Heat stress and how to manage it.

With summer well and truly in full force, it’s important to think about those who are working outside in these conditions and the risk of heat stress. Heat stress occurs when the body becomes dehydrated and the core body temperature rises to around 40.5C. In hot conditions, the body works overtime and becomes stressed to keep itself at 37C. If left untreated, this can lead to heat stress – which, in the wrong conditions, is potentially life-threatening. It’s best to go to all measures to prevent heat stress.

How it happens:

The human body’s temperature rises during physical work but is controlled by cooling through the evaporation of sweat through the skin. However, if the body is dehydrated, a downward spiral occurs. First, there is limited water available for sweating and cooling the body. Secondly, the blood becomes too concentrated, which leads to impaired organ function.
Young children, the elderly, pregnant or breastfeeding women, and people with heart disease, high blood pressure or lung disease are at the highest risk. Anyone who lives and works on a farm is at risk in the hot conditions. In particular, shearers and those working physically hard in sheds during hot and humid weather, as well as those working in full protective clothing such as overalls.

What to look for: Signs of heat stress.

There are 3 main stages to heat stress; heat cramps, heat exhaustion and heat stroke. Early signs of heat stress include headaches, feeling sick, nausea, dizziness, weakness, heavy sweating, thirst and irritability. If these are ignored, the conditions can worsen to clumsiness, collapsing and convulsions. All these symptoms need immediate medical attention.

What to do: Prevention of heat stress.

Research has shown that workplace accidents are at their highest during the summer months, with rates increasing with the rise in temperature. The following steps can be taken to minimise the potential for heat stress when working in high temperatures.

1. Ice ingestion: eating crushed ice or frozen liquids acts as a heat sink in the body to lower the core body temperature to help improve performance in the heat.

2. Cooling: When possible, removing personal protective clothing or having a cooled area indoors can allow workers to better cool down on their breaks. Cooling vests have also proven to be very effective in minimising heat stress. Adequate airflow is critical and can be increased with cooling fans to help the body sweat to cool evaporatively.

3. Hydration: Hydrating with cool water or electrolyte drinks before commencing work is important to prevent heat stress. Rehydrating throughout the day and after work is also vital. Electrolyte drinks will ensure water is absorbed properly by the body.

4. Heat tolerance/acclimatisation and fitness: Exposing yourself to hot and humid conditions over time can build up a tolerance to it. Regular physical activity that results in lots of sweat can improve this tolerance and make the transition to a hot workplace more tolerable.

5. Work rate: Obviously, the harder you work, the more body heat you will produce. But each individual has different degrees of fitness. It’s important to adjust the rate of work to match each worker, allowing them to work at their own pace and adjust their workload to how they are feeling.

6. Nutrition: Loss of appetite in warmer weather is very common, but 6-8 hours without food is the limit when high sweat rates are encountered. It’s important to eat little and often to keep up essential nutrients and energy.

7. Sleep: Sleep is extremely vital for recovery, and quality uninterrupted sleep in a cool environment is important (not on site though).

8. Education: All employees should be trained and be aware of the signs and symptoms presented by heat stress, and taught how to act upon them.

9. Environmental Monitoring: Keep an eye on the upcoming weather to plan when appropriate work should be done and when rests should be given.

10. Monitoring workers: Make sure workers are keeping an eye on their skin and core body temperatures, and that they are drinking enough water. Also, ensure they aren’t overdoing it and putting their health at risk just to get jobs done.

11. Have a heat stress management policy: Put a policy in place detailing the responsibilities of employees and managers to prevent and manage heat stress for staff. This is an essential document for organisations that operate in hot conditions.