The National Weather Service’s Heat Index shows the risk of activity based on heat plus humidity.
Outdoor workers should build up to a full day in the heat to allow their bodies to acclimatize to it.
CDC
Behavior changes are another way of adapting to heat stress. Since midday is typically the hottest part of the day, it makes sense to avoid physical work and exercise then. When people are active, their bodies break down nutrients – carbohydrates, fats and protein – into energy. This powers movement and also generates metabolic heat, which adds to the body’s heat stress.
Taking advantage of shade is another important strategy. Heat radiating from the Sun adds to the stress produced by warm air temperatures. Staying in the shade can significantly reduce the external heat load on people who have to be outdoors during hot spells.
Many of the hundreds of deaths and hospitalizations that experts have attributed to the recent heat dome in the Northwest probably reflect that buildings there were less equipped to keep people cool than in hotter regions, and residents were less acclimatized to heat.
2020 was Phoenix’s hottest year on record, with 53 days reaching at least 110 F.
The old and young are most vulnerable
A healthy adult body can acclimatize to heat, but older people and children are less able to adjust. As people age, their cardiovascular systems change in ways that cause them to pump blood less effectively. This reduces the body’s ability to move heat to the skin to be transferred to the environment.
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Children and older adults may also have less active sweat responses, which can reduce their potential to cool off through sweating.
Humans can tolerate most areas of the Earth, but extreme heat requires extra steps. If there’s a heat wave in your local forecast, seek out shade and begin to acclimatize by increasing your activity gradually when things get too hot. Drink more fluids to account for increased fluid loss from sweat, while also making sure not to overhydrate. And avoid outdoor activity during the hottest hours of the day if possible.
Whether heat waves are humid or dry, they are health threats that everyone should take seriously.
JohnEric W. Smith, Associate Professor of Exercise Physiology, Mississippi State University
This article is republished from The Conversation under a Creative Commons license. Read the original article.
