by James Hubbard, M.D., M.P.H.

Pop quiz:

1. Why are some outdoor workers more prone to heat strokes after the first hot spell in early summer than later when it gets even hotter?
2. Why are there more heat strokes in Chicago when the temperature may be hotter elsewhere at the same time?

Answer:

Much has to do with your body having time to adapt, otherwise called acclimatization.  It takes between eight and 12 days for your body to acclimate to higher temperatures so when those hot days hit, you’re not ready.  The body acclimates to heat by:

• Triggering sweating a lower body temperatures and sweating more. The amount of total body sweat may double.  This is a great way to cool off by the water evaporating off your skin, but doesn’t work well with high humidity.  The sweat can’t evaporate.  A little breeze helps.
• Conserving sodium.  More sweat means more sodium (salt) loss, so your body starts making sweat that contains less sodium.
• Ramping up your heart’s efficiency by pumping more blood per heartbeat.  That way more blood can be delivered close to the skin surface for cooling.  The cooler blood then circulates to your inner organs. This is one reason the elderly and heart patients don’t do well (weaker heart pumping).
• Using body oxygen more efficiently so metabolism works a little slower.  Metabolism produces body heat.  More efficiency, less heat.

How to Stay Safe in the Heat

To prevent heat-related illness, go slow when the weather turns hot.

• Take breaks under the shade.
• Do the heavy work before 10 a.m. or after 4 p.m.
• Fan a little and be sure to drink lots of water.
• Maybe add a teaspoon of salt to the first quart or two of water, or drink an occasional sports drink with your water.

It is a fact that most people who work outside in the sun get dehydrated due to sweating and heat.  You can easily lose a quart of fluids per hour or more.  Dehydration leads to increased body heat (it’s a physiological thing).  Most people don’t become thirsty until they’re already dehydrated. So make it a point to drink fluids, thirsty or not.  On hot days with heavy work, you may need a quart or two of fluids per hour of work to keep up.  Sipping a little at a time is just as good, as long as you get drink the same net amount.

By the way, check on the elderly and chronically ill during hot spells.  Make sure they’re getting fluids and breezes.  When the humidity and heat soar, though, even fans don’t work well for cooling.  During heat waves, see if they can spend time in an air conditioned area around midday at least.  If nothing else, placing cool wet cloths on the neck or under the arms helps.

Does anyone have further suggestions to stay cool?

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As with all information on this site, this article cannot replace professional, personal medical advice. Read more here.

Tags: hot-weather safety

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This entry's content reflects the opinions and reporting of the author and not necessarily that of JHMFD. This entry was posted on Wednesday, June 10th, 2009 at 12:01 am and is filed under General Health, Home Care. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.