Growing human evidence suggests that repeated extreme heat may accelerate biological aging. Studies in Germany, Taiwan, the United States, and China have independently linked greater heat exposure with faster epigenetic or clinical measures of biological age.[1][2][3][4][5]
At the same time, controlled experiments show age-related changes in heat dissipation across adulthood. In severe heat, older age can mean a greater rise in core temperature and less sweating, while fitness, health, and access to cooling modify the response.[6][9]
The science does not support converting one heatwave into a fixed number of “years aged.” Biological-age measures are biomarkers, and researchers are still studying how persistent these heat-related changes are. The more useful conclusion is that repeated heat exposure is becoming relevant to healthy aging, especially from midlife onward.
What counts as extreme heat?
There is no single temperature that defines dangerous heat for every person and every place. The body's heat load depends on air temperature, humidity, sun exposure, wind, activity, exposure time, and whether the night brings meaningful cooling.
Humidity matters because sweat cools you only when it can evaporate. The heat index combines temperature and relative humidity to estimate how hot conditions feel to the human body. Local climate matters too. A temperature that is routine in one region may create far more strain in a place where people, homes, and infrastructure are less adapted.
This is why a forecast temperature alone cannot tell you how hard your body will work. A long humid afternoon, a hot bedroom, and an outdoor workout can create very different thermal demands at the same air temperature.
What does extreme heat do to your body?
Your body responds to heat by moving more blood toward the skin and producing sweat. Skin blood vessels widen so heat can move from the core toward the surface. Sweat can then carry heat away as it evaporates.
Those cooling systems are effective, but they are not free. More skin blood flow increases cardiovascular demand. Sweating removes water and electrolytes. If fluid losses grow, circulating blood volume can fall. The heart may need to beat faster to support both cooling and the rest of the body.
Once heat gain outpaces heat loss, core temperature rises. Fatigue, headache, dizziness, nausea, dehydration, and heat illness can follow. Controlled studies also show measurable kidney stress and changes in gastrointestinal permeability during severe experimental hyperthermia.[13][26]
For healthy aging, the important point is broader: heat is a whole-body physiological stressor. The strain depends on both the environment and the body's ability to respond.
CELLSHE synthesis
Heat acts on two timescales
Acute heat strain
Timescale: minutes to hours
- Core and skin temperature
- Sweating and skin blood flow
- Heart rate and blood pressure
- Hydration and circulating volume
- Kidney and gastrointestinal stress
- Heat exhaustion and heat stroke at the severe end
Evidence maturity: strong controlled physiology and extensive epidemiology.
Cumulative heat burden
Timescale: repeated days to years
- Epigenetic-age acceleration
- Clinical biological-age acceleration
- Sleep disruption during hot periods
- Changes in daily mobility and activity
- Long-term cognitive associations in some populations
Evidence maturity: biological aging is convergent but mainly observational or longitudinal. Sleep evidence is stronger. Mobility and cognitive evidence are still developing.
Heat illness and biological aging are different outcomes. The newer research asks whether repeated environmental heat leaves longer-term biological signatures, including in people who never develop heat stroke.
Sources: biological-aging cohorts [1]–[5]; heat physiology [6]–[10]; sleep, mobility, and cognition [14]–[17].
Can extreme heat accelerate biological aging?
Several human studies now point in that direction. The strongest reason to take the finding seriously is replication across different populations and different measures of biological age.
Chronological age is simply time since birth. Biological-age models try to estimate how a person's molecular or physiological profile compares with what is expected at a given age. Some use DNA methylation patterns, often called epigenetic clocks. Others combine clinical biomarkers into a biological-age estimate.
These tools do not measure the same thing. A one-year change in one clock cannot be treated as equivalent to a one-year change in another. For a deeper explanation of what these tests can and cannot tell you, see our guide to how biological age is measured.
