Chronic Low Temperature

Chronic low temperature is a pervasive husbandry-related condition that occurs when reptiles are consistently maintained at temperatures below their species-specific optimal range over extended periods. Unlike acute hypothermia, which represents a sudden and dangerous drop in body temperature, chronic low temperature involves prolonged exposure to suboptimal thermal conditions that gradually compromise the animal's health and physiological functions. This insidious condition is one of the most common yet frequently overlooked causes of illness in captive reptiles, often serving as the underlying factor behind numerous secondary health problems that bring reptiles to veterinary attention.

As ectothermic animals, reptiles depend entirely on external heat sources to regulate their body temperature and maintain normal metabolic functions. Every physiological process in a reptile's body, from digestion and nutrient absorption to immune function and cellular repair, operates optimally only within specific temperature ranges that vary by species. When environmental temperatures fall below these requirements consistently, even by seemingly small margins, the cumulative effects can be devastating to the animal's overall health and longevity. This makes proper thermal management one of the most critical aspects of reptile husbandry.

The impact of chronic low temperature extends to virtually every body system in affected reptiles. Immune function becomes progressively compromised, leaving the animal increasingly vulnerable to bacterial, viral, fungal, and parasitic infections that a healthy reptile would normally resist. Digestive efficiency plummets, leading to malnutrition even when adequate food is offered, as the animal cannot properly process and absorb nutrients. Metabolic processes slow dramatically, affecting everything from wound healing to reproductive function, and the reptile enters a state of chronic physiological stress that erodes its health reserves over time.

The good news is that chronic low temperature is entirely preventable and, when caught before severe secondary complications develop, highly treatable through proper husbandry correction. However, early detection requires keepers to understand both the subtle signs of thermal stress and the specific temperature requirements of their particular species. Because reptiles are masters at hiding illness, the effects of chronic low temperature often go unnoticed until significant damage has occurred, making education and proper enclosure setup essential components of responsible reptile keeping. Consultation with a reptile-experienced veterinarian is crucial both for treating affected animals and for preventing this condition through proper husbandry guidance.

The primary cause of chronic low temperature in captive reptiles is inadequate or improperly configured heating equipment within the enclosure. This can manifest in numerous ways, from using heat sources with insufficient wattage to heat the enclosure volume, to positioning heating elements incorrectly so that appropriate temperatures are not achieved in the areas where the reptile spends most of its time. Many keepers underestimate the heating requirements of their reptiles, particularly in larger enclosures or in rooms that experience significant temperature fluctuations. The use of inappropriate heating methods, such as relying solely on heat rocks which can cause burns while failing to warm the ambient air, or using colored bulbs that may not provide adequate infrared heat, compounds this problem.

Husbandry-related factors beyond heating equipment itself frequently contribute to chronic low temperature conditions. Enclosures placed in drafty locations, near exterior walls, or in basements or other cool areas of the home may never achieve appropriate temperatures regardless of the heating equipment used. Poor enclosure insulation, excessive ventilation, or screen tops that allow heat to escape too rapidly can all undermine heating efforts. Seasonal temperature changes often catch keepers off guard, with heating setups that were adequate in summer proving insufficient during colder months when household temperatures drop and the heating system must work harder to compensate.

Dietary factors can indirectly contribute to the effects of chronic low temperature, as reptiles maintained at suboptimal temperatures cannot properly digest food even when nutritionally appropriate meals are offered. This creates a dangerous cycle where the animal becomes increasingly malnourished, losing body condition and energy reserves that would help it cope with thermal stress. Additionally, reptiles that are already compromised by nutritional deficiencies, parasites, or other health issues are less able to thermoregulate effectively and may be more severely affected by temperatures that a healthy animal might tolerate.

Environmental stressors often accompany or exacerbate chronic low temperature conditions. Overcrowded enclosures may prevent subordinate animals from accessing the warmest basking areas. Inappropriate enclosure design with insufficient thermal gradient prevents reptiles from self-regulating their temperature throughout the day. Stress from handling, environmental changes, or the presence of perceived predators can cause reptiles to avoid basking areas even when they are available, leading to voluntary hypothermia that compounds any existing temperature deficiencies in the enclosure setup.

