How do heat health alerts work and what do the different levels mean?

Thermal health alerts are in effect throughout England until 6:00 p.m. BST on Wednesday.

Amber warnings have been issued for East Midlands, West Midlands, east of England, London and southeast.

A less severe yellow warning is in place for the northeast, the northwest, the Yorkshire and the Humber and the South West.

Alerts warn the public when high temperatures have a potential health risk.

The wether alert service is managed by the UK Health Security Agency (UKHSA) and the Met Office.

It includes both heat and health health alerts.

Thermal health alerts are published between June 1 and September 30 and cold health alerts are published between November 1 and March 30.

In addition to warning the public, the system sends advice directly to NHS England, government and health professionals during unfavorable periods of time.

Alerts are classified according to severity and include:

• Weather conditions of the headlines expected in the coming days
• Details on how weather conditions will affect each region
• Links to additional information, advice and advice

The system was designed to help reduce the disease and deaths during periods of hot and cold time.

The level of alert is based on forecasts and data from the Office.

There are four levels ranging from green (the least severe) to red (the most serious):

Green

Green is the normal level, when advice is given on how people should prepare to answer if temperatures increase or decrease.

YELLOW

Yellow alerts are issued for hot or cold periods of time that are likely only to affect those who are particularly vulnerable, for example the elderly or those who suffer from existing health problems.

Amber

Amber alerts are issued in situations that could potentially put the whole population in danger. The NHS can see increased demand on general practitioners and ambulances, for example.

Travel disturbance is also likely.

Red

A red alert is the most serious.

It is issued in situations when hot or cold time would be a significant risk for life, even for the healthy population, and could cause critical national infrastructure failures, such as power outages or closed roads and lines.

As the body becomes warmer, the blood vessels open. This leads to a drop in blood pressure and makes the heart harder to push the blood around the body.

This can cause mild symptoms such as rash in heat or swollen feet, as blood vessels become fleeing.

At the same time, sweating leads to the loss of liquids and salt and, above all, the balance between them in the body changes.

This, combined with lowered blood pressure, can lead to heat exhaustion and heat stroke. Symptoms include:

• dizziness
• nausea
• fainting
• confusion
• muscle cramps
• headache
• sweating
• fatigue

If the blood pressure drops too far, the risk of heart attacks increases.