WINTER RUNNING
Winter running: build your base through cold, rain and ice
We think winter is the season to build your base: mostly easy running, week after week. Cold and wet make hard running harder, so warm up close to your start time and stay warm until you set off. Plan for ice, because falls on ice and snow send many people to emergency departments, and on a bad day a treadmill set to a 1 percent incline comes closest to the energy cost of running outside.
Why winter is for your base
Your base is the easy running underneath everything else: many runs at an effort where you could still talk in full sentences, week after week. We think winter is the season to build it. That is our view, not a finding from the studies on this page.
Winter suits it. The studies below suggest cold and rain make hard running harder, and an easy run is a session you can still do on a cold, dark evening, outside on a cleared path or on a treadmill.
What cold and wet do to your running
A 2015 review[1] says the few studies on the topic suggest that aerobic performance is degraded in cold environments, and that strength and power fall as muscle temperature drops. The authors also say the effect of cold on performance has not been thoroughly studied, so read it as a direction for your own pace.
Rain adds to the cold. In a lab study of 12 healthy young men[2], each man ran on a treadmill for an hour at 80 percent of his maximal oxygen uptake, a hard effort, in 5 degrees Celsius (41 degrees Fahrenheit) air, once with simulated rain and once without. With rain, body temperatures were lower, and later in the hour oxygen use, rating of effort and blood lactate were higher. The study says little about an easy jog.
Air temperature also shows up in race results. In an analysis of six large marathons[3], higher air temperatures went with slower finish times for the median finisher and the top 10 men in almost every race, a link, not proof. The authors describe 10 to 12 degrees Celsius (50 to 54 degrees Fahrenheit) as the optimal range. Its abstract reports only the link with warmer air and gives no result for race days colder than that range.
- 1. Castellani and Tipton, Comprehensive Physiology, 2015: cold stress effects on exposure tolerance and exercise performance checked 19 Oct 2026
- 2. Ito et al., Journal of Sports Medicine and Physical Fitness, 2019: rain exacerbates cold and metabolic strain during high-intensity running checked 19 Oct 2026
- 3. Llewellyn and Maceri, Journal of Sports Sciences, 2025: air temperature and marathon finishing time in elite and average runners checked 19 Oct 2026
Warm-up, thirst and cold injury
Warm-up timing matters more in the cold. In a study of 5 rowers and 5 runners[4], each athlete did a 15-minute warm-up, waited 5 or 30 minutes, then did a time trial in 24 degrees Celsius (75 degrees Fahrenheit) or 5 degrees Celsius air. The biggest drop in time-trial performance came after the 30-minute wait in the cold. The authors suggest timing the warm-up close to the start and keeping skin and core temperature up with clothing.
Thirst may also fade. In two small lab experiments with 8 and 9 men[5], thirst was lower during moderate exercise in 4 degrees Celsius (39 degrees Fahrenheit) air than in 27 degrees Celsius (81 degrees Fahrenheit) air, whether the men were well hydrated or short of fluid. A cold run may leave you less thirsty than a mild one, even when you need a drink.
Cold injury has its own guidance. A 2021 consensus statement from the American College of Sports Medicine[6] covers the nature, prevention and treatment of the most common cold injuries, and notes that cold injury can result from exercising at low temperatures. This page does not summarize its advice. For very low temperatures, read the statement itself.
- 4. Spitz et al., Journal of Strength and Conditioning Research, 2014: elapsed time after warm-up and performance in a cold environment checked 19 Oct 2026
- 5. Kenefick et al., Medicine & Science in Sports & Exercise, 2004: thirst sensations at rest and during exercise in the cold checked 19 Oct 2026
- 6. Castellani et al., Current Sports Medicine Reports, 2021: ACSM expert consensus statement on injury prevention and exercise performance during cold-weather exercise checked 19 Oct 2026
Snow, ice and the treadmill
Falls on ice and snow follow the weather. A study of 16 Finnish cities over 14 winters[7] compared weather with slip injuries on walking commutes. Slips were more common with snow on the ground, and near-zero temperatures with precipitation were typical on days with more slip injuries. A study of 14,977 emergency visits for falls on ice or snow in Calgary over 11 years[8] found that ice on the day, snow on the ground and ice in the previous three days went with more visits. Neither study counts runners, and both show a link, not proof.
No study here counts runners’ falls, so the next lines are general advice and not from a study. Choose cleared paths over untouched snow, shorten your stride on slick ground and think about traction devices for your shoes when ice is likely. Wear reflective clothing and carry a light when you run in the dark.
A treadmill is the other option. A belt has no air resistance, so it costs less energy than the road at the same speed. In nine trained male runners who ran at six speeds from about 10.5 to 18 kilometers per hour (6.5 to 11 miles per hour)[9], a treadmill incline of 1 percent came closest to the energy cost of running outdoors on a level road.