Biological age also extends beyond any single clock. Our Hallmarks of Aging guide explains the cellular processes researchers use to describe aging biology. Our review of whether aging can be reversed explains why a biomarker can move without proving whole-body rejuvenation.
What matters here is direction. Across multiple studies, people with greater or more sustained heat exposure tended to show faster aging on the measure used in that study.[1][2][3][4][5]
cellshe evidence synthesis
Five human populations, one emerging pattern
| Study | Population | Heat exposure | Aging measure | Main finding |
|---|---|---|---|---|
| Ni et al., 2023 [1] | Germany, KORA; 1,725 participants at F4 and 1,877 at FF4 | Medium- and long-term ambient temperature | Five epigenetic-age measures | Higher medium- and long-term temperature exposure was associated with acceleration across several clocks. |
| Chiu et al., 2024 [2] | Taiwan Biobank; 2,084 adults | Ambient temperature and heat index across 1- to 180-day windows | Eight DNA-methylation age algorithms | Higher temperature and heat index were associated with greater age acceleration, with stronger associations in several longer exposure windows. |
| Choi & Ailshire, 2025 [3] | United States; 3,686 adults aged 56+ | Neighborhood heat-index exposure from short windows through six years | PCPhenoAge, PCGrimAge, DunedinPACE | Longer-term heat exposure was associated with acceleration across all three aging measures. |
| Chen et al., 2025 [4] | Taiwan; longitudinal cohort of 24,922 adults, 2008–2022 | Cumulative heatwave exposure | Clinical biomarker biological-age acceleration | Greater cumulative heatwave exposure was associated with higher biological-age acceleration. Adaptation appeared over time, but the association remained. |
| Xu et al., 2026 [5] | China, CHARLS; 2,318 middle-aged and older adults | Heatwave events and days using 12 definitions | Klemera-Doubal biological age | Greater heatwave exposure was associated with greater biological-age acceleration across longitudinal analyses. |
The replication is more informative than any single effect size. Five populations using different methods point toward a relationship between repeated heat and faster biological-aging measures.
Sources: Ni et al. [1]; Chiu et al. [2]; Choi & Ailshire [3]; Chen et al. [4]; Xu et al. [5].
The 24,922-person Taiwan study adds an important detail. People appeared to adapt gradually across 15 years, yet cumulative heatwave exposure still tracked with faster biological aging. Manual workers, rural residents, and communities with fewer air conditioners were more susceptible.[4]
One limitation is worth remembering. Long-term cohorts estimate environmental heat far better than each person's true thermal dose. They cannot perfectly capture every hour spent in air conditioning, at work, in shade, or outdoors.[3][4]
That finding makes the story less fatalistic. The weather matters, but so do actual exposure, work conditions, cooling, and adaptation.
Why does heat get harder to tolerate as you age?
Heat tolerance changes across adulthood. There is no physiological switch that suddenly flips at 65.
A systematic review of 24 studies found that older adults often show reduced sweating and skin blood-flow responses, weaker cardiovascular and autonomic adjustments, altered hydration, and greater heat storage during hot conditions.[6] A broader review of 147 controlled studies reached the same general conclusion while highlighting how much of the historical evidence came from men.[7]
Midlife matters here. In a 2024 experiment, critical core-temperature limits and heart-rate thresholds shifted toward lower environmental conditions with age in both hot-dry and warm-humid heat. Across adulthood, the decline was linear in hot-dry conditions and curved in warm-humid conditions.[8]
A new 2026 Lancet Planetary Health modelling study went one step further. It combined experimentally derived heat limits for young adults, adults aged 40–59, and adults 60+ with climate and population projections. Using age-specific limits produced much larger estimates of future exposure to conditions where the body can no longer maintain thermal balance than models that apply young-adult tolerance to everyone.[22] This is a population projection, not a personal temperature cutoff.
Controlled human data
Heat tolerance changes across adulthood
Greater rise in core temperature for each additional 10 years of age.
