DR. LISBETH HOYT PT, DPT & CSCS.
Winter running season is upon us, and whether you love it or hate it, it’s here to stay for a little while longer. As you may have already noticed, running in cold weather presents many challenges! Extreme temperature changes, hot and cold alike, add extra stress to your cardiovascular system. Unlike summer running, it’s vital in winter to keep your chest (and heart) warm while running.
While everyone has a different threshold of what they consider cold, temperatures at just 50 degrees Fahrenheit have been shown to impair endurance capacity. A recent study looked at how temperature affected the physiological responses of 9 soccer players during submaximal and maximal cycling exercise (I know, it’s not the same as running, but the results still apply). Participants cycled in 3 different temperatures for 20 minutes at 60% of VO2max, then intensity was increased until exhaustion. Data was collected on physiological responses such as oxygen uptake (VO2), heart rate, minute ventilation, blood lactate and time to exhaustion.
The three temperature conditions were 10 + 1, 22 +1 and 35 +1 C (respectively 50, 71 and 95 degrees F) which is considerably warmer than what we New Yorkers consider winter. However, the results showed that VO2, heart rate, ventilation, and blood lactate were all impaired during rest, submaximal, and maximal exercise in 10 and 35 degrees C. Additionally time to exhaustion was shorter in these conditions.
Cold temperatures cause your blood vessels and arteries to get smaller which restricts blood flow and oxygen to and from the heart. This forces your heart to work harder, which increases your blood pressure and heart rate. Before you even start your run, your heart rate becomes elevated while working to warm your body up. This makes it even more important to do a quick warm-up when heading out for a winter run. On really cold days, add an extra layer that specifically covers your chest (a vest or tank works well) under your long sleeve. By keeping your chest warm, your body can direct blood flow (and warmth) to your arms and legs, warming your muscles up faster and supporting you through your run.
Don’t forget that it will feel about 10-20 degrees warmer outside to you once you get going. I’m a notoriously overdressed runner, so it’s important for me to remember to wear easily shed-able layers. It is still possible to overheat in freezing temps!
*Source: No, M., & Kwak, H.-B. (2016). Effects of environmental temperature on physiological responses during submaximal and maximal exercises in soccer players. Integrative Medicine Research, 5(3), 216–222. doi: 10.1016/j.imr.2016.06.002