmerging evidence

In a Dutch study of 929 women, those with primary Raynaud's were as active as other women, and the NHS advises exercising regularly because it helps circulation. We found no trial of exercising in the cold with Raynaud's. Our Raynaud's guide has the detail: warming up first, layers, and warming up slowly afterwards.

Sources 35, 14

Warm up first, and rewarm slowly

Raise your heart rate and body temperature before you go out, for example by going up and down the stairs, and warm your kit before you put it on.

Sweat cooling on your skin, a cold pool, air-conditioning or the relaxation at the end of a class can bring on an attack. Change out of damp clothes, dry your skin and hair, and warm up slowly: no radiator, fire or very hot shower straight away.

Source 34

Numb feet from diabetes

With numb feet from diabetes, wear well-fitting shoes and check your feet for redness or blisters afterwards; with an open sore or ulcer, don't run until your foot team says so.

Cold numbs feet further, so check them after cold runs (our suggestion).

IceEmerging evidence

In Montreal, nearly half of 960 winter outdoor falls came in three freezing-rain or refreeze spells, and most of those hurt were under 65. A slip-on traction device cut outdoor falls on snow and ice days by more than half in 109 adults over 65, and socks over shoes made icy paths feel less slippery in a small trial. No study was in runners: on icy days, choose gritted routes or a treadmill, shorten your steps and consider grips (our suggestion).

Sources 36, 12, 37

Being seen in the darkEmerging evidence

In the hardest test conditions, drivers recognised only 5% of pedestrians in black clothing, against all of those wearing reflective strips on their moving joints. Reflectors on the wrists and ankles work better than a vest, and people overestimate how visible they are. A Cochrane review found that visibility aids help drivers see people sooner, but no trials of their effect on injuries. The NHS suggests routes with plenty of lighting and reflective clothing.

Sources 13, 38, 39, 40

A warm muscle works betterStrong evidence

In short efforts, performance improves by about 2 to 5% for each 1°C rise in muscle temperature, which is the case for warming up before a cold run.

Source 6

You don't burn much moreEmerging evidence

In 10 lightly dressed men walking or running for an hour at 0°C against 22°C, core temperature didn't change and heart rate was lower. Extra energy comes from shivering, getting wet in the wind, snow and slippery ground. We found no study comparing running in cold and mild air directly.

Sources 41, 2, 3

Hypothermia and frostbite: call 999 or go to A&E

Call 999 or go to A&E (accident and emergency) if, after being in very cold temperatures:

• You have hard, frozen skin, swelling and loss of feeling, or blisters filled with blood or a clear or milky fluid (signs of frostbite).
• You're constantly shivering, with slurred speech, slow breathing, tiredness or confusion (signs of hypothermia). Don't use a hot bath, hot water bottle or heat lamp to warm someone with hypothermia, and don't rub their arms, legs, hands or feet.

Sources 15, 4

Who should take more care

The NHS lists "people aged 65 and older", "people who have a long-term health condition" and "pregnant women" among those more vulnerable to cold weather (our suggestion: start shorter and stay near home on very cold days).

Source 18

On the hill or a long run in the cold

Call 999 or go to A&E (accident and emergency) for hypothermia, such as shivering, pale cold skin, slurred speech, slow breathing, tiredness or confusion, and for frostbite with hard, frozen skin, swelling and loss of feeling, or blisters. Mountain Rescue England and Wales lists the signs to watch for in others: "Disorientation, confusion, shivering, tiredness, pale complexion and loss of circulation in hands or toes", adding that children and older people are especially at risk.

Cold air and asthma

Breathe in through your nose so the air is warmed, loosely wrap a scarf around your nose and mouth or wear a mask, and check the weather: shorten your time outside if it's very cold or windy. In an Asthma + Lung UK survey, 7 in 10 people said cold air made their symptoms worse. Very hot air can tighten the airways too, and GINA advises athletes to avoid training in extreme cold or pollution.

