Be Weather Wise on Race Day January 4, 2008
Note: The Seton Family of Hospitals is the medical sponsor for the upcoming AT&T Austin Marathon. Between now and February 17, we'll have tips from Seton experts about how runners can become better prepared for the marathon, or any race for that matter. This week, Bob Kunkel, LAT, PT, SCS, Senior Physical Therapist at Seton Northwest Sports Medicine Center explains how we can cope with weather while exercising outside in the elements.
By Bob Kunkel, LAT, PT, SCS, Senior Physical Therapist
Seton Northwest Sports Medicine Center
The Central Texas Area experiences variations in weather and sometimes these changes occur rapidly with little warning. Any individuals who plan to stay outdoors for a period of time, not only those exercising or working outdoors, need to pay attention to three weather indexes: The Wind Chill Effect, the Heat Index Effect and UV radiation. Knowing how the three indexes work, how the temperature and other weather conditions can change at any moment and steps to take to be comfortable in those conditions will make the activities planned for that much more healthy and enjoyable.
Wind Chill Effect
Wind Chill occurs when the temperatures drop and
wind speed increases. (Table 1) Reactions to the wind chill
effect can increase from general discomfort due to the cold, to
moderate shivering, to extreme shivering, pain in the
extremities, muscle cramps, frostbite and hypothermia, as the
weather becomes more extreme.
- The Wind Chill Effect is increased with moisture on the skin & clothing.
- Body heat is lost at a faster rate if there is moisture at skin level.
- Dress appropriately, with a rain barrier and fabrics that wick moisture away from the skin and hold in body heat.
- Wear layers of loose-fitting, lightweight, warm clothing. Trapped air between the layers will insulate you. Outer garments should be tightly woven, water repellent, and hooded.
- Wear a hat, because 40% of your body heat can be lost from your head.
- Cover your mouth to protect your lungs from extreme cold.
- Mittens, snug at the wrist, are better than
gloves.
Our experience has been that the Central Texas weather can have unexpected changes within 12 to 24 hours of the start of the race. It is wise that all runners, volunteers and spectators be prepared for race day. Layer clothing using cold weather fabrics, gloves, head covering and rain gear. All are essential for a safe and comfortable race.
| Temperature (F) | |||||||||||||||||||||||||||||
| Wind (mph) | Calm |
|
35 | 30 | 25 | 20 | 15 | 10 | 5 | 0 | -5 | -10 | -15 | -20 | -25 | -30 | -35 | -40 | -45 | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 5 |
|
31 | 25 | 19 | 13 | 7 | 1 | -5 | -11 | -16 | -22 | -28 | -34 | -40 | -46 | -52 | -57 | -63 | |||||||||||
| 10 |
|
27 | 21 | 15 | 9 | 3 | -4 | -10 | -16 | -22 | -28 | -35 | -41 | -47 | -53 | -59 | -66 | -72 | |||||||||||
| 15 |
|
25 | 19 | 13 | 6 | 0 | -7 | -13 | -19 | -26 | -32 | -39 | -45 | -51 | -58 | -64 | -71 | -77 | |||||||||||
| 20 |
|
24 | 17 | 11 | 4 | -2 | -9 | -15 | -22 | -29 | -35 | -42 | -48 | -55 | -61 | -68 | -74 | -81 | |||||||||||
| 25 |
|
23 | 16 | 9 | 3 | -4 | -11 | -17 | -24 | -31 | -37 | -44 | -51 | -58 | -64 | -71 | -78 | -84 | |||||||||||
| 30 |
|
22 | 15 | 8 | 1 | -5 | -12 | -19 | -26 | -33 | -39 | -46 | -53 | -60 | -67 | -73 | -80 | -87 | |||||||||||
| 35 |
|
21 | 14 | 7 | 0 | -7 | -14 | -21 | -27 | -34 | -41 | -48 | -55 | -62 | -69 | -76 | -82 | -89 | |||||||||||
| 40 |
|
20 | 13 | 6 | -1 | -8 | -15 | -22 | -29 | -36 | -43 | -50 | -57 | -64 | -71 | -78 | -84 | -91 | |||||||||||
| 45 |
|
19 | 12 | 5 | -2 | -9 | -16 | -23 | -30 | -37 | -44 | -51 | -58 | -65 | -72 | -79 | -86 | -93 | |||||||||||
