An exercise scientist says you need a 20-minute warm-up in the cold—is that overkill or smart training?

I never fail to warm up before strength training, but I always skip that step on the rare occasions I go for a run. At best, I manage a couple of token hip openers and lunges, but I know I should spend more time preparing my body.

Even so, I was taken aback when I read the recommendation to warm up for 20 minutes when exercising outdoors in the cold. That’s according to Athelie Redwood-Brown, a senior lecturer in performance analysis of sport at Nottingham Trent University, in the UK.

Could this possibly be true? I prayed that it wasn’t, but contacted Redwood-Brown to find out more.

“People often underestimate how much longer the body takes to prepare in winter compared to summer,” Redwood-Brown tells Fit&Well.

“In colder outdoor conditions, it takes longer for muscles, tendons and joints to reach a temperature where they are more elastic and able to tolerate load.

“Cold muscles are stiffer and less responsive, which increases injury risk. Around 20 minutes allows core temperature to rise gradually, improves blood flow to working muscles, and prepares the nervous system for faster, more forceful movements.

“When muscles are warmer, they can produce force more efficiently and are less likely to strain. If you’re not sufficiently warmed up, tissues are stiffer and less able to absorb load, increasing the likelihood of muscle strains or tendon injuries.”

How cold does it need to be to spend more time on the warm-up?

“From a physiological point of view, cold becomes meaningfully relevant once ambient temperature drops to around 5°C (41°F), and especially below freezing,” says Redwood-Brown.

Here’s a cheat sheet from Redwood-Brown.

• Below 32°F/0°C: Allow ~20 minutes of progressive warm-up
• Around 35°F/2°C: 12-15 minutes
• Around 41°F/5°C: 8-10 minutes
• Above 50°F/10°C: A standard warm-up duration is usually sufficient

How to warm-up

“This should include light aerobic movement followed by progressive dynamic exercises,” says Redwood-Brown.

“Dynamic movements actively take joints through ranges of motion while muscles are contracting. This helps elevate muscle and core temperature, improves coordination and prepares the body for the specific demands of the activity.

“Anything shorter than this significantly reduces the protective effect of a warm-up, especially in cold or windy conditions.”

Redwood-Brown says dynamic stretches are better than static ones for a warm-up.

Redwood-Brown also says to save the static stretches—where you hold a stretch—for the cool down. “Static stretching involves holding a muscle at end range [the limit of your joint’s movement] for a prolonged period. While useful for flexibility and recovery, doing it before exercise can temporarily reduce your performance by impacting muscle force and power output.

“Dynamic stretching, by contrast, helps you move better. I’d save static stretching for after exercise when muscle tissues are warm and the goal is recovery rather than performance.”

Do you need to warm-up for low-intensity exercise?

The answer is still yes, but the warm-up doesn’t have to be as specific or as intense.

“In cold environments, muscles, tendons and joints are stiffer regardless of intensity,” says Redwood-Brown. “A longer warm-up is still advisable even for low-intensity exercise, but it doesn’t need to be aggressive or fatiguing.

“For low-intensity activity in the cold, the extended warm-up should focus on things like gradually raising core temperature, increasing joint range of motion and light dynamic movements, such as brisk walking, mobility or easy drills.

“For high-intensity exercise, the longer warm-up becomes essential, as cold tissue is more injury-prone and power output is reduced until tissues are properly primed.

“The colder it is, the longer your warm-up should be, regardless of intensity, but the harder the session, the more critical that extra warm-up time becomes.”