Running in the Cold: Performance, Warm-Ups and What Actually Needs Protecting

Winter running has a reputation problem. The first steps out of the door on a frosty morning feel stiff and slow, and it's easy to conclude that cold weather is bad for performance and something to be endured until spring. For many triathletes, the off-season is also when running volume goes up, so how you handle cold runs matters for several months of training.

The evidence points the other way on performance. Cool conditions are where distance runners tend to run fastest, and the problems the cold causes are mostly about the first few minutes, exposed skin, wind and wet. This article covers what race data and lab studies show about temperature and endurance, why cold muscles feel slow, what a warm-up does in winter, and which parts of you actually need protecting.

What cold does to a runner

Running produces a lot of heat. Even at an easy pace, your muscles generate far more heat than your body needs to stay warm, and in summer the main challenge is getting rid of it. That's why TriForward's "The Watts the Heat Takes" and "Humid, Not Just Hot" deal with heat as a performance limiter.

In the cold, the balance changes. Your body has an easier job shedding heat, which is good for performance, but two things can go wrong:

• Before you're warm, your muscles and skin are cool, and cool muscles don't contract as quickly or forcefully.
• If you lose heat faster than you make it, because of wind, rain, wet clothing or a slow pace, your core and extremities can cool. That's where comfort, performance and safety start to suffer.

For a healthy runner moving at a steady pace, the second problem is uncommon in a typical UK or northern European winter. It becomes more likely on long runs, when you slow down or stop, in wind and rain, and at the end of a long session when you're tired.

What race data say about temperature

The strongest evidence on temperature and running performance comes from analyses of large numbers of race results. These are observational, so they can't separate temperature from everything else that varies between race days, but they do include huge numbers of runners.

North American marathons

A 2007 study by Ely and colleagues in Medicine & Science in Sports & Exercise analysed results from seven North American marathons, including Boston (36 years of data), New York (29 years) and the Twin Cities (24 years). They looked at the top three men and women and the runners in 25th, 50th, 100th and 300th place, and compared their times with course records. Weather was measured as wet-bulb globe temperature (WBGT), which combines air temperature, humidity and radiant heat, and race days were grouped into four bands from 5 to 25 °C.

• Men were 1.7% slower than course records in the coolest band (WBGT 5 to 10 °C), 2.5% in the next, 3.3% in the third and 4.5% in the warmest band (20 to 25 °C). These differences were statistically significant.
• Women showed a similar pattern, from 3.2% in the coolest band to 5.4% in the warmest, though the differences weren't statistically significant.
• Slower runners were more affected by rising temperatures than faster ones.

The authors concluded that marathon performance slows progressively as WBGT rises from 5 to 25 °C. Note what this study didn't do: it didn't look at conditions colder than 5 °C WBGT. It shows that cool is better than warm, not where the optimum sits or what happens below freezing.

Nearly 1.8 million marathon performances

A 2012 study by El Helou and colleagues in PLoS ONE went larger. It analysed 1,791,972 performances from six major marathons (Berlin, Boston, Chicago, London, New York and Paris) between 2001 and 2010, across 60 races.

• The optimal temperature for the fastest mean speed varied with performance level, from about 3.8 to 9.9 °C.
• Above those optima, running speed fell and withdrawal rates rose. The Chicago Marathon in 2007, run at 25 °C, had the highest withdrawal rate of the 60 races, at 30.74%.

That puts the best conditions for marathon running cooler than many triathletes would expect: around the temperature of a typical British winter morning.

Elite races across six disciplines

A 2022 study by Mantzios and colleagues in Medicine & Science in Sports & Exercise looked at elite racing more broadly. It analysed 1,258 races and 7,867 athletes between 1936 and 2019 in 42 countries, across the marathon, 50 km and 20 km racewalking, 10,000 m, 5,000 m and 3,000 m steeplechase. Race-day WBGT ranged from −7 to 33 °C, and 27% of races were in cold or cool conditions.

• The optimal range was a WBGT of 7.5 to 15 °C, equivalent to about 10 to 17.5 °C air temperature.
• Outside that range, performance fell by about 0.3 to 0.4% for every degree of WBGT.
• Air temperature was the most important weather factor in the models.

Because the decline was measured on both sides of the optimal band, this study suggests that very cold conditions can also cost performance, not just heat. Inference: for a runner aiming at a 50-minute 10 km, 0.3 to 0.4% is roughly 9 to 12 seconds per degree of WBGT outside the band. That's an estimate from elite data, not a measured effect in age-group runners.

What the race data can't tell you

All three studies are about racing, mostly in well-trained or elite runners, and none studied triathletes. They also capture a whole race day, not the separate effects of cold air, wind, rain or clothing. They're good evidence that cool conditions suit endurance running, and much weaker evidence on exactly where the cold starts to hurt.

A lab study: when cold was best

Lab studies can control temperature precisely. The classic example is a 1997 study by Galloway and Maughan in Medicine & Science in Sports & Exercise, though it used cycling, not running.

8 healthy men cycled to exhaustion at about 70% of their maximal oxygen uptake at four temperatures: 3.6, 10.5, 20.6 and 30.5 °C, with the same humidity and a light airflow.

