24 WESTERN PALLET
Treating All Workers the Same in the Heat? That Could Be Risky
Special to WPA, by Nicole Moyen, Vice President of Research and Development at Kenzen and heat stress blogger.
When it comes to planning for the prevention of heat-related injuries & illnesses among an entire workforce, a one-size plan does not fit all.
The research behind managing worker safety under hot working conditions has largely been based on studies of young, healthy men, which means that other populations – women, older adults, and people with other risk factors – will need different accommodations if a heat safety program is to be effective.
Sex, age, health status, and other factors can impact risk
According to researchers who study how heat affects workforces, “…existing guidelines adopted and recommended for use by government agencies worldwide to protect the public and workers also assumes a “one size fits all” approach to protect human health. These guidelines generally prescribe protective measures (e.g., heat advisories, exposure limits) using models defined by the assessment of heat strain in young and/or relatively healthy adults. They fail to consider key factors such as sex, age, health status, and other factors, which can markedly alter a person’s tolerance to
heat, thereby leaving a large segment of the population under-protected…” (1)
For example, a man working at the same relative work rate as a woman will typically have a higher sweat rate. This is because men generally have a larger body-surface-area-to-mass ratio than women.
Given that sweating is the main way a body gets rid of body heat, this higher sweat rate among men means that their body temperature will be lower in hot-dry (low humidity) climates. As a result of this higher sweat rate & lower body temperature, men will likely be able to work for a longer period of time than women. However, in hot-humid climates where sweat can’t evaporate as easily and therefore doesn’t cool you down, women will likely be able to work for a longer period of time than men. This is because men will continue to sweat more than women, but this sweat won’t be cooling them down, and in fact, they’ll just lose a lot of body water. The effect: in hot-humid environments, men will become dehydrated more quickly than women, and see a faster increase in core body temperature – the primary trigger of heat-related injuries and illnesses.
Older workers more susceptible to heat stress
Another natural factor that can vary the susceptibility of heat-related injuries and illnesses among workers is age. After age 35, the body’s ability to dissipate heat, primarily through sweating, declines. As a result, older adults tend to have higher core body temperatures than younger adults, when working at the same rate in the heat. This difference between older and younger individuals can be minimized with heat acclimatization and endurance training.
In addition, some people are able to acclimatize faster and tolerate heat better than others; a portion of this appears to be attributable to genetic makeup.
Moreover, there are various diseases that can impair the body’s ability to effectively thermoregulate, such as various cardiovascular diseases (e.g., hypertension), sweat gland disorders (e.g., Type I and Type II diabetes), skin disorders (e.g., psoriasis), and metabolic disorders. Individuals with these diseases will be at increased risk for heat-related injuries and illnesses.