- 7. Hippi and Kangas, International Journal of Environmental Research and Public Health, 2022: impact of weather on pedestrians’ slip risk checked 19 Oct 2026
- 8. Tarcea et al., Canadian Journal of Public Health, 2024: the Slip and Fall Index, assessing the risk of slipping and falling on ice checked 19 Oct 2026
- 9. Jones and Doust, Journal of Sports Sciences, 1996: a 1% treadmill grade most accurately reflects the energetic cost of outdoor running checked 19 Oct 2026
An easy run in Complete’s library: Easy Run (Recovery)
This is the run we would repeat across a winter: Easy Run (Recovery), from Complete’s library. It starts at a walk, settles into a relaxed, conversational run and ends with a stretch. Effort runs from 1 (very easy) to 10 (all out), and the main run sits at 3. No study on this page tests an easy run in the cold.
It is a general easy run, and you can do it outside on a cleared path or on a treadmill. On a treadmill, the 1 percent incline above applies. World’s Greatest Stretch is a lunge with a twist that opens the hips and upper back.
| Block | What | Prescription |
|---|---|---|
| Warm-up | Run | 180 seconds (3 minutes) at effort 2. Start at a walk and drift into a jog. |
| Main | Run | 1,800 seconds (30 minutes) at effort 3. Relaxed and conversational. If you’re tempted to push, you’re going too hard. |
| Cool-down | World’s Greatest Stretch | 1 set of 4 reps on each side. Open the hips while the body is warm. |
| Easier | A shorter run | Run 15 to 20 minutes, or swap for an easy spin on any machine you have if the legs are flat. |
| Harder | A longer run | Extend to 40 minutes, but keep the effort easy: this is not a hidden workout. |
Where Complete fits
Complete starts from your long-term goals, not a plan; the goals steer the recommendation for each day. Every workout that reaches Apple Health counts toward your score and the recommendation for each day, in any sport. Running workouts move the running Roads, which are Complete’s ladders of targets.
Complete sets your zones from your own heart data. Your recovery score comes from HRV, resting heart rate, sleep and breathing rate against your own baseline. When it’s red, today’s session turns into rest or an easy session. A plan comes in when you have a race: running (5K to ultra), Hyrox, or general fitness.
The Easy Run session above is in Complete’s own training library, and you can run it yourself and log it in the app. Workouts are logged in the app exercise by exercise, with the distance of each run and the weight and reps of each lift. Over time Complete gets to know your body, your schedule and the sports you play. Complete is free to download, and logging and sharing your workouts on it stay free.
If a study or a number here is wrong or out of date, email support@ccomplete.app and we’ll correct it.
Frequently asked questions
What should I train in winter?
We think winter is for building your base: mostly easy running, week after week, outside or on a treadmill. That is our view, not a study finding. The library run on this page is one easy session you can repeat through the winter.
How cold is too cold to run outside?
No study cited here sets a temperature cutoff. Studies of walkers link ice and snow to more slips and emergency visits, and the 2021 consensus statement from the American College of Sports Medicine covers cold injury at low temperatures. As general advice, and not from a study, move indoors when the path is icy or the air is colder than you can dress for.
Does cold weather slow you down?
It can. A 2015 review says the few studies on the topic suggest aerobic performance is degraded in the cold and that strength and power fall as muscle temperature drops. A lab study found that rain made hard running at 5 degrees Celsius harder. The evidence is thin and gives no number for an easy run, so treat it as a direction.
How should I warm up for a winter run?
Warm up close to your start time and keep warm after. In a study of 5 rowers and 5 runners, a 30-minute wait after the warm-up in 5 degrees Celsius air cut time-trial performance the most, and the authors suggest clothing to keep skin and core temperature up. The library run on this page starts at a walk and drifts into a jog over 3 minutes.
Is it safe to run on ice and snow?
Studies of walkers link snow on the ground and ice to more slips and emergency visits, and no study cited here counts runners’ falls. General advice, not from a study: choose cleared paths, shorten your stride, think about traction devices and move indoors when the surface is icy. If you have a health condition or an injury, ask a doctor before you change how you run.
Is a treadmill run the same as running outside?
In energy cost, a treadmill at a 1 percent incline comes close. In nine trained male runners, that incline came closest to the cost of outdoor running on a level road, because a belt has no air resistance. The study measured energy cost only, so surface, weather and footing still differ between the two.
Do I need to drink on a cold run?
Thirst may not tell you. In two small lab experiments with 8 and 9 men, thirst was lower during moderate exercise in 4 degrees Celsius air than in 27 degrees Celsius air, whether the men were well hydrated or short of fluid. That finding is not a drinking rule, and this page gives no amount. For how much to drink, ask a doctor or a dietitian.
What should I wear for a winter run?
No study cited here tests running clothes. The research points to two things: keep skin and core temperature up after a warm-up, and know that rain made the body colder in a lab test. General advice, not from a study: dress in layers you can take off, cover your hands and head, and add something reflective for the dark.
Does a winter run count in Complete?
If your watch or phone saves the run to Apple Health as a workout, it counts toward your score and the recommendation for each day, as every workout that reaches Apple Health does, in any sport. Running workouts move the running Roads. Complete is free to download, and logging and sharing your workouts on it stay free.