It is hardly a secret that exercise is a fundamental component of living a healthy lifestyle. Along with maintaining a good diet, getting enough sleep, and staying hydrated, exercising regularly can have tremendous benefits for all aspects of physical health and longevity. Whether it’s a brisk jog in the morning, a competitive sport like soccer or football, or lifting heavy weights in the gym, your body will thank you for staying active.

However, as with many things in life, the situation is, unfortunately, a little bit more complex for people with diabetes. For diabetics, exercise can and should still be incorporated as part of a larger diabetes management plan. It may just take a little bit more consideration in order to counter the spike in blood sugar that can sometimes accompany a workout session and leave diabetic athletes confused and frustrated.

To be clear, not all physical activity will cause a spike in blood sugar for all diabetic people. In fact, it can often have the opposite impact. Many diabetics may already be aware that physical exercise can be useful in lowering blood sugar since it increases the body’s energy demands and thereby depletes the circulating glucose levels to meet those demands. But this doesn’t tell the full story, since exercise can have the complete opposite effect of spiking blood sugar during and after a session. In the rest of this article, we will explain which types of exercise are most likely to increase blood sugar, and what you can do to help manage these effects while staying active.

Why does exercise cause blood sugar to sometimes spike?

Your Body’s Perspective

At first, a rise in blood sugar caused by exercise may seem unintuitive. After all, glucose is one of the primary ways the body fuels its various activities, and one would expect that being more active would burn up glucose stores rather than increase them. However, there is a sound physiological explanation for why some forms of exercise actually raise blood glucose levels.

Exercise is very energy intensive, but some forms are more intense and require larger bursts of energy in shorter periods of time. The human body has developed mechanisms to finely control the amounts of glucose circulating in the body in order to meet the current levels of demand based on whatever the body happens to be doing at that time, or what the body predicts it will be doing in the near future. In a perfect situation, the body strikes a precise match and releases the exact amount of glucose required to meet the demands of the moment, leading to a steady or slightly reduced level of blood glucose after exercise. Sometimes, however, the body gets the balance wrong and releases more glucose than is required. When this happens, blood glucose levels elevate temporarily, before typically returning to a baseline.

There are various mechanisms that the body uses to coordinate increases in blood glucose to meet the demands of exercise. Understanding these mechanisms can help better understand how to mitigate their effects. We detail these mechanisms below:


One chemical messenger used by the body is adrenaline, commonly known as the “fight or flight” chemical. Adrenaline, which is a stress hormone, indicates to your body that a stressful event is occurring to which your body should be prepared to react. Part of the adrenaline resp