How does the heat impact health?

With the UK experiencing increasingly hot summers, many of us are finding that the heat feels a little more intense than we’re used to. When temperatures rise and stay high, it can take a real toll on our health.

Not only does excess heat make us feel hot and uncomfortable. Prolonged exposure to heat can worsen existing conditions and affect how our bodies function day to day.

At EssexPrivateGP, we’re seeing more people asking how to stay well during hot weather, especially those managing chronic illnesses, older adults, and families with young children.

So, let’s take a closer look at what heat does to the body, who’s most at risk, and how to stay healthy while the sunshine lasts.

Why hot weather affects the body

Our bodies are good at regulating temperature, but there’s a limit to how much they can cope with, especially during a heatwave. When it’s hot, we naturally sweat more to try and cool down. That means we lose more fluid than usual, and if we don’t replace it, dehydration can set in quite quickly. The heart has to work harder to pump blood around the body, and your core temperature can rise if the body isn’t able to cool itself down properly.

According to the World Health Organization, extreme heat doesn’t just make you feel tired or sluggish, it can exacerbate existing health conditions, particularly cardiovascular, respiratory, and kidney disorders. People living with asthma, COPD, high blood pressure, or heart conditions may find their symptoms flare up when the weather heats up. For those with diabetes, staying hydrated is especially important to keep blood sugar levels stable.

Even people in good general health can experience heat-related problems like heat exhaustion or, in more severe cases, heatstroke. Symptoms can include dizziness, headaches, nausea, muscle cramps, or confusion, especially if you’ve been outside in the sun or doing physical activity. The WHO offers this advice if you’re feeling unwell during a heatwave.

Who’s most at risk, and why it matters

Some groups are more vulnerable to heat-related illness than others. Older adults, young children, and people with chronic illnesses tend to be less able to regulate body temperature or may not recognise the early signs of dehydration or overheating. Those who are pregnant, taking certain medications, or recovering from illness may also find their heat tolerance is lower than usual.

Urban environments can make things worse. Cities often retain heat, especially overnight, and buildings without proper ventilation can trap warm air, making it harder for your body to recover from daytime temperatures. For anyone living alone or without easy access to cool, shaded spaces, this can be a particular challenge.

If you or someone you know falls into one of these more vulnerable groups, it’s worth keeping a closer eye on them.

Staying safe and cool

When it comes to staying safe in the heat, a few practical steps go a long way. One of the most important is to stay out of the heat during the hottest part of the day, usually between 11am and 3pm. If you can, aim to do errands or exercise early in the morning or later in the evening, when the air is cooler.

Keeping your environment cool helps too. Closing curtains on sun-facing windows during the day, using a fan, and opening windows in the early morning or late evening can help maintain a more comfortable indoor temperature.

And of course, stay well hydrated. Even if you don’t feel particularly thirsty, it’s important to drink water regularly throughout the day. Try to avoid too much caffeine or alcohol, as they can dehydrate you. Eating lighter meals and snacks like salads, fruits, and vegetables, can help too.

If you’re finding the hot weather difficult to manage or want advice on how it might affect an existing condition, book an appointment with EssexPrivateGP.