The pathophysiology of chronic low temperature involves the progressive shutdown of metabolic processes as enzyme function decreases at lower temperatures. Reptilian enzymes have optimal temperature ranges, and their activity drops significantly outside these ranges. As body temperature decreases, metabolic rate falls, immune cells become less active, digestive enzymes function poorly, and the animal enters a state of metabolic depression that, while similar to natural brumation in some species, becomes pathological when it occurs involuntarily and continuously. This metabolic slowdown means that energy stores are depleted more rapidly than they can be replenished, toxic metabolic byproducts may accumulate, and the animal's ability to respond to environmental challenges or infections becomes severely compromised.

Early warning signs of chronic low temperature are often subtle and easily overlooked by inexperienced keepers. Affected reptiles may show decreased activity levels, spending more time hiding or remaining motionless than is typical for their species. A gradual reduction in appetite is common, with reptiles showing less interest in food or taking longer to initiate feeding responses. The animal may seem lethargic or sluggish even during periods when it should be most active, and overall alertness may decrease. These early signs are frequently dismissed as normal behavior variation or attributed to other causes, allowing the condition to progress.

Common visible symptoms become more apparent as chronic low temperature continues to affect the reptile. Weight loss develops as the animal fails to properly digest and absorb nutrients, often visible as a reduction in body condition along the tail base, limbs, and temporal regions of the head. The skin may appear dull or discolored, and shed cycles may become irregular or incomplete as metabolic processes necessary for proper ecdysis are compromised. In some species, subtle color changes may occur, with animals appearing darker as they attempt to absorb more heat, or paler due to poor circulation and overall health decline.

Behavioral changes in reptiles suffering from chronic low temperature provide important diagnostic clues for observant keepers. Affected animals often show reduced interest in their environment, failing to investigate changes or respond to stimuli that would normally attract their attention. Basking behavior may paradoxically decrease as the animal becomes too weak or debilitated to move to warmer areas of the enclosure. Normal daily activity patterns become disrupted, with reptiles remaining hidden during periods they would typically be active. Social behaviors in normally interactive species diminish, and animals may become withdrawn or unresponsive to keeper presence.

Physical signs of chronic low temperature accumulate as the condition progresses. Respiratory issues often develop as immune suppression allows opportunistic bacteria to colonize the respiratory tract, manifesting as open-mouth breathing, mucus around the nostrils, or audible respiratory sounds. Skin infections, scale rot, and mouth rot become increasingly common as the compromised immune system fails to control normal bacterial flora. Muscle wasting becomes visible as the body breaks down tissue to maintain essential functions. Eyes may appear sunken due to dehydration, as thermoregulatory-impaired reptiles often fail to drink adequately.

Symptom progression in chronic low temperature typically follows a predictable pattern, though the timeline varies depending on the severity of temperature deficit and the species involved. Initial appetite reduction and lethargy give way to visible weight loss and reduced activity over weeks to months. As immune suppression takes hold, secondary infections begin to appear, often starting in areas of minor injury or natural bacterial load such as the mouth, respiratory tract, or skin. These secondary infections may become the presenting complaint when the animal is finally brought for veterinary care, masking the underlying temperature-related cause.

Emergency symptoms requiring immediate veterinary intervention include complete refusal to eat for extended periods appropriate to the species, severe lethargy where the reptile fails to respond to stimulation, visible respiratory distress including open-mouth breathing or gasping, significant dehydration indicated by wrinkled skin or sunken eyes, and any signs of systemic infection such as swelling, discharge, or unusual odors. A reptile that cannot right itself when turned over, shows neurological abnormalities, or exhibits severe weakness represents a critical emergency that requires immediate care from a reptile-experienced veterinarian. These severe symptoms indicate that the chronic condition has progressed to a life-threatening stage requiring aggressive intervention.

Physical examination by a reptile-experienced veterinarian is essential for diagnosing chronic low temperature and its associated complications. The veterinarian will assess the animal's overall body condition, looking for signs of muscle wasting, dehydration, and weight loss that indicate prolonged metabolic compromise. Careful examination of the skin, eyes, oral cavity, and respiratory system helps identify secondary infections that commonly accompany chronic thermal stress. The veterinarian will also evaluate the animal's responsiveness, muscle tone, and neurological function to assess the severity of metabolic depression. A thorough physical examination often reveals multiple abnormalities that, taken together, point to chronic husbandry issues as the underlying cause.

