Many are aware of climate change and its effects on our planet, but research suggests that it is rewriting the rules of metabolic health as well.

Diabetes is a metabolic, autoimmune and chronic disease where the pancreas produces little to no insulin, or the body cannot respond to insulin correctly, resulting in high glucose levels in the bloodstream. Here’s how it works: your bloodstream carries sugar from the food you eat to different parts of the body where it can enter cells and be used for energy. When large amounts of glucose enter the bloodstream (i.e. when you eat), a gland called the pancreas releases the hormone insulin. This hormone allows the sugar to be able to leave the bloodstream and enter cells for energy production.

Type One diabetes occurs when the body mistakes beta cells (insulin producers) in the pancreas as foreign invaders and destroys them, leaving glucose levels too high in the bloodstream. In Type Two diabetes, cells do not respond to insulin, so sugar remains in the bloodstream and accumulates. The pancreas then sends excessive insulin to compensate. This is known as  hyperinsulinemia. Over time, the beta cells cannot keep up with the demand and become damaged.

The Biology of Heat

So what does climate change have to do with any of this? There are many ways that heat impacts the body and results in an increase of glucose levels, something diabetics must be perpetually conscious of in order to treat and avoid. One way that higher temperatures can cause glucose spikes is in their effects on brown fat. Brown fat in our body is responsible for keeping us warm. It is packed with mitochondria that rapidly oxidize glucose in the bloodstream in order to gain energy to regulate our bodies’ temperature. The main trigger for this process is cold exposure. In hotter temperatures, the sympathetic nervous system does not stimulate the mitochondria to “waste” energy on heat, and the extra glucose remains in the bloodstream. The increasing heat in our atmosphere means that our brown fat will not be activated as often, and blood sugar levels will rise. Another way heat causes high glucose levels is through “heat stress.” Intense heat acts as a stressor to the body, increasing cortisol levels. When the body is stressed, the liver releases stored glucose, raising blood sugar. Furthermore, heat causes dehydration, which also provokes more sugar in the bloodstream. High glucose levels are extremely dangerous for diabetics, as their body cannot naturally fix these problems caused by the external outcomes of climate change. Prolonged high blood sugar can lead to serious complications such as heart disease, kidney failure, blindness, nerve damage, and foot ulcers.

A Growing Risk

It sounds bizarre, but climate change’s influence on blood sugar can potentially cause diabetes as well. Type Two diabetes is not innate, unlike Type One, and occurs when extended periods of high blood sugar damage the pancreas by forcing it to overwork. The way heat controls glucose from brown fat, to heat stress, etc., affects nondiabetics just as severely, and the longer it transpires, the more people are at risk of developing type two diabetes. According to the National Library of Medicine, a one-degree celsius increase in temperature could cause over 100,000 new diabetic cases in the U.S. alone.

The Danger of The “Low”

Climate change, in addition, can also lead to low blood sugar levels. Heat can cause blood vessels to dilate, which can enhance insulin absorption. This means when diabetics inject insulin, the body is more sensitive to it and the insulin takes too much glucose out of the bloodstream, not leaving enough to provide energy. This is far more dangerous than high glucose with symptoms such as shaking, weakness, chills, extreme hunger, dizziness, confusion, anxiety, numbness, tingling, blurred or double vision, slurred speech, seizures, loss of consciousness, nightmares, and also death. In Brisbane, hospitalizations for diabetes increased by 37% during high intensity heatwave days. And another systematic review reported an 18% increase in diabetes mortality associated with heatwave exposure.

Beyond the Body

Climate change can also be detrimental to diabetic equipment as well. Glucometers and test strips cannot be exposed to extreme heat or humidity, or else they may become damaged and give false readings. This can be incredibly dangerous for diabetics as attempts to treat these false readings could cause a change in glucose that could be perilous  for the body.

Furthermore, the insulin diabetics inject to regulate blood sugar must be stored in a cool place for it to work effectively, for example, a refrigerator. Once you impale a new vial with a syringe, you have only 28 days until the insulin is completely unusable. This not only means that global warming will harm insulin and its ability to work, but natural disasters associated with climate change—hurricanes, floods, etc.—could leave many diabetics without a power source to cool their medicine, and make necessary medication inaccessible.

As the Earth heats, more power will have to be used to keep insulin cool, causing more greenhouse gases to be emitted, leading to even higher temperatures. This is a positive feedback loop, meaning the outcome of the process reinforces/exacerbates the process to build momentum. More power being needed to cool insulin also creates a financial burden for diabetics. Not only is the global temperature rising, but the cost to stay healthy is as well. 

The Path Forward

Climate’s effect on diabetics is a widely unknown and un-talked-about subject. Everyone must work to educate others to ensure non-diabetics are aware of their increasing risks, and people  with diabetes can prepare to face glucose fluctuation and have plans to keep their essential equipment safe.