The most recent heat wave may have passed, but summer is still in full swing -- which means heat-related health alerts. While these issues are not directly related to diabetes, diabetes can confound a heat-related health issue, making it harder to recognize and treat. Heat-related symptoms can mimic sugar-related symptoms and vice-versa, so it is in our best interests to know our normal ranges and reactions to the greatest degree possible.

The most basic heat issue is hydration. For some of us, dehydration will cause our blood glucose levels to drop; for others, it will cause those readings to rise. For some of us, the physical stress of dehydration will, at one point or another, trigger an adrenaline response and its associated glycogen release, leading to u-shaped curves (think "Dawn Phenomenon").

If left to develop, the combination of heat and dehydration (or heat and unbalanced hydration) can lead to heat exhaustion. The symptoms listed on sites such as WebMD and MedicineNet suggest to me that "heat exhaustion", like "diabetes", is an umbrella term for a number of distinct heat-related changes in health. (It doesn't help that sites such as Mayo Clinic and Family Doctor -- sponsored by the American Academy of Family Physicians -- suggest that heat exhaustion presupposes elevated body temperature, while the symptoms themselves do not. At least the University of Maryland Medical Center site admits that these symptoms can be related to insufficient electrolyte replenishment. For more on the electrolyte issue, look up "hyponatremia".

Disclaimer: I am not a doctor or a medical professional. My observations are based on my own experiences and the anecdotal reports of others.

Dehydration and insufficient electrolyte replenishment can each lead to muscle cramps, and/or a drop in blood pressure as the body is depleted of the salts it needs to signal the muscles to contract and relax correctly (remember, the heart is a muscle!). In addition, a drop in body fluid volume can make the heart less effective at pumping oxygen through the body, and our bodies less effective at maintaining a steady core temperature -- so we might experience dizziness, shortness of breath, or feverishness as well. Now, considering that for many of us, these are symptoms we may experience when hypoglycemic, we -- and our caregivers -- need to know what might be causing our disorientation so it can be treated correctly.

More serious in general is the issue of heat stroke. In this case, the body temperature has definitely risen to feverish levels, and either because of lack of fluid or lack of electrolytes, it has stopped sweating. Since sweating is one of the major methods our bodies have of cooling themselves, this constitutes a medical emergency and requires immediate medical attention.

For myself, I have certain levels of fluids I expect to -- and want to -- consume while outdoors during hot weather (for what it's worth, 1/2 liter per hour if I'm just out-and-about, 1 to 1.25 liters per hour if I'm exercising or deliberately expending energy, the fluids split equally between water and electrolyte-replacement drinks). Even so, I may find that after a particularly strenuous ride or hike, or when the sun beats down more warmly than the weather report suggests, I may find myself a bit dizzy. It's been a bit trial-and-error, but what I measure during these episodes is that my blood pressure has dropped, and what I need to do is to replace fluids and electrolytes.

If, during these episodes, my blood glucose levels are doing anything "diabetic", they'll more likely be high than low -- a result of dehydration-based or low-electrolyte-based stress. While those high blood glucose levels (usually under 150 -- but remember, I don't like to see numbers over 120) bother me, my Type 2 care regimen doesn't give me anything other than time and water to bring them down -- and if I'm depleted enough to be dizzy, the diabetes becomes a secondary concern.

Obviously, I'm going to seek out as cool a place as I can find and rest (except for grabbing more electrolyte-replacement fluids and giving my kidneys a workout) until I find my blood pressure, and my sense of equilibrium, returning to normal.

I've never tried taking my body temperature during one of those "dizzy" episodes, since they also happen in winter when I'm riding hard in the cold and wind, but based on some of the home medical sites, I think I'm going to start adding that to my assessment. And I'm going to suggest that if you don't have one already, investing $50-$70 for an automatic blood pressure meter with a 50-measurement history and learning your normal blood pressure ranges could be a prudent measure in our understanding of how your body reacts to heat and exercise, and in making sure you get the correct treatment for the correct medical issue, in the correct order.

We -- like all other populations at increased risk for heat-related illness -- need to keep cool, keep hydrated, keep our electrolytes balanced, and provide a way for first-responders and our medical staff to know what our norms are. Knowing how we react to different levels of hydration stress and thermal stress is another tool in keeping us alive and healthy.