Diagnostic tests support the clinical findings and help evaluate the extent of physiological damage. Blood work, including a complete blood count and biochemistry panel, can reveal immune suppression, organ dysfunction, and metabolic disturbances. Elevated white blood cell counts may indicate secondary infections, while abnormal kidney or liver values can signal organ damage from chronic metabolic stress. Radiographs may be taken to evaluate for pneumonia, assess bone density if metabolic bone disease is suspected as a concurrent condition, or identify other abnormalities. Fecal examination checks for parasites, which often proliferate when immune function is suppressed.

Husbandry review is perhaps the most critical component of diagnosing chronic low temperature and should be conducted thoroughly before or alongside veterinary examination. The veterinarian or an experienced reptile consultant will ask detailed questions about enclosure setup, heating equipment, temperature ranges achieved, and how temperatures are monitored and maintained. Ideally, keepers should bring temperature logs and photographs of the enclosure setup. A proper husbandry review often reveals the source of thermal inadequacy, whether it be incorrect equipment, improper placement, inadequate monitoring, or environmental factors that compromise heating effectiveness. This review is essential not only for diagnosis but for developing an effective treatment plan.

Differential diagnosis is important because the symptoms of chronic low temperature overlap with many other reptile health conditions. The veterinarian must consider and rule out primary infectious diseases, parasitic infestations, nutritional deficiencies, organ disease, and other metabolic disorders that could produce similar clinical signs. However, it is equally important to recognize that chronic low temperature often underlies or accompanies these other conditions, serving as a predisposing factor that allowed secondary problems to develop. A comprehensive diagnostic approach considers chronic low temperature as both a primary condition requiring correction and as a contributing factor to other identified health issues, ensuring that treatment addresses root causes rather than just visible symptoms.

Husbandry correction forms the foundation of treatment for chronic low temperature and must be addressed before or alongside any other therapeutic interventions. The heating system must be evaluated and upgraded to provide species-appropriate temperatures throughout a proper thermal gradient. This typically involves ensuring adequate basking spot temperatures, appropriate ambient temperatures in both warm and cool zones, and possibly the addition of supplementary heat sources such as ceramic heat emitters or radiant heat panels for nighttime temperature maintenance. Temperature monitoring equipment should be installed or upgraded, with digital thermometers and temperature guns providing accurate readings in multiple enclosure locations. The goal is to establish and maintain optimal temperatures twenty-four hours a day, every day.

Medical management focuses on addressing the secondary complications that have developed due to chronic thermal stress. Bacterial infections commonly require antibiotic therapy, with drug selection based on culture and sensitivity results when possible. Respiratory infections may require nebulization treatments in addition to systemic antibiotics. Fungal or parasitic infections are treated with appropriate antimicrobial medications. It is crucial to remember that drug metabolism in reptiles is temperature-dependent, so medications will be more effective once proper temperatures are restored. Your reptile veterinarian will select medications appropriate for reptile physiology and calculate doses based on the species and individual animal.

Supportive care is essential for reptiles recovering from chronic low temperature and its effects. Fluid therapy addresses dehydration that commonly accompanies this condition, administered either orally, subcutaneously, or intravenously depending on the severity of dehydration and the animal's condition. Temperature optimization is maintained carefully, with some veterinarians recommending slightly elevated temperatures to support immune function and recovery. Nutritional support may include assist feeding or supplementation if the animal is not eating voluntarily, using species-appropriate formulas and methods. Probiotics may be recommended to help restore gut flora compromised by the metabolic slowdown.

Surgical options are rarely needed specifically for chronic low temperature but may be necessary to address severe secondary complications. Abscesses may require surgical drainage and debridement. Severely infected or necrotic tissue, particularly in cases of advanced scale rot or mouth rot, may need surgical intervention. Any surgical procedure on a reptile must be performed with careful attention to temperature management, as anesthesia and recovery both require maintained thermal support. Post-surgical care for reptiles is complicated by their temperature-dependent healing, making optimal husbandry even more critical during recovery.

Species-specific treatment considerations must guide the therapeutic approach, as temperature requirements and tolerances vary significantly between reptile species. Desert species generally require higher basking temperatures and can tolerate wider temperature swings, while tropical forest species often need more moderate but consistent warmth. Aquatic and semi-aquatic species have temperature requirements for both water and basking areas that must be addressed. Nocturnal species may need different approaches to heating that provide warmth without disruptive light. The reptile veterinarian will tailor recommendations to the specific species, taking into account natural history, known tolerances, and individual animal factors.

