We all know that physical activity is good for us. It can help keep our weight under control and even keep us from developing diabetes. But what happens to someone whose blood sugar is already elevated? Can exercise really help bring glucose levels down, or at that point is the person going to have to rely on medication to do the job?

The short answer is yes, exercise not only can help prevent obesity and diabetes, but can play an important role in bringing blood sugar back down after it’s elevated. Researchers at the University of Newcastle in Australia found that when participants with prediabetes combined resistance training, aerobic exercise, and dietary changes, they were able to lose weight while improving their fasting glucose levels and their glucose tolerance. Other studies have shown that sticking to an exercise program for eight weeks can have the same effect on blood sugar as medication.

Exercise and blood sugar

So what’s going on inside the body during exercise that could cause blood sugar to go down? There are at least three mechanisms that cause this to happen.

  • Exercise increases insulin sensitivity.Insulin is a natural hormone that helps our bodies process sugar as fuel. In people with diabetes, the body’s ability to use insulin properly has become impaired. Sugar that cannot be burned off as energy because of this insulin dysfunction gathers and circulates in the bloodstream, causing damage to organs. But when we exercise, our insulin sensitivity increases, re-granting us access to circulating blood sugar that we can burn as energy. Taking that sugar out of the bloodstream, of course, results in a lower blood-sugar level.
  • Exercise burns sugar.Quite simply, working out requires energy, and this sudden demand means that the body will start looking for glucose throughout the organs. Sugar is stored in the liver and in the muscles. During your workout, this sugar gets burned up as energy. Your body was happy storing that glucose in your muscles and liver, so now it wants to replace it. It replenishes these stores by drawing on glucose that has been circulating in the bloodstream, bringing down your level of blood sugar.
  • Muscles under strain use glucose.This is why resistance training is an important form of exercise for diabetes. While there’s no doubt that aerobic, or cardiovascular, exercise is important for maintaining a healthy weight and keeping blood sugar in check, you should also fit in two or three strength-training sessions every week. Having more muscle gives you greater blood-sugar control because your muscles take sugar out of the bloodstream and use it for fuel both during and after your workout.

Can exercise raise glucose levels?

There is one anomaly when it comes to exercise and glucose levels. Even though exercise is unquestionably good for people with diabetes, it’s possible for some types of movement to actually cause a temporary spike in blood glucose levels. The science on why this happens is still relatively young, but it would appear that certain forms of physical activity that call for short bursts of high-intensity effort…including sprinting, intense aerobic activity such as spinning, and weightlifting…trigger the release of glucose-raising hormones that increase blood-glucose levels to compensate for the sugar you’re taking out of the bloodstream. When you’re working very hard, your body responds to this sudden increased energy demand by converting lactic acid into glucose for your muscles to use as fuel. And during competitive moments requiring bursts of energy, you may even enter a “fight or flight” state during which adrenaline causes the liver to release glucose to help you power through.

However, that doesn’t mean that these forms of exercise are generally bad for you, or even bad for your blood sugar. Even though they may cause a temporary spike in glucose levels, resistance training is important for glucose management because it increases insulin sensitivity. Looking at the overall picture, you’ll do much better at keeping blood sugar in check if you’re regularly participating in physical activities that you enjoy. An occasional glucose spike when the pickleball game heats up is far better than sitting on the couch.

The effects of these glucose spikes may be mitigated by combining those exercises that entail sudden bursts of energy with those that take place over a more prolonged period and at a lower intensity. For example, you could perform your weightlifting exercises during breaks from a long walk on a treadmill, or just sandwich your racquetball game between long warmup and cooldown laps around a track. You can also lessen the intensity of glucose spikes by avoiding exercising on an empty stomach or early in the morning, the period of the day when the body’s insulin is least available and when the liver releases stored glucose into the bloodstream.

Choosing a routine

When it comes to selecting the movements and schedule for exercising to lower blood sugar, there’s no one-size-fits-all plan. Each person must arrive at a set of activities they enjoy and have access to, and find the time or times that work best for their lifestyle. But broadly speaking, try to incorporate the following:

  • Some form of moderate-to-high-intensity aerobic exercise three to five times per week for at least 30 minutes per session
  • Two or more resistance (strength) training exercises per week
  • Increased “everyday” physical activity such as taking the stairs instead of the elevator, walking across the parking lot, standing instead of sitting, taking an evening stroll, and so on. Frequent low-level activity is better than spending most of the day sedentary and then squeezing in half an hour of exercise

Overall, some exercise is better than none, and the more often the better. Also, don’t let your routine stagnate. If it becomes too easy, or boring, changing it up, and stepping it up, is not only more exciting but it’s good for your muscle and your bloodstream, too. 

Related Articles