Source 5

With asthma, during exercise

Carry your reliever every time. Stop the session if symptoms don't settle, and call 999 if your breathing doesn't go back to normal after exercise.

In an asthma attack

Sit up straight and try to stay calm. Then:

• With a blue reliever inhaler: take 1 puff every 30 to 60 seconds until you feel better, up to a maximum of 10 puffs. Shake the inhaler between puffs, and use a spacer if you have one.
• With an AIR or MART inhaler (used for both preventing and treating symptoms): take 1 puff every 1 to 3 minutes until you feel better, up to a maximum of 6 puffs.
• If your asthma action plan gives a different maximum dose for an attack, follow your plan.

Source 42

Call 999 for an asthma attack

Call 999 (911 in the US) if you or someone else is having an asthma attack and:

• You start to feel worse at any time.
• You don't feel better after the maximum dose of your reliever.
• You don't have your inhaler.

While you wait, and afterwards

If you're no better after 10 minutes and the ambulance hasn't arrived, use your inhaler again, up to the same maximum dose. If you're still no better and it still hasn't arrived, call 999 again straight away. Don't drive yourself to A&E.

See a GP within 2 days, even if you feel better. Asthma + Lung UK suggests a same-day appointment if you managed the attack yourself. Don't exercise again until your symptoms and breathing have recovered.

See your GP or asthma nurse if

Exercise brings on coughing, wheezing or a tight chest, or you need extra reliever around exercise.

When it isn't asthma

Being unfit or carrying extra weight makes anyone breathless with exercise, and that breathlessness eases quickly when you stop. Inducible laryngeal obstruction (ILO), where the voice box narrows, causes noisy or difficult breathing in, a tight throat or a change in your voice that start and stop suddenly, and your reliever may not help much; it is found in about 3 in 10 people whose asthma is hard to control. Breathlessness with dizziness or tingling points to a breathing pattern problem, and breathlessness on exertion with swollen ankles needs a GP check.

Chest pain that comes on in the cold

Get help from NHS 111: pain or tightness in your chest, neck, shoulders, jaw or arms that comes and goes, often brought on by exercise, stress, emotion or cold and easing after a few minutes' rest. It can be angina, a sign of a heart problem. If you've been diagnosed with angina, get help from NHS 111 too if it feels worse than before, is happening more often, lasts longer or happens when you're resting.

Coronary heart disease is a narrowing of the heart's arteries by a build-up of fatty material. It can cause angina: a pain or tightness, usually in your chest, that is often brought on by exercise, stress, emotion or cold weather and stops with rest or angina medicine. A heart attack happens when the blood flow to your heart is blocked, usually by a blood clot.

Heart disease and the cold (our suggestion)

With heart disease, start indoors on very cold days or warm up inside first and keep the first 10 minutes outside easy, because cold air raises blood pressure and the heart's workload at the same pace.

Source 11

Stop and get medical help

If you get chest pain or pressure, feel faint or dizzy, are unusually breathless, or your heart races or beats irregularly during exercise, as our plans advise.

Call 999 (911 in the US)

For chest pain that comes on suddenly and doesn't go away, feels tight or like squeezing, spreads to your arms, neck, jaw, stomach or back, or comes with sweating, feeling sick, light-headedness or breathlessness; severe difficulty breathing; someone who faints while exercising; palpitations that don't go away, or come with chest pain, shortness of breath or feeling faint; or a headache that starts suddenly and is extremely painful, especially while lifting or straining, or comes with numbness or weakness, difficulty speaking or loss of vision. The NHS says a bleed on the brain may be more likely when lifting something heavy. Don't drive yourself to A&E.

Sources 43, 44, 45

Suddenly more breathless than usual

Call NHS 111 (in the US, your doctor or an urgent care centre) if you're suddenly more short of breath than usual, or have chest pain with feeling sick or a heartbeat that races, skips or flutters.