Treatment timeline for chronic low temperature recovery extends over weeks to months, significantly longer than comparable conditions in mammals. Reptilian metabolism operates on a fundamentally different timescale, meaning that both the damage from chronic cold and the recovery process occur gradually. Initial stabilization may show improvement within days to weeks as temperatures normalize and hydration is restored, but full recovery of immune function, digestive efficiency, and overall condition takes much longer. Secondary infections may require extended antibiotic courses. Keepers should expect a marathon rather than a sprint, with gradual improvement punctuated by possible setbacks that require patience and continued diligent care. Regular veterinary rechecks help monitor progress and adjust treatment as needed.

Recovery timeline for reptiles affected by chronic low temperature varies considerably based on the duration and severity of thermal stress, the species involved, and the extent of secondary complications that developed. Mild cases caught early may show significant improvement within two to four weeks of husbandry correction, with appetite and activity returning to normal as the animal's metabolism stabilizes at proper temperatures. More severe or prolonged cases require months of recovery, during which the animal gradually regains lost body condition, immune function normalizes, and secondary infections resolve. Some animals, particularly those with significant organ involvement or severe infections, may require six months or more to fully recover. Patience is essential, as rushing the process or expecting rapid improvement often leads to disappointment and potential setbacks.

Post-treatment husbandry optimization goes beyond simply correcting the original temperature problem to creating an ideal thermal environment that supports recovery and long-term health. This includes establishing a proper thermal gradient that allows the animal to behaviorally thermoregulate throughout the day, with basking temperatures at the upper end of the species-appropriate range to support immune function and healing. Temperature monitoring should become routine, with daily checks and logging to catch any equipment failures or environmental changes promptly. The enclosure setup should be evaluated holistically, addressing any other husbandry deficiencies in lighting, humidity, nutrition, or environment that may have accompanied the temperature issues or could compromise recovery.

Prognosis factors influencing recovery outcome include the duration of chronic low temperature exposure, the animal's age and prior health status, the severity of secondary infections or organ damage, and the keeper's ability to provide and maintain optimal husbandry going forward. Younger, otherwise healthy animals with shorter exposure duration and minimal secondary complications have excellent prognoses with proper care. Older animals, those with significant immune compromise, or those with established organ damage face more guarded outcomes. Animals that have developed severe respiratory infections, septicemia, or significant organ dysfunction may recover with intensive care but may also suffer lasting health effects that reduce their longevity or quality of life.

Long-term monitoring and follow-up are essential components of complete recovery from chronic low temperature. Regular veterinary rechecks allow assessment of treatment progress, adjustment of medications, and early detection of any complications or setbacks. At home, keepers should monitor weight regularly using a gram scale, track food intake and fecal output, observe behavior and activity levels, and watch for any signs of recurring problems. Temperature logging should continue indefinitely as part of routine husbandry. Many veterinarians recommend a recheck examination and bloodwork once the animal appears clinically recovered to confirm that internal parameters have normalized. Establishing a relationship with a reptile-experienced veterinarian for ongoing wellness care helps prevent future problems and ensures early intervention if issues arise.

Proper husbandry setup is the cornerstone of preventing chronic low temperature in captive reptiles and should be established before acquiring any reptile. This begins with thorough research into the specific temperature requirements of the intended species, including optimal basking temperatures, ambient temperature ranges for warm and cool zones, and nighttime temperature requirements. The enclosure should be sized appropriately to allow establishment of a proper thermal gradient, and heating equipment should be selected with enough capacity to achieve required temperatures even during the coldest months of the year. Multiple thermometers placed throughout the enclosure provide accurate monitoring, and temperature-controlling devices such as thermostats or rheostats help maintain consistent temperatures regardless of ambient room conditions.

Dietary prevention, while not directly preventing temperature-related issues, supports overall health and resilience against the effects of any temperature fluctuations that occur. Species-appropriate nutrition ensures the animal has adequate energy reserves and immune resources to cope with environmental stressors. Proper supplementation with calcium and vitamins supports metabolic functions that become stressed under suboptimal temperatures. A well-nourished reptile is better able to maintain its health during minor temperature fluctuations and recover more quickly if exposure to low temperatures does occur. Feeding schedules should account for temperature, as reptiles should not be fed when enclosure temperatures are below the range necessary for proper digestion.