• They lasted longest at 10.5 °C, an average of 93.5 minutes.
• They lasted the shortest time at 30.5 °C, an average of 51.6 minutes.
• Temperature significantly affected time to exhaustion, heart rate, skin and core temperature and other measures.

This was a tiny, all-male sample in a lab with little airflow, and time to exhaustion at a fixed intensity isn't the same as a race. But it fits the race data: moderately cool conditions are where endurance performance tends to be best.

Why the first kilometres feel slow

If the cold is good for endurance, why does a winter run feel so heavy at the start? The answer is muscle temperature.

A 2010 review by Racinais and Oksa in the Scandinavian Journal of Medicine & Science in Sports summarised research on temperature and neuromuscular function. For short-duration efforts, performance improves by about 2 to 5% for every 1 °C rise in muscle temperature. The reverse also applies: cooler muscles produce less force and power, and nerve signals travel more slowly. The review linked performance impairments in both cold and hot conditions to changes in neural drive, the signal from the nervous system to the muscle.

A 2015 review by Castellani and Tipton in Comprehensive Physiology reached a similar view. Strength and power fall during cold exposure, mainly because muscle temperature drops. They also noted that aerobic performance in the cold hasn't been thoroughly studied, and only a few studies suggest it is degraded, possibly through lower body and muscle temperatures, cardiovascular changes and altered metabolism.

Inference: most of that sluggish early feeling is cold muscles and stiffness rather than a real loss of fitness. Running warms your legs quickly, so the feeling usually fades once you've been going for 10 to 15 minutes. The time it takes will vary with the temperature, the wind and what you're wearing, and no study has measured it in triathletes.

Warm-ups in the cold

A warm-up raises muscle temperature and gets your heart, breathing and nervous system ready for harder work. A 2010 meta-analysis by Fradkin and colleagues in the Journal of Strength and Conditioning Research included 32 high-quality studies and found that warming up improved performance in 79% of the criteria examined. None of these studies was specific to the cold, and most tested short, intense tasks rather than endurance runs.

In winter, the warm-up itself doesn't need to change much. What changes is how quickly you lose the heat you've built. Inference from the muscle-temperature research above:

• For easy runs, the first 10 to 15 minutes at an easy pace are the warm-up. There's no need to do more.
• For intervals and tempo runs, an easy 15 to 20 minutes plus a few short strides before the main set makes sense, as it would in summer. Keep a layer on through the warm-up and only take it off just before the first effort.
• Keep recoveries moving. Standing still between reps in wind or rain lets your legs cool again. Jog or walk the recoveries, and keep them short.
• Before a winter race, finish your warm-up as close to the start as you can, and keep a jacket or old top on until the last moment.

TriForward's "Should You Stretch Before You Run?" covers whether static stretching belongs in a warm-up. Cold weather doesn't change that evidence.

What actually needs protecting

For most runners in a typical winter, the risks are local rather than whole-body. The American College of Sports Medicine's 2006 position stand on preventing cold injuries during exercise, by Castellani and colleagues, starts from the point that exercise can be done safely in most cold-weather environments. Its recommendations focus on knowing the warning signs and managing the conditions.

Hands, ears and face

Fingers, ears, nose and cheeks lose heat quickly because they're small, exposed and far from the body's core. The position stand recommends using the wind-chill temperature index to estimate frostbite risk, with heightened surveillance below a wind chill of −27 °C. That's rare in the UK, but wind chill can be well below the air temperature on an exposed hill or seafront.

• Gloves or mittens keep fingers working and comfortable, and they're light enough to tuck away once you warm up.
• A hat or headband protects the ears.
• In strong, cold wind, a buff or face covering helps.

Wet and wind

Wet clothing and wind take heat away much faster than still, dry air. A long run in cold rain, especially if you slow down or stop, is a bigger risk than a dry run at a lower temperature. Inference: plan long winter runs so you can get home or indoors quickly if you get soaked, and carry a light windproof layer.

The end of a long session

You produce most heat when you're running steadily. On a long run, at the end of a brick session or when you stop for a fuel break, heat production falls. If you're wet with sweat, you can cool quickly. This is when shivering and real discomfort tend to start.

People with heart or lung conditions

The position stand recommends closer monitoring of people with conditions such as asthma or cardiovascular disease in the cold. Cold air can trigger airway narrowing in people with asthma or exercise-induced bronchoconstriction. TriForward's "Winter Wheeze" covers this in detail.

Dressing for the run you're doing

No trial has tested winter running clothing in triathletes, so this section is practical inference from the heat-balance principles above:

• Dress for the middle of the run, not the doorstep. If you're warm when you set off, you'll probably be too hot after 15 minutes. Feeling slightly cool for the first few minutes is normal.
• Use layers that you can unzip or remove, rather than one very warm top.
• Avoid cotton next to the skin. Fabric that stays wet keeps cooling you.
• Adjust for the session. An easy, slow run needs more clothing than a hard interval session at the same temperature, because you produce less heat.
• Start into the wind on an out-and-back route if you can, so that you're running with the wind on the way home when you're sweaty and tired.

