It shows skin temperature of the toes before -2 on the figure below and after 0 to 10 min a two-minute dunk in cool water at 59 degrees Fahrenheit, for a group of cold-sensitive subjects black circles and a group of normal control subjects white circles :.
What jumps out at me in this graph is the big difference in toe temperature even before the cold water dip: around 35 degrees Celsius versus 30 degrees Celsius, which corresponds to 95 degrees Fahrenheit and 86 degrees Fahrenheit. Some people have cold feet pretty much all the time! To be fair, this difference is a bit of a self-fulfilling prophecy, because the two groups were selected based on their toe temperatures before immersion and after five minutes of rewarming.
Those whose toes were below 90 degrees Fahrenheit in both cases were classified as cold-sensitive. Out of an initial testing pool of 27 volunteers, nine were identified as cold-sensitive five men and four women , and another nine were chosen as the control group based on their similarities to the cold-sensitive group in age, sex, body shape, and exercise habits. The key question is whether there are any differences between the two groups that might explain why some of them have such cold feet.
One aspect of the study was a series of questions about past recreational cold exposure, focusing on duration, frequency, and severity during the last two years. Based on the responses, the 27 participants were ranked from greatest to least cold exposure.
Next came those who took part in cold-water activities like kite surfing or swimming; then year-around outdoor athletes like runners and cyclists; and finally those who did basically no cold-weather outdoor activities. Are the surfers and open-water swimmers the ones with unusually warm feet, or unusually cold feet? Outdoor acclimatization People who spend a great deal of time outdoors become "outdoor acclimatized. Factors affecting climate acclimatization Your physical condition, age, and other factors also affect how your body copes with heat and cold.
Body fat Lean people tolerate heat better than obese people. Age Elderly persons usually don't tolerate temperature extremes as well as do younger people. Medications Some medications may interfere with the body's ability to tolerate temperature extremes because they affect parts of the brain responsible for temperature regulation.
Metabolic rate A person's metabolic rate—the speed at which the body's cells turn food into energy—affects the person's ability to cope with heat and cold. Prepare to cope with the heat You may be better prepared to cope with the summer heat if the temperature of your indoor environment does not differ radically from the temperature outdoors.
Last reviewed:. October Interested in using our health content? Key takeaway: Cold adaptation produces a number of physiological changes that can assist with weight loss such as changes in resting metabolism and increases in brown fat.
However, like many things, these changes are only effective when accompanied by proper diet and exercise. Similar to exercise in the heat, cold weather produces certain physiological responses that you will need to take into account to maintain proper hydration. For instance, you may have heard that cold weather makes you pee more, which makes you more dehydrated.
This is partly true, according to John Castellani, a research physiologist at the U. Army Research Institute of Environmental Medicine.
Through a process called cold-induced diuresis, cold weather can cause the body to perceive it has too much water available. As skin temperatures drop, blood is shifted to the core. As we point out on our blog , this process mutes the thirst response.
In other words, when you are cold, you are less likely to feel thirsty when you lose fluids. Once you warm up, your brain can process the state of your extremities, and you realize you are very dehydrated.
This process should sound familiar if you have ever spent several hours in the snow feeling fine, only to return indoors and realize you are ravenous and extremely thirsty. You still need to drink water and replenish electrolytes during your winter running.
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