Quarantine protocols for new reptiles should include careful attention to temperature management alongside disease surveillance. New animals should be housed in enclosures with verified proper temperatures and monitored closely for any signs of health issues that may have developed during shipping or prior housing. The stress of acquisition and transport makes new reptiles particularly vulnerable to the effects of temperature problems, so ensuring optimal thermal conditions from day one supports successful acclimation. Quarantine enclosures should be fully equipped and tested before the animal arrives rather than set up hastily upon acquisition.

Regular health monitoring allows early detection of any problems, including early signs of chronic thermal stress before significant complications develop. Keepers should weigh their reptiles regularly and track weight trends over time, as gradual weight loss often indicates developing problems. Behavioral patterns should be observed and noted, with changes in activity level, basking behavior, appetite, or responsiveness prompting investigation of potential causes including temperature issues. Regular assessment of body condition, skin quality, and overall appearance helps identify subtle changes that might otherwise go unnoticed until problems become severe.

Veterinary check-ups with a reptile-experienced veterinarian provide professional assessment of reptile health and husbandry that complements home monitoring. Annual wellness examinations allow the veterinarian to evaluate the animal's condition, discuss husbandry practices, and identify any early signs of problems. These visits establish a baseline of normal values for the individual animal and build a relationship with a veterinarian who will be familiar with the animal's history if health issues arise. Many reptile health problems, including those related to chronic low temperature, can be prevented or minimized through proper veterinary guidance on husbandry and early intervention when problems are detected. Keepers should not wait until their reptile is visibly ill to seek veterinary care.

Ongoing husbandry requirements for reptiles susceptible to or recovering from chronic low temperature center on maintaining consistent, species-appropriate temperatures at all times. This requires reliable heating equipment, typically including primary heat sources and backup options in case of equipment failure. Heating equipment should be checked regularly for proper function and replaced before failure when signs of wear appear. Seasonal adjustments may be necessary as ambient room temperatures change throughout the year, with heating capacity that was adequate in summer potentially falling short during winter months. Power outages present a significant risk, so keepers should have contingency plans that may include battery backup systems, chemical heat packs, or arrangements to relocate animals during extended outages.

Environmental management and monitoring should become an integral part of daily reptile care routines. Temperature checks at multiple points in the enclosure, ideally logged in a simple journal or app, help track conditions over time and identify trends or problems early. Both thermometers and heating equipment should be verified periodically for accuracy, as equipment drift can cause gradual temperature changes that might otherwise go unnoticed. The enclosure location should be considered seasonally, with awareness of how drafts, sun exposure, and household heating patterns affect the reptile's environment. Any changes to the enclosure or the room it occupies should prompt reassessment of thermal conditions.

Health indicator monitoring extends beyond temperature to encompass all aspects of reptile wellness that may be affected by or indicate thermal stress. Regular weighing using a gram scale appropriate to the animal's size provides objective data on body condition trends. Appetite should be noted at each feeding, including not just whether the animal eats but how enthusiastically and how much. Activity patterns, basking behavior, and overall alertness provide behavioral indicators of health status. Shedding frequency and quality reflect metabolic health, as do fecal output and consistency. Any changes in these parameters should prompt review of husbandry conditions including temperature, as subtle thermal problems often manifest first through these indirect indicators.

Quality of life considerations become particularly important for reptiles that have experienced chronic low temperature and may have lasting health effects. Animals that have suffered significant immune compromise or organ damage may require modified care going forward, potentially including more conservative temperature management, modified diet, or ongoing medical support. Keepers should honestly assess their animal's quality of life based on behavior, appetite, activity, and apparent comfort, working with their veterinarian to ensure that care decisions prioritize the animal's wellbeing. Reptiles that fail to thrive despite optimal care may have sustained damage that limits their recovery potential.

Long-term care planning acknowledges that many reptile species live for decades with proper care, requiring sustained commitment to optimal husbandry throughout their lives. Equipment will need replacement, enclosures may need upgrading as animals grow, and household circumstances may change in ways that affect the reptile's environment. Planning ahead for these eventualities helps ensure consistent care over the animal's lifetime. Keepers should consider factors such as backup care arrangements during travel or emergencies, financial planning for veterinary care and equipment needs, and how life changes might affect their ability to maintain proper husbandry. This long-term perspective helps prevent the lapses in care that can allow chronic low temperature and other husbandry-related problems to develop.