95% CI: +0.04 to +0.13°C.
Lower whole-body sweat rate for each additional 10 years of age.
95% CI: −10 to −1 g/m²/hour.
Higher whole-body sweat rate per +10 mL/kg/min higher VO₂peak.
Lower end-exposure heart rate per +10 mL/kg/min higher VO₂peak.
Fitness helped, but it did not erase the age-related rise in core temperature. This is useful for midlife training decisions: fitness is part of heat resilience.
Source: Brown et al., 2026 [9].
These changes help explain why the same walk, commute, garden session, or outdoor workout can feel different at 50 than it did at 25. Fitness, medications, chronic conditions, body size, and heat acclimatization can move that response in either direction.
Keeping strength and aerobic fitness through midlife still matters. Our strength-training guide for healthy aging explains how to build a realistic weekly baseline.
CELLSHE evidence framework
The Heat–Aging Framework
1. Thermal load
Temperature + humidity + duration + sun + activity + nighttime cooling.
2. Heat-dissipation capacity
Sweating + skin blood flow + cardiovascular adjustments. Capacity tends to change across adulthood.
3. Physiological strain
Higher core temperature + dehydration + cardiovascular load + kidney and gastrointestinal stress.
Direct biological pathway
Repeated heat exposure has been associated with faster epigenetic and clinical biological-age measures in several human populations.
Evidence: convergent, mainly observational and longitudinal.
Indirect healthy-aging pathway
Hot conditions can disrupt sleep and may reduce exercise, daily movement, and time spent outside the home.
Evidence: strong for heat and sleep; developing for mobility and long-term cognitive outcomes.
Modifiers across the framework: cooling access, acclimatization, cardiorespiratory fitness, health status, medications, body morphology, age, sex, occupation, housing, and local environment.
Heat vulnerability is modifiable and cannot be predicted from chronological age alone.
CELLSHE synthesis based on biological-aging studies [1]–[5], thermoregulation and organ-strain research [6]–[13][26], and sleep, mobility, sex, and adaptation evidence [14]–[21].
How does heat affect your heart and blood pressure?
Heat can change blood pressure, but it does not simply raise it in everyone. Skin blood vessels widen during heat exposure, which can lower vascular resistance and blood pressure. At the same time, heart rate rises as the cardiovascular system works to maintain circulation and move heat toward the skin.
Dehydration adds another layer. Losing fluid through sweat can reduce circulating blood volume. That may contribute to lightheadedness or a blood-pressure drop, especially when standing. Exercise increases the demand because muscles and skin compete for blood flow at the same time.
A large cardiovascular meta-analysis found that higher temperatures and heatwaves were associated with greater cardiovascular mortality risk across populations. Adults over 65 and women were among groups with higher heat-related risk in pooled analyses.[12] A 2026 meta-analysis covering 623 studies also found higher morbidity and mortality during high temperatures and heatwaves among older populations.[11]
If you take blood-pressure medicines, diuretics, or other prescriptions that affect fluid balance or temperature regulation, do not change them on your own because of a heatwave. CDC recommends making a medication plan with a clinician for hotter days rather than stopping medicines abruptly.[27]
Why do hot nights matter for sleep and recovery?
Higher nighttime temperatures generally reduce sleep quality and sleep duration. A 2024 systematic review found a consistent negative relationship between higher indoor or outdoor temperatures and real-world sleep, with stronger effects during the hottest periods and in vulnerable groups.[14]
A small controlled study helps show what that can look like. Sixteen adults over 65 slept in rooms at 27°C and 30°C. At 30°C, total sleep time fell by 26.3 minutes, sleep efficiency fell 5.5 percentage points, REM sleep fell 5.3 minutes, and awake time increased by 27 minutes.[15]
The experiment was small, so its exact numbers are not population averages. Its direction matches the broader sleep literature.
