Behind the whiteboard #7 | Hypothermia: The Cold Truth Every New Zealander Should Know.

I (Jodie) remember one hike where the day started with clear blue skies and only a light breeze. Despite checking the forecast before heading out, low cloud rolled in, the wind picked up, and a steady rain soon followed.

Even though I wasn't far from shelter, I was surprised by how quickly I went from feeling comfortable to feeling cold and miserable. My mindset shifted from taking in the scenery to simply staying warm. I found myself walking faster, hunching my shoulders against the wind, counting down the distance back to shelter.

I wasn't in any immediate danger. But the experience made me realise something important: the cold can creep up on you long before you think you're in trouble. And that's exactly how hypothermia works.

So What Actually Is Hypothermia?

The word itself gives it away. Hypo means low or below normal. Thermia means heat or temperature. Put together, hypothermia literally means a lower-than-normal body temperature.

What happens inside the body

A healthy person's core body temperature is usually around 37°C. Hypothermia occurs when the body's core temperature falls below 35°C, making it difficult for the body to function normally.

Your body is constantly producing heat to keep your organs working properly. When you're exposed to cold temperatures, your body immediately tries to protect itself.

Blood vessels near the skin narrow to reduce heat loss, and your muscles begin to shiver to generate warmth. These responses help maintain your core temperature for a period of time.

However, if the body continues losing heat faster than it can produce it, the core temperature begins to fall.

As the core temperature falls:

• The brain slows down, affecting thinking and decision-making.

• Muscles become weaker and less coordinated.

• Heart rate and breathing may slow.

• The body's ability to generate heat decreases.

• Vital organs begin to struggle to function effectively.

Without treatment, severe hypothermia can lead to unconsciousness, cardiac arrest, and death.

Important to Note: A person with severe hypothermia may not realise how sick they are, making it important for others to recognise the warning signs.

What Does It Look Like?

In the early stages, the signs can be easy to miss, especially if you're busy, moving, or focused on getting somewhere.

Mild hypothermia (35–32°C): Shivering, feeling cold, pale or cool skin, difficulty concentrating, fatigue or drowsiness, clumsiness or poor coordination.

Sound familiar? On that hike, I was ticking a few of those boxes without really registering it. I was shivering slightly, moving clumsily over the wet track, and my thinking had narrowed down to one thing: get back to the car.

As the condition worsens, the signs become harder to ignore.

Moderate to severe hypothermia (below 32°C): Shivering may actually stop (which can feel deceptively like improvement), slurred speech, confusion or unusual behaviour, poor decision-making, difficulty walking, slow breathing, reduced level of consciousness.

If you're seeing these signs in someone, they need urgent medical attention. Don't wait to see if they warm up on their own.

Who Is Most at Risk?

Hypothermia doesn't only happen on mountain summits or in extreme conditions. It can affect anyone when the weather turns, and they're not prepared for the change.

There are a few groups most at risk, though:

Outdoor enthusiasts such as trampers, hunters, mountain bikers, and runners can quickly become hypothermic when weather conditions change unexpectedly. New Zealand weather doesn't give much warning.

Water-based recreation faces an added risk. Cold water removes body heat much faster than cold air. Boaties, swimmers, kayakers, and surfers are particularly vulnerable, even on days that don't feel that cold.

Elderly people often have a reduced ability to regulate body temperature. Combined with poorly insulated housing and high heating costs, winter at home can be just as dangerous as being outdoors. If cost is a barrier to keeping warm, the Winter Energy Payment is available from May to October to help with heating costs. It's automatically paid to eligible beneficiaries and superannuitants, but it's worth checking the MSD website to confirm eligibility.

Infants and young children lose heat more quickly than adults and may not be able to tell you they're dangerously cold. With little ones, you have to watch for the signs yourself.

What To Do If You're Worried About Someone

If you think someone might be hypothermic, here's what to do while you're waiting for help or getting them to safety.

Move them to a warm, sheltered environment as soon as possible. Remove wet clothing and replace it with dry layers. Wrap them in blankets, a sleeping bag, or whatever insulating material you have.

If they're fully awake and able to swallow safely, a warm drink can help. Avoid rapid heating methods like hot baths, which can sometimes cause more harm than good. Keep monitoring them closely.

Anyone showing moderate-to-severe signs needs urgent medical attention. Call 111.

A Little Preparation Goes a Long Way

Dress in multiple layers. Carry a waterproof outer layer when you're heading outdoors. Keep spare dry clothing in your pack or your car. Check the forecast before you head out, and take it seriously even on days that look fine.

At home, heat your house adequately throughout winter and check in regularly on elderly family members, friends, and neighbours during cold snaps.

The Bottom Line

Hypothermia doesn't just happen during extreme adventures. It can affect anyone enjoying the outdoors when the weather turns, and they're not prepared. It can happen at home. It can happen to the people you love.

That hike I mentioned taught me that the cold doesn't always come with a warning. One moment you're enjoying the day, and the next you're hunching into the wind, counting your steps, wondering how you got so cold so fast.

A little preparation, the right clothing, and an eye on the forecast can make all the difference.

Stay warm, stay dry, stay active, but don't underestimate the weather.