Cold Temperature Control
The weather has turned to fall overnight. Temperatures are dropping. Getting used to the colder temperature is always a challenge for everyone. It can be a real challenge to those with spinal cord injury. An area of the brain, the hypothalamus, is the control center for temperature. However, there are also some spontaneous controls for body temperature within the body.
When the body senses cold, it will react automatically through the Autonomic Nervous System (ANS). The hair follicles in the skin, and the outer skin will detect a chill. Messages will be sent to the brain to start to regulate the body for a drop in temperature. This includes constriction of the blood vessels to pack your circulation tighter, which will keep you warmer. Metabolism increases, generating a bit of internal heat. If your skin senses the chill, your body will shiver to create heat internally. Shivering is powered more by skin control than brain control. All of this occurs without your thinking about it because the ANS will take over. Eventually, your brain will tell you to get a sweater, blanket, or to find some heat.
When the body senses heat from warmer weather or fever, it will respond in the opposite way. The ANS will dilate blood. This allows the circulation to help to cool your body. A small amount of fluid is released from the skin in the form of sweat. Sweating is controlled more by skin perception of heat than by brain control. The moisture on the skin cools the body.
After spinal cord injury, automatic regulation of temperature is disrupted at the level of the spinal cord injury. You may sense a temperature change in or on your body above the level of injury. Your body below the level of injury will sense the temperature change as well. A message will be sent to your brain, but it will only travel as far as your level of injury. None of the body’s responses to circulation will happen below the level of injury because the brain does not realize that part of your body is cold or warm.
After spinal cord injury, the ANS is disturbed and less able to create responses or responses that are quick enough to adjust. Normally, individuals with injury at T6 or above have more difficulty, but recent research shows that the level of injury that affects the ANS can be quite lower.
A malfunction in messages sent from the body’s sensors of increased cold or heat is stopped just below the level of spinal cord injury. The messages are still being sent but cannot pass through the level of spinal cord injury. At the same time, the brain, particularly in the hypothalamus, cannot send messages to the body to make the internal physical changes to adjust to temperature change. These messages are sent but are stopped just above the level of spinal cord injury.
Those with complete injuries have the most impact on temperature regulation. Those with incomplete injuries have variable internal abilities to control the temperature because some messages are getting through the injury site. Nerves that are affected and which are not are different for every individual with incomplete spinal cord injury.
After spinal cord injury, shivering can happen only above the level of injury. Adjustments in circulation and metabolism cannot be made below the level of injury. The body responses of shivering or sweating are typically absent from the body below the level of injury.
When this happens, your core body temperature can drop or rise. Getting your body warm after a drop in core temperature is a challenge for everyone with spinal cord injury. Cooling the body when too warm is equally difficult. Temperature regulation becomes more of a challenge with the higher of injury.
Everyone has a slightly different body temperature. The average is 98.6°F, but that is only an average. Most individuals with spinal cord injury will have a slightly lower temperature. When your internal body temperature drops, hypothermia is diagnosed. This means your body temperature is below the normal temperature for you. When your internal body temperature becomes too high or overheated, hyperthermia is the condition.
Maintaining your body temperature can be accomplished in four different ways.
Modification of the environment You might not be able to control the temperature regulating processes inside your body, but you can control the world outside of your body. Being prepared for cold or heat is one of the best defenses against becoming too cold or too hot.
Make sure to dress appropriately. This is a good start to regulating your body temperature. Even if you do not feel the cold or heat, your body is still sensing it and responding to it. I see many individuals in the cold weather with their feet uncovered, no coat, blanket, etc. Typically, I am told, ‘I don’t feel the cold.’ That is true, but your body still responds to it. Hypothermia is the result.
Be prepared for going outside. Wheelchairs contain a lot of metal parts that retain cold and heat. Be sure you are protected by using a blanket and appropriate warm clothing. A coat should go around your whole body, not just across the front. A blanket smoothed from wrinkles might be used under your body if you will be out for a long period of time. This should be removed as soon as back in a temperature-regulated environment as you do not want to disrupt your skin dispersion equipment. When your body is not moving, you are not generating heat from within, so you might want to dress a bit warmer than others.
In the heat of the summer, you will want to dress cooler but be prepared to protect your body and eyes from the sun. Use sunscreen. Rash guard clothing, sunglasses, cooling towels, fans, wide-brimmed hats should be your style. Sit in the shade and take cooling breaks in air conditioning to help keep your body temperature steady.
Go from one temperature-controlled environment to another. You might be outside but stay out for short periods of time. You might be at an outdoor event where you will want to stay warm or cool by taking breaks in temperature-controlled areas. Have your vehicle started so it is warm or cooled prior to getting into it. Stay in temperature-controlled areas if you can.
Natural body reflexes Sweating does not typically occur in individuals with high-level spinal cord injury, particularly in the cervical region. However, every SCI is unique in many ways. Few individuals will sweat below the level of injury, not for body cooling or temperature regulation but as a misread signal from the brain. In higher-level injuries, it has been noted to be an unusual manifestation of Autonomic Dysreflexia (AD).
Shivering does not occur below the level of injury. This is because supra spinal innervation is not present. The connection between the detection of cold is different from warm. The sensation of cold is mostly detected in the skin. Why sweating might possibly occur, but shivering does not, probably has something to do with the skin receptors, but the link is unclear.
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Metabolic rate Fever is the result of metabolism working overtime. This is most often a response to internal infections. Unlike being warm from environmental temperature, this is a response that the body uses to heighten the metabolism to fight infection. Fever can be controlled with fever-reducing medication, cooling cloths and baths, and reduction of warm coverings.
Shivering Involuntary shaking of the body is a way for it to increase metabolism to warm itself. People shiver more the lower the level of injury. People with lower-level spinal cord injury might be able to warm their bodies with shivering, thereby controlling temperature.
You can control your body temperature by planning for the weather. If you become cold, you can drink warm fluids or soup, wrap up in blankets (avoid electric blankets as they can burn your skin without your knowing), or turn up the heat just a couple of degrees.
Some people have a hard time resetting their internal body temperature. This is because once the body temperature is affected by the environment, it can be difficult for the ANS to regulate. For some, sleeping or napping will rest the brain, allowing it to rest itself. Many individuals, especially with the higher-level injury, report this as the only way to they can reset their body temperature. Preparation can help stop the change in internal body temperature, which avoids further lifestyle modification with sleep. Nurse Linda
Pediatric Consideration: Children are more susceptible to environmental temperatures in general. Their metabolisms are working harder because their bodies are busy with the goal of growing. After spinal cord injury, this quick metabolism can slow.
The smaller the child, the larger the skin surface is on the head. Infants and small children have heads that are larger in proportion to adults. With adults, the focus is on keeping the body warm or cool, which just happens to include the head. For children, additional emphasis is placed on keeping the head warm or cool as well as the body. No matter the age, both head and body need attention to regulate body temperature, but you can see the subtle difference. Children should have appropriate headwear for cold and hot weather as well as body apparel.
Depending on your child’s developmental age, they might not be able to tell you if they are too cold or too hot or just feeling funny. Some activities divert children’s attention away from their physical well-being only by the nature of fun. That is why distraction is used so much in childcare. In body temperature regulation, however, you must be the support by making these decisions for your child to ensure their safety.