This matters in midlife because sleep already becomes a more visible health priority for many women. Hot bedrooms can add another source of disruption alongside work stress, caregiving, perimenopause, or night sweats. Our evidence review on how much sleep adults need explains the sleep-duration side in more detail.
Current studies do not show that sleep disruption is the mechanism causing heat-related biological-age acceleration. It is better understood as a separate pathway through which hot conditions can erode recovery.
What happens to exercise and daily movement during a heatwave?
A normal workout becomes a larger thermoregulatory task in hot weather. Exercise produces internal heat while the environment is already making heat loss harder. Heart rate, sweating, fluid needs, and perceived effort can all rise.
The practical response is not to abandon movement for the summer. Change the timing, intensity, and environment. A morning walk, indoor strength session, shaded route, or shorter workout can preserve the habit while lowering heat strain.
Heat may also change movement outside formal exercise. A 2026 pilot study tracked 82 older adults by smartphone and found that summer life-space mobility began shrinking once average daily temperature rose beyond about 28.8°C (83.8°F).[16] The sample was small and not representative of every older adult, so the finding needs replication.
Still, the idea is useful. Heat can affect healthy aging both through direct physiological stress and by pushing walking, social activity, errands, and exercise out of the day.
Does extreme heat affect women differently after menopause?
Environmental heat and a menopausal hot flash are different physiological events. Menopause changes thermoregulatory signaling, and hot flashes are linked to menopause-related neural and hormonal changes in temperature control. Hot environments and hot nights can add another thermal challenge for women with vasomotor symptoms.[19]
The evidence does not support a simple claim that menopause makes every woman unable to tolerate heat. Studies of sweating and heat loss after menopause are mixed, and age, fitness, body composition, health, medications, and the environment all influence the response.[19]
Sex may still matter. In a 2024 study of 72 adults aged 40–92, older women reached critical environmental heat limits at lower conditions than age-matched men after accounting for age and metabolic rate.[18] Other experiments do not find a large independent sex effect for every heat-response measure.
For a woman in her 40s, 50s, or 60s, the useful message is personal rather than categorical. Pay attention to how hot weather interacts with sleep, hot flashes, exercise, medications, and recovery. Your response may change before you fit anyone's definition of “older.”
Who is most vulnerable to repeated heat exposure?
Chronological age is one risk factor, not a complete measure of heat resilience. Risk tends to rise when several sources of vulnerability overlap.
- Older age: heat-dissipation responses often become less efficient with age.[6]
- Heart, kidney, metabolic, or other chronic conditions: heat can add physiological demand to systems with less reserve.[11]
- Some medications: diuretics, cardiovascular drugs, and other medicines can affect hydration, circulation, sweating, or heat perception.[6][27]
- Outdoor or manual work: activity and exposure time increase total heat load. Manual workers were more susceptible in the 15-year Taiwan study.[4]
- Limited cooling: housing and access to air conditioning change the heat dose a person actually experiences.[4]
- Lower fitness or limited mobility: fitness improves some thermoregulatory responses, while mobility can determine access to cooler environments.[9]
- Living alone or social isolation: there may be nobody nearby to notice worsening heat illness or help reach a cooler place.[23]
This is why “I am only 52” or “I am fit for my age” is not enough to judge a hot day. Personal health, exposure, and cooling matter just as much as the number on a birthday cake.
Can your body adapt to heat?
Yes. Adults can acclimatize to repeated heat exposure, and that capacity remains present later in life.
A systematic review of short-term heat acclimation in adults over 50 found that eight of 12 included studies reported lower core temperatures after acclimation protocols.[20] A 2026 controlled study found that seven days of passive hot-water heat acclimation lowered resting core temperature and increased sweat rate in healthy adults aged 60–78.[21]
Those studies show physiological plasticity. They do not establish a home hot-water protocol for every older adult, especially for people with cardiovascular disease, blood-pressure problems, or medicines that alter heat responses.
