Who says wintertime says dark and cold days. It is therefore difficult to find the motivation for weekly outdoor sports sessions but a study by researchers at Laurentian University in Canada gives a good reason to put on your sneakers and go for a run in the cold. Published in the Journal of Applied Physiology, this suggests that exercise in temperatures close to 0 ° C might burn more fat than normal, at least for high intensity interval training (HIIT). It appears that high-intensity exercise in cold weather triples the oxidation of lipids compared to normal temperatures.
Regular physical activity improves the metabolism of nutrients consumed and helps to regulate lipid (fat) levels in the blood. Previous research has shown that high intensity interval training is better for fat burning as continuous exercise of moderate intensity. In the study, 11 overweight adult volunteers participated in two high intensity exercise sessions separated by a week. In both sessions, they completed 10 one-minute sprints at 90% effort followed by a 90-second recovery period at 30% effort. At the end of the sprint session, volunteers were allowed to calm down by cycling or walking.
More fat burning in the cold
During one session, the ambient temperature was “thermoneutral” at around 21 ° C while for the other session the temperature was 0 ° C. “This is the first study to analyze the effects of cold room temperatures on metabolism during high-intensity interval exercise, as well as on metabolism the next day,” the researchers write in their article. They measured body temperature and participants’ heart rate, the amount of oxygen supplied to the quadriceps muscles during the two sessions. Glucose (blood sugar), oxygen and carbon dioxide levels, as well as gas exchange rates, were also recorded.
After each workout, the volunteers ate a nutrient bar rich in protein and carbohydrates before falling asleep. The next morning, the team offered them a high-fat breakfast, after which blood samples were taken to measure insulin, glucose, and triglyceride levels, to re-determine lipid oxidation rates and to see if the previous night’s benefits had continued. “The study reveals that high-intensity exercise in the cold increased lipid oxidation by 358% during exercise compared to a high-intensity session in a thermoneutral environment, ” added the researchers.
The metabolism does not react differently the next day
However, there was no substantial difference after breakfast the next morning (the postprandial period): metabolic responses longer term after eating this meal, including blood sugar regulation, fat burning, and triglyceride levels, did not change much after working out in the cold. The scientists, therefore, specify that “the addition of a cold stimulus was less favorable for postprandial metabolic responses the next day”. Blood sugar response (change in blood sugar after eating) was even better after exercise in a thermoneutral environment, regarding readings after breakfast.
“The acute benefits are present for a trainingat high intensity intervals in the cold, but the postprandial metabolic responses are less favorable in this specific context ”, underline the researchers. With so few volunteers and only a few HIIT sessions, it’s too early to draw any drastic conclusions, but they feel it’s an interesting starting point to look at. how room temperature can affect fat burning during periods of intensive exercise. They conclude on the fact that it does not matter the physical activity practiced, it is essential for maintaining good health and reducing the risk of chronic disease.