Populations and evidence quality

The evidence base is lopsided:

• Race data are large but observational, mostly from well-trained or elite marathon runners, with men far better represented than women. In the Ely study, the pattern in women was similar to men's but not statistically significant.
• Lab studies of temperature and endurance are tiny and mostly in young men. The Galloway and Maughan study had 8 men, and it used cycling.
• Muscle-temperature research is mostly about short, powerful efforts, not long runs.
• No studies have looked at triathletes running in the cold, or at running after a cold bike ride.

Castellani and Tipton noted that cold tolerance varies with habituation, body size, sex and fitness. That suggests individual responses differ a lot, and your own experience is a better guide than any population average.

A triathlon scenario

The following example is illustrative, not drawn from a study. A 38-year-old triathlete is building run volume through the winter for a half-distance race in June. Her Sunday long run is 90 minutes, and on a January morning it's 2 °C with a strong wind and rain forecast later.

An evidence-informed approach might look like this:

• Timing: she runs before the rain arrives, rather than in the afternoon.
• Route: she starts into the wind and loops past home at 45 minutes, so she can change a wet top or cut the run short.
• Clothing: a long-sleeved base layer, a light windproof jacket, gloves and a headband. She feels a little cool for the first ten minutes, then unzips the jacket.
• Pacing: she expects the first two or three kilometres to feel slow and doesn't chase pace until she's warm.
• After: she changes out of wet clothes straight away rather than stretching outside.

On a Wednesday interval session, she warms up for 15 minutes in a jacket, keeps it on until the first rep, and jogs the recoveries rather than standing still.

For a brick session, she starts the run with a dry top and gloves ready in transition. Inference: running in sweat-damp cycling kit on a cold day is when a short brick run can turn uncomfortable, especially if the bike was indoors and she steps outside into cold air.

Common mistakes

• Overdressing. Starting warm usually means overheating and sweating heavily, then cooling quickly later.
• Judging fitness on the first kilometre. Cold muscles are slow. Wait until you're warm before checking pace.
• Standing still between intervals in wind or rain, then starting the next rep with cold legs.
• Ignoring wind and rain. The thermometer alone underestimates how cold a run will feel.
• Hard efforts on icy or dark paths. The fall risk is often bigger than any cold-related risk.
• Skipping gloves because the rest of you feels warm. Hands and ears often get cold first.
• Pushing through chest symptoms on cold days, assuming it's just the cold air. That needs medical advice.

What we don't know

• Where the cold starts to cost performance. Race data show that cool beats warm, and one large study shows a decline below the optimal range, but there's little evidence on very cold conditions or on age-group runners.
• Women's responses. Race datasets include women, but most lab studies of temperature and endurance don't.
• Triathlon-specific effects. No study has tested running in the cold after cycling, or a cold-weather transition.
• How long the warm-up needs to be. There's no cold-specific warm-up research in endurance runners.
• Clothing choices. Advice on layers and fabrics is based on heat-balance principles rather than trials in runners.

References

• Ely MR, Cheuvront SN, Roberts WO, Montain SJ. Impact of weather on marathon-running performance. Medicine & Science in Sports & Exercise, 2007;39(3):487–493. doi:10.1249/mss.0b013e31802d3aba
• El Helou N, Tafflet M, Berthelot G, Tolaïni J, Marc A, Guillaume M, Hausswirth C, Toussaint JF. Impact of environmental parameters on marathon running performance. PLoS ONE, 2012;7(5):e37407. doi:10.1371/journal.pone.0037407
• Mantzios K, Ioannou LG, Panagiotaki Z, Ziaka S, Périard JD, Racinais S, Nybo L, Flouris AD. Effects of weather parameters on endurance running performance: discipline-specific analysis of 1258 races. Medicine & Science in Sports & Exercise, 2022;54(1):153–161. doi:10.1249/MSS.0000000000002769
• Galloway SDR, Maughan RJ. Effects of ambient temperature on the capacity to perform prolonged cycle exercise in man. Medicine & Science in Sports & Exercise, 1997;29(9):1240–1249. doi:10.1097/00005768-199709000-00018
• Racinais S, Oksa J. Temperature and neuromuscular function. Scandinavian Journal of Medicine & Science in Sports, 2010;20(Suppl 3):1–18. doi:10.1111/j.1600-0838.2010.01204.x
• Castellani JW, Tipton MJ. Cold stress effects on exposure tolerance and exercise performance. Comprehensive Physiology, 2015;6(1):443–469. doi:10.1002/cphy.c140081
• Castellani JW, Young AJ, Ducharme MB, Giesbrecht GG, Glickman E, Sallis RE. American College of Sports Medicine position stand: prevention of cold injuries during exercise. Medicine & Science in Sports & Exercise, 2006;38(11):2012–2029. doi:10.1249/01.mss.0000241641.75101.64
• Fradkin AJ, Zazryn TR, Smoliga JM. Effects of warming-up on physical performance: a systematic review with meta-analysis. Journal of Strength and Conditioning Research, 2010;24(1):140–148. doi:10.1519/JSC.0b013e3181c643a0