The practical lesson is simpler. Heat tolerance can improve with acclimatization and fitness, but environmental limits still exist. Cooling, hydration, timing, and sensible activity choices remain useful even when you are well adapted.
How to reduce cumulative heat stress
The most useful heat strategy is to make decisions before you are already overheated. In the United States, the National Weather Service HeatRisk scale gives a practical daily signal from 0 to 4. It considers local heat, duration, and the likelihood of health impacts.[24][25]
Printable decision tool
Your Heat Day Decision Guide
0 · Green | Little to no added heat risk
Keep your normal routine. Check air quality before longer outdoor activity.
1 · Yellow | Minor heat risk
If heat affects you easily, prioritize water and cooling. Pay attention to how you feel.
2 · Orange | Moderate heat risk
Move longer walks or workouts toward the coolest part of the day. Use shade and breaks. Plan time somewhere air-conditioned if needed.
3 · Red | Major heat risk
Move strenuous or prolonged outdoor activity indoors, shorten it, or reschedule when possible. Make cooling a priority.
4 · Magenta | Extreme heat risk
Make cooled indoor space your default when possible. Avoid unnecessary outdoor exertion. If you do not have air conditioning, identify a cooled public location.
Make five decisions before the hot part of the day
1. When will I move?
Choose the coolest available time for walking, running, gardening, commuting, or outdoor training.
2. Where can I cool down?
Know where you can spend several hours in air conditioning if your home becomes too hot.
3. Do I have water with me?
Bring water and drink regularly. If a clinician has given you fluid restrictions, follow that plan instead of generic hydration advice.
4. Is air quality also poor?
Heat and air pollution can overlap. Check both before a long outdoor session.
5. Who should I check on?
Think about older relatives, neighbors living alone, and anyone with limited mobility or chronic health conditions.
Fan rule
CDC advises using fans for body cooling only when indoor temperature is below 90°F (32.2°C). Above that, use air conditioning or get to a cooler location.
Change the timing, intensity, and environment before heat forces you to.
Sources: CDC heat-health guidance [23] and HeatRisk guidance [24]; National Weather Service HeatRisk [25].
Cooling is not a sign that your body failed to adapt. It reduces the thermal load your cardiovascular and thermoregulatory systems have to manage. The long-term aging studies also suggest that access to cooling can influence who carries the greatest cumulative burden.[4]
Healthy aging is built from repeatable choices. The same principle applies to heat as it does to sleep, movement, and nutrition. Our broader healthy-aging guide puts those daily priorities into one framework.
When does heat become an emergency?
Stop activity and get somewhere cool if you become dizzy, weak, nauseated, very tired, or develop a headache during heat exposure. These are among the symptoms CDC lists when the body is overheating.[23]
Confusion, altered mental status, slurred speech, loss of consciousness, seizures, or very high body temperature can signal heat stroke. In the United States, call 911. Move the person to a cool or shaded area, remove outer clothing, and start cooling while emergency help is on the way.[28]
Heat illness is easier to prevent when the day is planned early. That is especially important if you live alone, take medications that affect fluid balance, care for an older relative, or know that hot weather already affects your sleep or blood pressure.
Frequently asked questions
Can extreme heat make you age faster?
Growing human evidence suggests that repeated heat exposure may accelerate biological aging. Studies from Germany, Taiwan, the United States, and China have linked greater heat exposure with faster epigenetic or clinical biological-age measures.[1][2][3][4][5] These biomarkers do not tell us that one heatwave permanently adds a fixed number of years to a person's body.
Does heat affect biological age?
Yes, in the biological-age measures used by several observational and longitudinal studies. The studies used different DNA-methylation clocks and clinical biomarker algorithms, so their numerical age estimates should not be compared as one common unit.[1][5]
Why does heat get harder to tolerate as you age?
Age can reduce several parts of the body's heat-dissipation response. Research describes lower sweating in many conditions, reduced skin vasodilation, altered cardiovascular adjustments, and greater heat storage in older adults.[6] Controlled evidence also suggests these changes develop across adulthood rather than beginning on one birthday.[9]
Does heat raise blood pressure?