High-risk species for chronic low temperature problems include tropical reptiles that have evolved in consistently warm environments and have limited tolerance for temperature variation. Chameleons are particularly vulnerable due to their highly specialized care requirements and sensitivity to environmental conditions, with even moderate temperature drops significantly impacting their health. Green iguanas and other tropical lizards require consistently warm basking and ambient temperatures that many keepers fail to provide adequately, especially in cooler climates or during winter months. Many tropical gecko species, including crested geckos and day geckos, need stable warm temperatures that can be challenging to maintain. Tropical python and boa species, while covered in separate snake-specific resources, face similar challenges. Young reptiles of all species are especially vulnerable to temperature problems due to their smaller body mass and limited energy reserves.

Captive versus wild-caught considerations affect susceptibility to chronic low temperature in several ways. Wild-caught reptiles often experience significant thermal stress during capture, holding, and transport before ever reaching the pet trade, potentially arriving with compromised immune systems that make them more vulnerable to further temperature insults. These animals may also harbor parasites or subclinical infections that become active when immune function is suppressed by inadequate temperatures. Captive-bred reptiles from reputable breeders, while generally healthier at acquisition, can still suffer from chronic low temperature if proper husbandry is not maintained. However, they typically lack the pre-existing health burdens that make wild-caught animals especially vulnerable.

Species-specific susceptibilities vary based on natural history, body size, and physiological adaptations. Small-bodied reptiles lose heat more rapidly than larger animals and have less thermal inertia, making them more immediately affected by temperature drops. Species from stable tropical environments may lack the physiological adaptations to cope with temperature variation that species from more variable climates possess. Desert species accustomed to extreme temperature swings may tolerate brief cool periods better than forest species adapted to constant warmth, but still require adequate basking opportunities to raise their temperatures daily. Understanding the specific needs and vulnerabilities of each species is essential for providing appropriate care and recognizing when temperature-related problems may be developing.

Commonly co-occurring conditions with chronic low temperature reflect the systemic impact of prolonged thermal stress on reptile health. Respiratory infections are perhaps the most frequent secondary complication, as immune suppression allows opportunistic bacteria to colonize the respiratory tract and multiply unchecked. Stomatitis, commonly known as mouth rot, develops as normal oral bacteria overwhelm compromised local immune defenses. Parasitic infections, both internal and external, may flare or become established more easily in temperature-stressed animals. Bacterial and fungal skin infections, including scale rot, take advantage of weakened immune surveillance. These concurrent infections often become the presenting complaint that brings the animal to veterinary attention, masking the underlying temperature problem that enabled their development.

Conditions with similar symptoms to chronic low temperature include various infectious diseases, parasitic infestations, and metabolic disorders that can produce lethargy, appetite loss, and general decline. Primary respiratory infections, viral diseases, heavy parasite burdens, and systemic bacterial infections can all cause symptoms that overlap with chronic thermal stress. Metabolic bone disease in early stages may manifest as decreased activity before more obvious skeletal signs develop. Organ disease, including renal and hepatic dysfunction, produces nonspecific signs of illness. Nutritional deficiencies can cause lethargy and failure to thrive. Differentiation requires thorough diagnostic workup and careful evaluation of husbandry, though it is important to recognize that chronic low temperature may coexist with or contribute to any of these conditions.

Secondary complications of chronic low temperature can become serious health threats in their own right, requiring specific treatment alongside husbandry correction. Respiratory infections may progress to pneumonia if not addressed promptly and effectively. Systemic bacterial infections can develop into septicemia, a life-threatening condition requiring aggressive treatment. Severe stomatitis can progress to osteomyelitis of the jaw bones. Parasitic infections allowed to proliferate can cause significant organ damage. Nutritional deficiencies develop as poor digestion prevents nutrient absorption, potentially leading to metabolic bone disease or other deficiency syndromes. The interconnected nature of reptile diseases means that chronic low temperature, by compromising immune and metabolic function, sets the stage for a cascade of secondary problems that can ultimately prove more immediately life-threatening than the original temperature deficit.