| 50 |
|
19 | 12 | 4 | -3 | -10 | -17 | -24 | -31 | -38 | -45 | -52 | -60 | -67 | -74 | -81 | -88 | -95 | |||||||||||
| 55 |
|
18 | 11 | 4 | -3 | -11 | -18 | -25 | -32 | -39 | -46 | -54 | -61 | -68 | -75 | -82 | -89 | -97 | |||||||||||
| 60 |
|
17 | 10 | 3 | -4 | -11 | -19 | -26 | -33 | -40 | -48 | -55 | -62 | -69 | -76 | -84 | -91 | -98 | |||||||||||
Heat Index
Why are we discussing a heat index in January? It is not unheard of for race day to have temperatures in the 70s and approaching 80 degrees in the early afternoon. This is usually not a problem for runners who train in southern climates and are acclimatized to these conditions. However, those who train in colder climates or do the majority of their training on a treadmill may not have adopted to the warm and humid environments.
Start time temperatures can be in the 50s or 60s with a high relative humidity. (Table 2) We have even experienced showers with warm temperatures on race morning. With a humid atmosphere and the heat effect from the sun, runners can see an increase of sweating, muscle cramping and an increase in body temperatures. We frequently see runners in the marathon medical tent in a state of dehydration and muscle cramping when these conditions occur.
Be Prepared
- Wear clothing for heat situations that help with cooling the body. Light color and light weight.
- Be smart about the pace you run at. Decreasing the
amount of work your body is doing can help your body
produce a little less heat.
- Take advantage of water stops along the race course.
- For longer distances be sure to replace electrolytes.
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UV Index
Ultraviolet radiation is associated with skin damage. Race day is no different than any other day. UV Radiation hits its peak during mid day and obviously is more on sunny days, with little or no cloud cover. (Table 3) Prolonged exposure to UV radiation is associated with cataracts and melanomas. Wear sun glasses to protect your eyes and use clothing and sun screen to protect your skin.
As described in other sections of the UV information, the UV Index is a forecast of the probable intensity of skin damaging ultraviolet radiation reaching the surface during the solar noon hour (11:30-12:30 local standard time or 12:30-13:30 local daylight time). The greater the UV Index is the greater the amount of skin damaging UV radiation. How much UV radiation is needed to actually damage one's skin is dependant on several factors. But in general the darker one's skin is, (that is the more melanin one has in is/her skin) the longer (or the more UV radiation) it takes to cause erythema (skin reddening). For those who always burn and never tan the times to burn are relatively short compared to those who almost always tan.
The EPA has devised general guidelines as far as what to do to protect oneself from overexposure to UV radiation. These are shown in the table below.
Minimal
| Exposure Category | UV Index | Protective Actions |
| 0, 1, 2 | Apply skin protection factor (SPF) 15 sun screen. | |
| Low | 3, 4 | SPF 15 & protective clothing (hat) |
| Moderate | 5, 6 | SPF 15, protective clothing, and UV-A&B sun glasses. |
| High | 7, 8, 9 | SPF 15, protective clothing, sun glasses and make attempts to avoid the sun between 10am to 4pm. |
| Very High | 10 | SPF 15, protective clothing, sun glasses and avoid being in the sun between 10am to 4pm. |
Graphic information used courtesy National Oceanic and Atmospheric Administration's - National Weather Service
Seton Family of Hospitals and GoodHealth.com wish you a safe and enjoyable race day!
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