Numb, white or painful fingers or toes: Raynaud's

See a GP (general practitioner) if Raynaud's is very bad or getting worse, is on one side only, starts after 30, or comes with joint pain, skin rashes or muscle weakness. Get seen as soon as possible for ulcers or black areas on your fingers or toes.

Sources 14, 34

Raynaud's: see a doctor or nurse specialist as soon as possible

Arthritis UK says get seen as soon as possible for:

• Ulcers or black areas on your fingers or toes.
• A colour change in your fingers or toes that doesn't go away as quickly as usual.
• Symptoms, particularly numbness, on one side of your body only.
• Joint pain, skin rashes or muscle weakness.

During a Raynaud's attack

Get out of the cold as soon as you can, but warm up slowly, especially if your fingers or toes have changed colour and hurt. Moving your fingers and toes helps, and tucking your hands into your armpits is the runner's trick. Don't put your hands or feet on a radiator or under hot water.

Chilblains

See a GP if chilblains aren't getting better after 2 to 3 weeks, there's pus coming out, you have a very high temperature or feel hot, cold or shivery, you keep getting them, or you have diabetes.

Source 46

A fall on ice

Call 999 or go to A&E if you heard a crack, the joint or limb has changed shape or points at an odd angle, it's numb or tingling, or the skin looks blue or grey or feels cold. Get help from NHS 111 (in the US, urgent care) if it's very painful, very swollen or bruised, very stiff, or you can't put weight on it or walk more than a few steps.

Call 999 or go to A&E: after an injury, you heard a crack, the foot or ankle has changed shape or points at an odd angle, a bone is sticking out, there is a bad cut over it, you're in severe pain, or the toes look blue or white, feel numb or are cold to touch. These can mean a broken bone. Don't drive yourself.

Same day (NHS 111 or an urgent treatment centre): after an injury, you can't put weight on it or walk more than a few steps, the pain is very bad or getting worse, there is a lot of swelling or bruising or it is getting worse, it feels very stiff, or it's not feeling any better after treating it yourself. Get the same help if you also have a very high temperature, or feel hot, cold or shivery: this could be an infection. If you think it's broken, don't treat it yourself.

Sources 47, 48

Aches and pain

Stiff, achy legs for a day or two are normal at first and ease as you repeat the runs. Stop and rest if a pain is sharp, makes you limp or change how you run, or builds as you go, and skip your next run if it's worse the next morning. The NHS advises not running when you're in pain, and seeing a GP or physiotherapist if it doesn't go away; a very painful or swollen knee, or a sudden sharp pain at the back of the ankle, needs a GP straight away.

Back pain, and pain spreading down a leg

Call 999 or go to A&E: loss of feeling or numbness around the genitals or bottom, new trouble peeing or controlling your bladder or bowels, changes in genital sensation during sex or problems with erections or orgasm, or pain, tingling, weakness or numbness in both legs. These are signs of cauda equina syndrome, which needs treating in hospital urgently. Don't drive yourself.

Pain, tingling or numbness spreading below the knee that isn't settling after a few weeks, is getting worse or stops your normal activities: see a GP.

Numbness, tingling or weakness that travels down the leg from the back. That points to a nerve (sciatica) rather than the knee.

A lump in the groin

A lump in the groin, or groin pain with coughing or straining (a possible hernia).

Get help from NHS 111 if you have a hernia (a lump in the groin or tummy) and pain in or around it, a bloated tummy, you feel sick or are being sick, you're vomiting blood or your vomit looks like coffee grounds, you're constipated, you have a high temperature or feel hot, cold or shivery, or you've suddenly become confused.

Call 999 or go to A&E now if you have a femoral hernia (a small lump at the top of the thigh, in the groin) and very bad tummy pain, you feel sick or are being sick, you cannot fart or poo, you have a high temperature or feel hot, cold or shivery, or you've suddenly become confused. It may be strangulated, which is an emergency. Don't drive yourself.

If you feel faint after a hard effort

Lie down with your legs raised, or sit with your head lowered between your knees, and drink some water. Crossing your legs while standing, rocking up and down on your toes or clenching your fists can help. Call 999 if someone faints while exercising.

