THERMOREGULATION THERMOREGULATION THE PROCESS OF MAINTAINING CORE BODY

THERMOREGULATION

THERMOREGULATION THE PROCESS OF MAINTAINING CORE BODY TEMPERATURE WITHIN AN OPTIMAL PHYSIOLOGICAL RANGE

Thermoregulation �Process that balances heat production and heat loss - Maintain relatively constant core temperature �Heat produced = heat lost - Hyperthermia and hypothermia - pathophysiologic consequences to altered thermoregulation

Thermoregulation Hypothermia Severe Moderate Mild <30°C 30°-34°C 34°-36°C (80°F) (80°-93. 2°F) (93. 2°-96. 8°F) Normothermia 36. 5°-37. 2°C (97. 7°-98. 96°F) Hyperthermia Hyperpyrexia >37. 2°C (98. 96°F) >41. 5°C (106. 7°F) Scope of Thermoregulation Ranges from Hypothermia, to Normothermia, to Hyperthermia (Source: Giddens, 2013, St. Louis, MI: Mosby)

Thermoregulation �Factors Affecting Heat Production and Conservation → Metabolic activity - basal metabolic rate (BMR) → Muscle activity → Chemical thermogenesis – epinephrine release → Sympathetic stimulation – stress response and peripheral vasoconstriction → Fever

Thermoregulation � Factors Affecting Heat Loss → Radiation → Conduction → Convection → Vaporization ■ Insensible water loss ■ Insensible heat loss → Vasodilation → Reduced muscle activity → Increased respirations

ANTECEDENTS REGULATION OF BODY TEMPERATURE WHAT FACTORS PLAY A ROLE IN REGULATING BODY TEMPERATURE? WHY? WHAT HAS TO HAPPEN IN ORDER FOR THERMOREGULATION TO OCCUR?

Regulation of Body Temperature ● Conscious Responses �Putting on clothing, turning on fan ● Thermoreceptors in Shell and Core ▪ Peripheral thermoreceptors �Skin has more receptors for cold than warmth �Skin chilled → shivering, sweating, vasoconstriction ▪ Central thermoreceptors �Located in the spinal cord, abdominal organs, and hypothalamus

Regulation of Body Temperature HYPOTHALAMIC INTEGRATOR CONTROLS CORE TEMP ● � ACTIVATES RESPONSES TO LOWER OR RAISE BODY TEMPERATURE BASED ON INFORMATION RECEIVED FROM THERMORECEPTORS � SENSORS DETECT HEAT � COLD SENSORS STIMULATED

Regulation of Body Temperature Control � The hypothalamus controls body temperature and signals for mechanisms to increase heat production or facilitate heat loss. HYPOTHALAMUS HYPOTHALMUS Decreased Temperature ● Blood vessels constrict ●Sweat glands less active ●Skeletal muscles contract, causing shivering Increased Temperature ● Blood vessels dilate – causing a flushed appearance to skin ● Sweat glands become more active

Factors Affecting Body Temperature �Age �Diurnal variations �Exercise �Hormones �Stress �Environment - Extremes affect thermoregulation - Newborns homeothermic

PAIR SHARE Pick a Partner Discuss developmental considerations affecting thermoregulation in the following groups and provide a rationale for your answer. 1. Infants 2. Young children 3. Older adults

Risk Factors for Alterations in Thermoregulation ● Populations at Risk - Infants and young children - Older adults - People living in very cold or very hot climates - Low socioeconomic status - Homeless ● Individual Risk Factors - Impaired cognition - Underlying health conditions - Genetics - Recreational and occupational exposures

Alterations � Pyrexia - Body temperature above usual range - Hyperpyrexia - Febrile - Afebrile � Hypothermia - Excessive heat loss - Inadequate heat production to counteract loss - Impaired hypthalamic thermoregulation

Physical Assessment �Measuring body temperature �Body temperature measured in degrees on two scales - Celsius (centigrade) - Farenheit - Conversion formulas: ■ From °F to °C (Farenheit temperature – 32) x 5/9 ■ From °C to °F (Celsius temperature x 9/5) + 32

Physical Assessment, continued �Sites for measurement - Oral - Rectal - Axilla - Tympanic membrane - Forehead �Advantages and disadvantages of sites

Physical Assessment, continued �Types of thermometers - Mercury in glass → no longer used - Electronic thermometer → fast and sanitary - Basal thermometer → used for fertility - Hyperthermia thermometer → 81 - 108° - Chemical disposable thermometers - Infrared thermometers �Developmental considerations

Assessment �Comprehensive History - Biographical information - Health history - Family history (malignant hyperthermia) - Recent illnesses or injuries - Environmental exposures

Assessment �Physical and Physiological - Alterations in body temperature - Hyperthermia - Hypothermia �Diagnostic Tests - Complete blood count (CBC) with differential - Imaging studies → for suspected head trauma

Interventions �Maintain thermoregulatory mechanisms by reducing risk factors: - Environmental Control and Shelter ▪ Elderly and young infants need warmer environment ▪ Infants and children should wear hats ▪ Maintain optimal temperature in home - Adequate Hydration - Physical activity

PAIR SHARE Pick a Partner 1. Take your partner’s temperature and record it. 2. Convert °F to °C and back. 3. One student march in place for 5 minutes, and the other student sits quietly. 4. Retake temperatures and compare results. - Who has the highest temperature? - Connect exercise, increase in temperature, and risk for elderly in both hot and cold environment