Heat can affect blood pressure, but it can also lower it. Skin blood vessels widen to release heat, while sweating can reduce circulating fluid volume. Heart rate often rises to maintain circulation. Your response depends on hydration, medications, health, and activity level.
Does hot weather affect sleep?
Yes. A systematic review found that higher indoor and outdoor temperatures generally reduce sleep quality and quantity, with stronger effects during the hottest periods and in vulnerable populations.[14]
Does menopause make you more sensitive to hot weather?
Menopause can change thermoregulation and make hot conditions harder to manage for some women, especially when hot flashes or night sweats are present. It does not create a universal level of heat intolerance. Age, fitness, body composition, health, medications, and environment all matter.[18][19]
Can exercise improve heat tolerance?
Cardiorespiratory fitness appears to improve some heat responses. In a 2026 controlled study, higher VO₂peak was associated with greater sweating and a lower end-exposure heart rate. Fitness did not eliminate the age-related increase in core temperature.[9]
Can you adapt to extreme heat?
The body can acclimatize to repeated heat exposure, including later in life. Research in adults over 50 shows improvements such as lower core temperature and better sweating after controlled acclimation protocols.[20][21] Acclimatization does not remove the need for cooling and sensible heat decisions.
What should extreme heat change about healthy aging?
Treat extreme heat as part of the environment your healthy-aging plan has to work within. The evidence now reaches beyond heat stroke. Repeated heat exposure has been associated with faster biological-aging measures, while controlled experiments show that the same hot environment can create more physiological strain as we move through adulthood.
For women in midlife, the useful response is practical. Protect sleep on hot nights. Keep moving, but shift exercise when the heat load is high. Know how your medications and health conditions affect heat. Use cooling early. Pay attention to how menopause and hot flashes change your own comfort and recovery.
Healthy aging also means reducing avoidable strain so your body has more room to recover, adapt, and keep doing the things that matter.
For the wider routine around sleep, movement, strength, protein, metabolic health, and other midlife priorities, use CELLSHE's free Aging Well After 40 field guide.
Scientific references
- Ni W, et al. Associations between medium- and long-term exposure to air temperature and epigenetic age acceleration. Environment International. 2023;178:108109. DOI: 10.1016/j.envint.2023.108109.
- Chiu KC, et al. Exposure to ambient temperature and heat index in relation to DNA methylation age: A population-based study in Taiwan. Environment International. 2024;186:108581. DOI: 10.1016/j.envint.2024.108581.
- Choi EY, Ailshire JA. Ambient outdoor heat and accelerated epigenetic aging among older adults in the US. Science Advances. 2025;11(9):eadr0616. PMID: 40009659.
- Chen S, et al. Long-term impacts of heatwaves on accelerated ageing. Nature Climate Change. 2025;15:1000–1007. DOI: 10.1038/s41558-025-02407-w.
- Xu D, et al. Heatwave Exposure Accelerates Biological Aging via Metabolic Dysregulation. Cyborg and Bionic Systems. 2026;7:0602. DOI: 10.34133/cbsystems.0602.
- Núñez-Rodríguez S, et al. Heat Tolerance in Older Adults: A Systematic Review of Thermoregulation, Vulnerability, Environmental Change, and Health Outcomes. Healthcare. 2025;13(21):2785. DOI: 10.3390/healthcare13212785.
- Bach AJE, et al. Experimental research in environmentally induced hyperthermic older persons: A systematic quantitative literature review mapping the available evidence. Temperature. 2023. DOI: 10.1080/23328940.2023.2242062.
- Cottle RM, et al. Critical environmental core temperature limits and heart rate thresholds across the adult age span (PSU HEAT Project). Journal of Applied Physiology. 2024. DOI: 10.1152/japplphysiol.00117.2024.
