Dr. Kevin Most: Heat and safety
Well, it appears that summer has finally hit, heat indexes hitting over 100 last week. Now if you have watched the news over the past few weeks you have heard of the heat in the southwest, temperatures over 120 degrees have shut down airports and put people at risk, we always hear about the dry heat in the west and how dangerous it can be. This is a time as we go out and enjoy the summer activities we are aware of what to look for and how to prepare safely.
The body is pretty amazing, it has a goal of keeping the body at a temperature that allows all parts of the body to function properly. Think of the range of temperature your body can function in, from 30 below zero to well In the winter we try to make sure that we maintain our body temperature from the extreme cold. We discuss the moves that people can make to prevent frostbite during the winter and now during the summer we discuss what we need to do to prevent heat related illness and injuries.
So when the temperature warms our body makes changes to keep us cool. We all think of sweating as something the body does as we work out or with heavy activity. How many times have you heard someone say “I worked up a good sweat today” Although it is a reaction to activity, the reason for sweating is to keep our body cool. The sweat actually acts as a cooling agent as air blows over it and speeds its evaporation. So essentially the air blowing over the sweat allows us to dissipate heat from our body and helps keep our core temperature in a functional zone. The concept of sweat is great and very functional, the problem we run into is when the humidity is high, the ability for the sweat to evaporate is hindered and thus not as effective as a cooling mechanism. A relative humidity of over 60% slows or hampers the ideal body cooling, now I am not sure if we are ever at a relative humidity below 60 from May thru October. For example the relative humidity over the past week has been in the 90 % range, so sweat at that time does not evaporate and aid in cooling.
The combination of temperature and relative humidity allow us to calculate the heat index. This is the “feels like” temperature. We get concerned when that heat index approaches 100 degrees. For example an air temp of 90 degrees with a relative humidity of 60% equates to a heat index of 100, these are levels that concern us. So when planning an outdoor activity please look at the heat index expected for that activity.
So we have a wide spectrum of heat related illnesses and it is important to know the difference between the inconvenience and the life threatening conditions.
Heat Exhaustion is a condition we find after exposure to high temperature, this occurs more quickly with individuals who are dehydrated. Individuals who are suffering from heat exhaustion often are suffering from a combination of dehydration as well as electrolyte depletion. These individuals will show signs of thirst, weakness, headache, nausea, vomiting and muscle cramps. These patients may also have profuse sweating. Each of these signs a hint that dehydration is causing this more than excessive retention of body heat.
The treatment of this condition can often be treated at home or in the field. The goal is to cool the patient as well as replenish the fluids in the individual. Getting the patient into an air condition facility is best however treatment can also be done outside. Cooling techniques include removing tight or unnecessary clothing, place cool wet towels or ice towels on the skin and encourage intake of fluids. You want to refrain from alcohol or caffeine based drinks. Ideally water and Gatorade or sports drink is best.
Just like we have discussed with frostbite the treatment immediately following is important, patients who have experienced heat exhaustion will be more prone to heat exhaustion for the next week. It is important to be careful with any activity the following week. Individuals at risk include all who are working outside, individuals who take diuretics for blood pressure, young kids and infants and seniors are at the highest risk.
Before we touch on the more dangerous heat stroke, let’s talk more about what you can do to minimize your chances of any heat related illnesses. First is be aware of the heat index for any activity you have planned that will not be in an environment where a cooling option is not close. Make sure you have access to fluids, taking 8 -12 ounces immediately before the activity and then continually thru the day, drinking 8-12 ounces every 30 minutes is key to fluid balance. I am an advocate of alternating water with sports drinks. Sports drinks help replenish some electrolytes as well as provide some glucose.
Wearing light loose fitting clothing is also important, this allows for air circulation as well as not acting as an insulation layer. Remember this is the opposite of what we do in the winter as a tight fitting polyester base layer helps us retain heat.
As far as type of clothing, loose breathable fabrics are great as well as polyester that repels sweat. Try to arrange for frequent breaks from the activity. (cut the grass in sections, rest after 9 holes) also consider changing your active periods to early in the morning or in the evening when the temperature has dropped.
So let’s now talk about heat stroke, this is a life threatening emergency and must be identified and treated quickly. In these individuals the bodies cooling system has shut down and the core body temperature continues to rise. This can cause major organ damage, brain damage and death. For any patient you think heat stroke may be a possibility, call 911 and start the cooling process while waiting for the paramedics. These patients may be unable to take fluids and in those cases do not force fluids, do the other measures to lower the body temperature. Water on the skin, remove excess clothing, fan or forced air blowing over the skin, ice packs in the axilla and groin may be used but refrain from them in seniors and young children.
So what does a heat stroke patient look like, this is an individual with a temp that may approach 104 degrees. Often they are confused, agitated and have slurred speech. Do not assume this is due to alcohol intake. These individuals often have dry hot skin as the sweating mechanism has shut down. These individuals have flushed skin, rapid breathing and heart rate that is often well over 100. The key to identifying these patients is the change in skin color, no sweating and the mental status changes. These are the individuals that will need emergent lifesaving medical treatment.
Patients who are at risk for heat stroke include those individuals who are older and live in a home that does not have air conditioning. In the city we see neighborhoods where seniors are afraid to go out of the home and also keep the windows shut. These are the individuals that need well checks when the heat index approaches 100. We also need to be concerned with children under the age of four and those over the age of 65 as these two groups adjust to heat less efficiently as children and adults. Individuals who take antihistamines for allergies, diuretics for blood pressure and beta blockers for heart conditions are also at risk.
So again what can we do to prevent heat related illnesses
1. Try to arrange for activity at cooler times of the day
2. Look for shady areas to use
3. Drink extra fluids to prevent dehydration, drink fluids before you exercise and then continue to take in fluids
4. Alternate water with sports drinks to replenish electrolytes and glucose
5. Make arrangements to always have fluids with you
6. Wear light colored and loose fitting clothes and a hat
7. Use sunscreen SPF 30 or more
8. Avoid fluids that are alcohol or contain caffeine. Both cause dehydration
9. Check on Seniors, especially if they have no cooling in the home
10. Seniors know there are cooling stations in the city, look for senior centers or local libraries for some relief
11. Never leave anyone in a parked car, temps can rise quickly and dramatically in parked cars.
12. Be careful, exercise close to home, keep a buddy with you