Extreme Temperatures Hit Older Bodies Differently — Here’s Why

A temperature that feels merely uncomfortable to a younger person can become a genuine physiological stress test for an older body.

And it's not just extreme heat.

Cold can be dangerous too.

As we age, some of the body's systems for controlling temperature become less responsive. We may sweat less efficiently, have a slower cardiovascular response to heat, produce less heat in the cold, and be less aware of how much our body temperature is changing.

Add certain medications, chronic health conditions, dehydration or limited access to heating and cooling, and the risk can rise considerably.

But there's an important qualification: getting older does not automatically make someone fragile.

Fitness, body composition and overall health can make a substantial difference in how well someone handles temperature extremes.

So what actually changes with age?

Your body has a thermostat — and it changes

Your body works remarkably hard to keep its internal temperature within a narrow range.

When you're hot, blood vessels near the skin widen and your body produces sweat. Blood flow to the skin helps move heat toward the surface, where it can escape.

When you're cold, blood vessels constrict to reduce heat loss, and your muscles can generate additional heat through shivering.

These responses don't disappear with age.

But they can become less effective.

A 2025 systematic review examining 141 studies found that older adults generally have lower sweat rates and slower onset of sweating, along with changes in metabolic rate and cardiovascular responses. In warm environments, these differences can reduce the body's ability to get rid of heat and increase heat storage.

A separate systematic review of heat tolerance in older adults found similar patterns: reduced sweating, less effective widening of skin blood vessels, altered cardiovascular and autonomic responses, impaired hydration and changes in the perception of temperature.

The result is that an older person can accumulate heat faster and become dehydrated more easily during significant heat exposure.

Heat can put extra strain on the heart

Heat isn't simply uncomfortable.

Your body has to work harder to get rid of it.

Blood vessels near the skin widen, increasing blood flow to the skin. The heart then has to move blood around to support both circulation and cooling.

Dehydration makes the problem worse because losing fluid reduces blood volume.

For an otherwise healthy older adult, the body may compensate successfully.

But if someone already has cardiovascular disease or another condition that limits the body's ability to respond, extreme heat can become a much bigger physiological challenge.

A 2026 global systematic review and meta-analysis examined 623 studies across six continents and found that high temperatures and heatwaves were associated with increased illness and mortality among older adults. The greatest risks were generally seen at more advanced ages and among people with additional vulnerabilities.

Cold creates a different physiological challenge

The body normally responds to cold by constricting blood vessels and increasing heat production.

Research has found that aging is associated with reduced cold-induced thermoregulation. Older adults can lose heat more readily and may produce less metabolic heat during cold exposure.

Muscle matters here.

Shivering is essentially involuntary muscle activity designed to generate heat. Because muscle mass and muscle function tend to decline with age, the body's ability to generate heat through this mechanism can also decline.

A 2025 review of thermal responses in older adults found that older people generally have lower skin temperatures in cold environments, particularly at the extremities, and that age-related changes in circulation, skin and nervous-system function can affect thermal responses.

That doesn't mean every older adult becomes highly vulnerable to cold.

It means the margin for error can become smaller.

You may not realize how cold or hot you are

This is one of the more interesting—and potentially important—changes.

Temperature perception can change with age.

That means an older person may not always recognize how much physiological stress their body is experiencing.

This matters in both directions.

Someone can become overheated without appreciating how serious the situation is.

Someone exposed to cold may not realize that their body temperature is falling to a dangerous level.

That's one reason the National Institute on Aging specifically warns that older adults can be more vulnerable to both heat and cold.

Medications can change the equation

Age itself isn't the only issue.

Medications can have a major effect on how the body handles temperature.

Some medications can interfere with sweating, alter blood pressure, affect hydration or change the body's ability to regulate temperature.

The National Institute on Aging specifically notes that older adults are more likely to have chronic medical conditions and take medications that can affect the body's response to heat.

That means two people of the same age can have very different levels of vulnerability.

It's one reason temperature warnings shouldn't be interpreted simply as:

"Everyone over 65 is in danger."

The real picture is more complicated.

Chronic disease matters too

Heart disease, lung disease, diabetes and kidney disease can all affect how the body responds to temperature stress.

For example, heat can increase cardiovascular workload while dehydration can reduce circulating blood volume.

