Watch for the dangers of heat stress during harvest


Harvest is underway across Canada and the heat is as variable as the crops this year.

In parts of Ontario, the third week of August was the coolest (21.2 degrees) since June, according to The Weather Network. Further east, New Brunswick has been hit with high temps. along with a mix of storms, which have brought hail and torrential downpours. In the west, parts of southern Alberta, Saskatchewan and Manitoba have hit the high 30s on a regular basis this summer.

With high temps in many parts of the country during harvest, there is an elevated risk for heat exposure. What are the signs you, as a producer, should look for to protect yourself?

Dr. Denise Koh is the chief occupational medical health officer for Province of Manitoba. She says some of the minor signs to watch out for when it comes to heat exposure are:

  • Swelling in the hands, feet and ankles
  • Muscle cramps
  • Heat rash

More serious signs of heat exhaustion are:

  • Light headedness
  • Dizzyness
  • Confusion
  • Headache
  • Nausea
  • Vomiting
  • Rapid heart rate

Koh says when a person has heat exhaustion their core temperature is elevated but less than 40 degrees — regular body temperature is around 37. Heat stroke can occur when your body hits 40 degrees or higher.

“That’s the most severe heat related illness which can be potentially life threatening,” she says. Dr. Koh added a person with heat stroke could be experiencing these symptoms:

  • Loss of consciousness
  • Seizures
  • Hallucinations
  • Mood swings: confused to very aggressive

She says the chances of heat stress, exhaustion, or stroke, while in a vehicle, such as a combine or tractor pulling a grain cart, can increase rapidly. This is because the windows in the vehicle act like in a greenhouse.

“So what happens, particularly in direct sunlight, temperatures can spike up to 20 degrees in a short period of time and can go up to even 50 degrees or higher,” she says.

In order to combat the heat while working, she says have lots of water nearby, keep hydrated and mist yourself. Use your air conditioning, if you’re lucky enough to have it, limit the amount of time outside (as best as you can) and go inside or out of the sun when need be.

Proper clothing is a key factor in maintaining your body core temperature. Just like you would when avoiding pesky mosquitos, wear light coloured clothing while on the job in the heat.

“If you have to wear work clothes that don’t really give you the breathability of the fabric, that’s when you might have to take more rest breaks,” she says.

Dr. Koh says it’s also always recommended to wear the proper sun screen and to be sure to re-apply every two hours as your body sweat lowers the sunscreen’s effectiveness. As a side note, she says, if mosquitos are prevalent in your neck of the woods, be sure to put the sun screen on first, before you apply bug repellent.

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