- Brown HA, et al. Impact of age, cardiorespiratory fitness, and regular physical activity on physiological strain and cognitive performance during a 6-h extreme heat exposure. Journal of Applied Physiology. 2026;140(6):1721–1731. PMID: 42141767.
- McKenna ZJ, et al. Age alters the thermoregulatory responses to extreme heat exposure with accompanying activities of daily living. Journal of Applied Physiology. 2023. PMID: 37410904.
- Günsche J, et al. Mortality, morbidity and healthcare costs of short-term high temperatures and heatwaves exposure in older populations: a global systematic review and meta-analysis. Environment International. 2026;208:110129. PMID: 41679084.
- Liu J, et al. Heat exposure and cardiovascular health outcomes: A systematic review and meta-analysis. The Lancet Planetary Health. 2022;6:e484–e495. PMID: 35709806.
- McKenna ZJ, et al. Kidney Function Biomarkers During Extreme Heat Exposure in Young and Older Adults. JAMA. 2024;332(4):333–335. Full text.
- Chevance G, et al. A systematic review of ambient heat and sleep in a warming climate. Sleep Medicine Reviews. 2024;75:101915. PMID: 38598988.
- Yan Y, et al. Experimental study of the negative effects of raised bedroom temperature and reduced ventilation on the sleep quality of elderly subjects. Indoor Air. 2022;32:e13159. PMID: 36437666.
- Tan J, et al. Ambient Temperature and Life-Space Mobility in Older Adults: A Smartphone-Based Pilot Study. Innovation in Aging. 2026;10(5):igag027. PMID: 42088387.
- Choi EY, Lee H, Chang VW. Cumulative exposure to extreme heat and trajectories of cognitive decline among older adults in the USA. Journal of Epidemiology and Community Health. 2023;77:728–735. PMID: 37541774.
- Leach OK, et al. Sex differences in heat stress vulnerability among middle-aged and older adults. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology. 2024. PMID: 39005081.
- Gombert-Labedens C, et al. Effects of menopause on temperature regulation. Temperature. 2025;12(2):92–132. PMID: 40330614.
- Cole E, et al. Short-term heat acclimation protocols for an aging population: Systematic review. PLOS ONE. 2023;18:e0282038. DOI: 10.1371/journal.pone.0282038.
- Deshayes TA, et al. Heat acclimation improves the neural control of body temperature during heat stress in older adults. The Journal of Physiology. 2026;604:4968–4983. DOI: 10.1113/JP290417.
- Kong Q, Vecellio DJ, Huber M, et al. Exceeding human heat tolerance in a warming, ageing world: a global projection modelling study. The Lancet Planetary Health. Published online August 17, 2026:101494. DOI: 10.1016/j.lanplh.2026.101494.
- Centers for Disease Control and Prevention. About Heat and Your Health. Updated July 20, 2026. CDC heat-health guidance.
- Centers for Disease Control and Prevention. How to use the HeatRisk Tool and Air Quality Index. CDC HeatRisk guidance.
- National Weather Service. NWS HeatRisk: Highlighting Impactful Heat in the Seven Day Forecast. NWS HeatRisk.
- McKenna ZJ, Atkins WC, Wallace T, et al. Gastrointestinal permeability and kidney injury risk during hyperthermia in young and older adults. Experimental Physiology. 2025;110(1):79–92. DOI: 10.1113/EP092204. PMID: 39417775.
- Centers for Disease Control and Prevention. Heat and Medications: Guidance for Clinicians. Updated September 18, 2025. CDC medication guidance.
- National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention. Heat-related Illnesses. Updated March 3, 2026. CDC/NIOSH heat-illness guidance.
Editorial note: CELLSHE uses primary human studies, systematic reviews, and current public-health guidance where possible. Long-term heat and biological-aging research is still developing, so biological-age biomarkers are described as measured signals rather than proof of years of life gained or lost.
