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In the never-ending pursuit of homeostasis, our bodies work to regulate countless processes. Paramount among these is body temperature. Even a body temperature shift of a few degrees can be catastrophic for our health; enzymes slow down, electrolytes get too low, and hormones don’t work as well . Unfortunately, temperature regulation in the body is disrupted when metabolic function is disrupted and glucose levels are elevated.
The heat we produce in our bodies is the result of countless chemical reactions occurring in every cell. This heat production is generally matched with an equal heat dissipation, ensuring body temperature stays in a narrow range. Human bodies have a unique advantage over other terrestrial mammals—our naked skin is a superior thermoregulator, allowing us greater heat dissipation than other animals. Interestingly, glucose, a seemingly innocent nutrient, gets in the way.
Of course, the most obvious instance is elevated glucose is diabetes, where we see this phenomenon quite readily. Whether it’s type 1 or type 2, people with diabetes have a harder time keeping body temperature in control . This phenomenon is particularly evident with exercise in diabetes. During exercise, the increased physical exertion results in greater heat production, which is generally accounted for by a comparable increase in heat loss. However, the “heat loss” side of the equation is compromised with diabetes. Indeed, during a bout of exercise, someone with diabetes will keep up to 54% more heat than a comparably sized person without diabetes [2, 3]!
Importantly, the problem of glucose-induced changes in body temperature isn’t simply a consequence of chronically elevated glucose levels. Even in healthy people without diabetes, acute spikes in glucose, either by glucose infusion or excessive carbohydrate consumption, body temperature climbs [4, 5].
The blood vessel is at the core of the problem with poor body temperature control and high glucose levels. To effectively remove heat from the body, we need a hemodynamic shift that arises from coordinated changes in the size of blood vessels throughout the body—blood vessels in the core of the body constrict, and those at the periphery (i.e., skin) dilate. These changes allow the body to transfer the heat from deep within the body to the skin and eventually to the air around the body.
Beyond the discomfort of being hot and sweaty, having a high body temperature can compromise optimal function, including one of the most important things we do for our health: sleep. Increased body temperature, especially through reduced heat dissipation, is one of the most common causes of “frequent waking” insomnia . Thus, it’s little surprise that consuming a high-carbohydrate load before bed, and the commensurate blood glucose and body temperature spike, results in more frequent waking and worse sleep .
So, if you’re “feeling the heat,” it might be time to check your glucose levels.
- Ahmed, A.; Sadaniantz, A., Metabolic and electrolyte abnormalities during heat exhaustion. Postgrad Med J 1996, 72, (850), 505-6.
- Kenny, G. P.; Sigal, R. J.; McGinn, R., Body temperature regulation in diabetes. Temperature (Austin) 2016, 3, (1), 119-45.
- Kenny, G. P.; Stapleton, J. M.; Yardley, J. E.; Boulay, P.; Sigal, R. J., Older adults with type 2 diabetes store more heat during exercise. Med Sci Sports Exerc 2013, 45, (10), 1906-14.
- Green, J. H.; Macdonald, I. A., The influence of intravenous glucose on body temperature. Q J Exp Physiol 1981, 66, (4), 465-73.
- Welle, S.; Campbell, R. G., Stimulation of thermogenesis by carbohydrate overfeeding. Evidence against sympathetic nervous system mediation. The Journal of clinical investigation 1983, 71, (4), 916-25.
- Lack, L. C.; Gradisar, M.; Van Someren, E. J.; Wright, H. R.; Lushington, K., The relationship between insomnia and body temperatures. Sleep Med Rev 2008, 12, (4), 307-17.
- Jalilolghadr, S.; Afaghi, A.; O’Connor, H.; Chow, C. M., Effect of low and high glycaemic index drink on sleep pattern in children. J Pak Med Assoc 2011, 61, (6), 533-6.