Environment, individual characteristics, clothing will affect the occurrence of hypothermia.
People will be movement and work in cold weather (such as low temperature, strong winds, cloudy and rain / water). In most cases, the cold weather is not the exercise of conduct disorder.
Many factors (including environmental, clothing, body composition, health status, working status, age and exercise intensity, etc.) interact to determine in a cold environment with a warm environment the same physiologic motion if there are more strains or sports injuries Danger.
However, in some cases (such as immersion, rain, wind low ambient temperature), the entire body and local thermal equilibrium in motion - can not be maintained cold stress, leading to hypothermia, frostbite, reduced exercise capacity and performance.
Sports - cold stress can increase the risk of morbidity and mortality in high-risk populations, such as patients with ischemic heart disease and asthma crowd. Cold air intake so that the crowd can also aggravate disease. When the heat exceeds the heat generating hypothermia occurs, the lead body to reduce body heat.
1. medical problems: frostbite
When the tissue temperature dropped to 0 ℃, frostbite occurs. Most prone to frostbite exposed skin site (e.g., nose, ears, cheeks, exposed wrist), hands, feet.
To touch with bare skin can cause frostbite cold objects, particularly highly conductive metal or stone, they can quickly heat. Feng cold temperature index table is the air temperature and wind speed combined with the ability to assess the refrigeration environment.
WCT particularity that the correct application, and for walking speed 1.3m / s outer skin of the individual risk of frostbite exposure assessment. The following are considerations include wind and WCT important information about:
The picture shows the wind chill temperature index refers to the correlation between the time of exposure to the facial skin frostbite Fahrenheit. Wind chill index from the National Weather Service, frostbite time from the Canadian Meteorological Society / Environment Canada
● air does not make the exposed object becomes colder than the ambient temperature.
● wind speed obtained from the weather reports do not bring the wind into account human factors (such as running, skiing).
● WCT shows correlation exposed facial skin frostbite and frostbite time (FIG) expected to occur between. The reason for choosing facial skin because the body is typical of this part of the unprotected area.
● damp skin exposed to the wind, the temperature drops quickly. If the skin is wet and exposed to the wind, the WCT table should be applied 10 ℃ lower temperature than the actual ambient temperature,
● When the ambient temperature is below -15 ℃, the risk of frostbite> 5%, but WCT talked -27 ℃ or less should increase surveillance measures to ensure the safety of the sport. Under the above conditions, the skin can be exposed to frostbite within 30 minutes.
2. Notes clothing
Winter clothes is reduced by the action of heat insulation from air interlayer between the two layers of cloth and clothing to protect against hypothermia and frostbite. Typical winter clothes include three layers:
(1) an inner layer (such as a thin polyester or polypropylene fibers);
(2) an intermediate layer (such as sheep wool or wool), plays a role in the inner insulation;
(3) an outer, breathable role in blocking wind and rain.
Recommendations on the clothing worn should include the following:
● Adjust the heat-insulating layer of clothing to minimize sweating.
● use vents apparel reduce the accumulation of sweat.
● Unless there is rain or wind, generally do not wear clothes of the outer layer.
● When the exercise intensity increases, the heat insulating layer to reduce the garment.
● Do not use a single standard clothing in a whole sports team.
3. Exercise Prescription
During aerobic exercise, the temperature of the whole body and face induce reduction of angina. Movement - the type and intensity of cold stress can alter the risk of heart disease in patients with the disease, including the movement of the upper body or increase their metabolic function will increase the risk.
Snowplow can increase heart rate 97% HRmax, systolic blood pressure (SBP) was increased to 200 mmHg /
● evident in crowded or soft snow walking can increase demand for energy and myocardial oxygen demand, so patients with atherosclerotic heart disease had slowed walking speed.
● patients with heart disease is a threat in swimming in the water less than 25 ℃ (77 ℉), because they do not recognize the symptoms of angina, and thus make ourselves into great danger.
Tip: The content of this article is for reference only, please refer to the consultation results of regular hospitals!