Heat exhaustion and heatstroke (warm layers can overheat you too)

In the heat, tiredness, dizziness, a headache, feeling sick, heavy sweating and intense thirst can be heat exhaustion: stop, get somewhere cool, drink and cool your skin, and you should feel better within 30 minutes. If you don't, or there's confusion, hot skin that has stopped sweating, a fit or a collapse, call 999 or 911: that's heatstroke.

Ask for an urgent GP appointment or call NHS 111

Ask for an urgent GP appointment or get help from NHS 111 for a headache that's triggered or made worse by coughing, sneezing, bending down or exercising. In the US, contact your doctor or urgent care.

During any session

Stop straight away if you feel any pain or become unwell, the NHS says, and contact 111 if your symptoms worry you or don't go away.

A dull ache in your muscles for a day or two after something new is normal. Joint pain that's sharp, gets worse during a set or lingers into the next day means switching to the easier option, and seeing a GP or physiotherapist if it carries on (our plans' rule). Our muscle soreness guide has more.

Check first

Speak to a GP first if you haven't exercised for some time, or if you have a medical condition or concerns. Get advice first, too, if you have a health problem, an injury or symptoms, have recently had a heart attack or an operation, or are pregnant or have recently given birth.

Answer the 7 questions of the Physical Activity Readiness Questionnaire (PAR-Q+) before you start. A yes to any (a heart condition or high blood pressure, chest pain, dizziness or fainting, another long-term condition or its medicines, a bone or joint problem, or being told to exercise only under medical supervision) means checking with your doctor or a qualified exercise professional first. It also asks people over 45 who aren't used to hard, all-out effort to check before exercising that hard: think races and time trials, not easy runs. The NHS suggests speaking to a GP first if you're worried about your health.

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A heart condition

If you have a heart condition, follow your cardiac team's advice on how hard to work, and stop for the warning signs above. People with long-term conditions may wish to ask their specialist before starting. With uncontrolled high blood pressure, avoid straining against a held breath; the high blood pressure guide has more.

Not these plans, or not yet

Not these plans, or not yet: myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS), where the National Institute for Health and Care Excellence (NICE) advises against programmes with fixed step-by-step increases and the NHS against vigorous unsupervised exercise such as running; and pregnancy, unless you were already running, because the NHS advises against starting a new vigorous activity such as running.

"Running in the cold freezes your lungs"Strong evidence

Your airways warm and moisten the air to 37°C before it reaches the lungs. We found no study suggesting freezing.

Source 7

"Running in the cold damages your lungs"Mixed evidence

In healthy runners the airway changes were small and brief. Long-term airway inflammation and more asthma were found in elite cross-country skiers training hard for years in sub-zero air, and no study covers recreational runners.

Sources 8, 23, 26

"You lose 40% of your body heat through your head"Emerging evidence

The head is about 7% of the body's surface, and putting it under cold water added only about 10% to total heat loss. Wear a hat because it's exposed, not because it's special.

Source 19

"You burn loads more calories running in the cold"Emerging evidence

Not much more, unless you shiver, get wet or run through snow or on slippery ground.

Sources 41, 2

"Don't run below freezing"Strong evidence

Exercise is safe in most cold weather with the right clothing; the ACSM advises extra care below a wind chill of -27°C.

Source 1

"With Raynaud's, avoid exercising in the cold"Emerging evidence

People with Raynaud's are as active as others, and the NHS advises regular exercise for circulation. Staying warm before, during and after is the key, as our Raynaud's guide says.

Sources 35, 14

"Heart patients should stay indoors all winter"Mixed evidence

The cold raises the heart's workload and can bring on angina sooner, but walking at -15°C caused no signs of heart strain in stable coronary disease, and the ACSM says people with heart disease can exercise in the cold with monitoring. Follow your cardiac team's advice.

Sources 11, 30, 1