Cold can cause blood vessels to constrict, increasing cardiovascular strain.

Respiratory conditions can also make extreme temperatures more difficult to tolerate.

A large systematic review of temperature-related health effects among adults 65 and older found that both higher and lower temperatures were associated with increased cardiovascular and respiratory mortality.

The study estimated that, in this population, each 1°C increase in temperature was associated with increased cardiovascular and respiratory mortality, while a 1°C decrease was also associated with increased risk.

The exact relationship varies by climate, population and the temperatures people are accustomed to.

There is no single temperature that is equally dangerous everywhere.

It's not just about how old you are

Here's the part that's easy to miss.

Chronological age is not the whole story.

Research on aging and temperature regulation has found that factors such as fitness, body composition and chronic disease can substantially influence thermal tolerance.

That means a healthy, physically active 70-year-old may respond very differently to a heat wave than a sedentary 70-year-old with multiple chronic conditions.

Age increases vulnerability.

It does not determine it.

That's an important distinction.

Why cold can be especially deceptive

People tend to think of hypothermia as something that happens outdoors in freezing weather.

It doesn't have to.

Older adults can become dangerously cold in environments that don't seem particularly cold to younger people.

The National Institute on Aging notes that older adults may not recognize that they are becoming dangerously cold, and hypothermia can occur in relatively cool conditions.

That's particularly relevant indoors.

A poorly heated home, prolonged inactivity, inadequate clothing or illness can gradually lower body temperature.

You don't necessarily need snow on the ground.

Heat and cold don't act exactly the same way

Population studies have found something interesting about temperature-related deaths.

The relationship is often U-shaped: mortality tends to be lowest within a relatively comfortable temperature range and rises as temperatures move substantially hotter or colder.

But heat and cold can have different time courses.

A large meta-analysis involving almost 13 million deaths among older people found that hot temperatures were associated with a roughly 2–5% increase in mortality for each 1°C increase during hot-temperature intervals.

Cold temperatures were associated with roughly a 1–2% increase in mortality for each 1°C decrease.

Cold effects could also persist for several days after exposure, whereas the heat effects in that analysis were more immediate.

These numbers should not be interpreted as a personal prediction of risk. They describe population-level associations across many studies and climates.

What should you actually do?

The answer isn't to become afraid of hot weather or cold weather.

It's to respect what extreme temperatures demand from your body.

During significant heat:

• Drink fluids regularly rather than waiting until you're very thirsty.
• Get into air conditioning or another cool environment when temperatures become excessive.
• Avoid strenuous activity during the hottest part of the day.
• Pay particular attention if you take medications that affect hydration, blood pressure or sweating.
• Don't assume that feeling "okay" means your body isn't under stress.

During significant cold:

• Keep your living space adequately heated.
• Dress in layers rather than relying on a single heavy garment.
• Don't ignore persistent shivering or unusual tiredness.
• Be particularly cautious if you have cardiovascular disease or other conditions affected by cold.
• Check on older friends or relatives who live alone during unusually cold weather.

And if you're unsure whether a medication could affect your response to heat or cold, ask your pharmacist or healthcare professional.

The bigger lesson

Aging doesn't suddenly break the body's thermostat.

But some of the mechanisms that keep us within a safe temperature range become less responsive. We may sweat less, our circulation may respond less efficiently, we may produce less heat in the cold, and our perception of temperature can change. Chronic disease, medications, dehydration and our environment can add additional stress.

That's why extreme temperatures deserve more respect as we get older. The goal isn't to become afraid of hot weather or cold weather. It's to understand that your body may be working considerably harder than you realize to keep you comfortable and safe.

Age increases vulnerability. It doesn't determine it.

The Watchdog takeaway

Extreme temperatures aren't just a comfort issue as you get older—they can become a physiological challenge.

Older adults generally have less effective responses to both heat and cold, but age isn't the whole story. Fitness, muscle mass, chronic disease, medications, hydration and living conditions can make a major difference.

The most useful lesson isn't "older people can't handle extreme temperatures."

It's this:

Know your vulnerabilities, pay attention to the weather, and don't wait until you feel terrible before taking the temperature seriously.

Your body is remarkably good at keeping its internal temperature stable. But when the environment pushes hard enough, it may need some help.