prediabetes and physical exercise

Prediabetes and Physical Exercise: What’s Best for Diabetes Prevention?

When it comes to prediabetes, diet is often the first thing most people think of changing. But, it’s not the only action you can take to reduce your risk of diabetes. So, what about exercise? Does exercise help prediabetes?

Yes. Absolutely. And in this article, we’ll take a look at the relationship between prediabetes and physical exercise, including:

  • What kind of exercise is good for prediabetes?
  • How does exercise help prediabetes?
  • Is walking or running good for prediabetes?
  • What’s the best time to exercise for prediabetes?

I know starting a new exercise habit takes a lot of effort. The last thing you want to do is waste time on bad information. So, within each of the following sections, you’ll find research to back it up. As a Registered Dietitian and Clinical Exercise Physiologist, I always strive to provide evidence-based health guidance that’s actionable and applicable to your daily life. 

Now, let’s get started.

How Does Exercise Help Prediabetes?

Eating well and exercising are two pillars of prevention that are often recommended ad nauseum by health professionals. But, what is it about exercise that’s good for prediabetes? 

Numerous studies have established that lifestyle changes are more effective than medication alone for preventing diabetes. And, an important element of lifestyle change is including regular physical activity. 

One reason exercise is helpful for prediabetes is that it promotes weight loss. But, exercise can be beneficial, even without the occurrence of weight loss.

That’s because exercise can:

  1. Improve your body’s ability to utilize blood sugar
  2. Increases the demand for glucose
  3. Improve insulin sensitivity
  4. Build muscle (which helps improve insulin sensitivity and glucose uptake)

As you exercise, you increase your muscles need for fuel. An easy and quick source of fuel is the glucose in your blood. So, when you exercise on a regular basis, it helps lower your average blood sugar.

Another benefit is the effect exercise has on insulin sensitivity. Insulin is the hormone released from your pancreas after eating. It’s like a key  that unlocks your muscle cells, and allows glucose (sugar) to enter.

During the early stages of type 2 diabetes (prediabetes), the body starts to become insulin resistant. That means it begins to ignore insulin. It’s like insulin is knocking on the door but your body can’t hear it. So instead of sugar entering the cells, it begins to back up into your bloodstream, causing an increase in your fasting blood sugar or A1C. This is what’s thought to be happening when prediabetes is diagnosed.

But research shows that exercise can help increase your sensitivity to insulin, hence allowing it to more effectively do its job, preventing sugar from backing up, causing increased blood sugar levels. 

What Kind of Exercise is Good for Prediabetes?

what kind of exercise is good for prediabetes and diabetes prevention?

We know that exercise is good for prediabetes, but what type of exercises should you be doing? And, how much?

Although researchers have attempted to compare different types of exercise to find which is the most effective, there is limited data to suggest one specific modality is best.

Instead, the American College of Sports Medicine (ACSM) recommends a combination of both aerobic and resistance training, as well as stretching.

Recommendations are largely the same as they are for type 2 diabetes:

  • At least 150 minutes (2 ½ hours) per week of moderate intensity aerobic exercise
  • 2-3 days of strength training with 24 hours rest in between
  • 2-3 days of stretching, holding each stretch for 30-60 seconds

From here, you can use these basic guidelines to include exercises that best fit your interests and abilities.

Let’s take a look at some different aerobic and strength training options.

Aerobic Exercise for Prediabetes

aerobic exercise for prediabetes

Aerobic exercise, or cardio, is a rhythmic activity that incorporates large muscle groups and increases heart rate, breathing and blood flow. Examples include bicycling, walking, running, hiking, swimming, and dancing. 

Studies have long proven the benefits of aerobic activity for reversing and preventing cardiovascular disease. But, exercise benefits are simultaneously found for diabetes and prediabetes. 

Amongst groups of prediabetic patients who participated in aerobic training 3-4 times per week, they found improvements in a number of diabetes related risk factors:

  • a significant reduction in BMI
  • a decrease in fasting blood glucose levels
  • significant improvements in 2 hour plasma glucose levels 
  • a decrease in HbA1c levels

The good news is that aerobic exercise can include a lot of different activities, and it doesn’t have to be super intense to be beneficial. What’s more important is the combination of intensity and duration.

The ACSM recommends:

  • 150 minutes per week of moderate intensity aerobic exercise
  • 75 minutes per week of vigorous intensity aerobic exercise

However, there are no rules on how to split this up. For example, to hit the goal of 150 minutes per week, you can do 30 minutes per day for 5 days a week. And, that 30 minutes each day can be split up into three 10 minute bursts spread throughout the day. 

What’s the Difference Between Moderate and Vigorous Intensity Aerobic Exercise? 

Exercise intensity is estimated based on a percentage of your maximum heart rate (HR max). In a lab setting, it’s possible to measure your maximum threshold, but for most of us that’s not practical.

So, instead we can estimate our HR max using a simple calculation:

220 – Your Age in years = HR Max. 

This isn’t a perfect estimation, but it will give you a rough estimate of HR max. If you have a fitness watch like a Garmin or Apple Watch though, it may give you more accurate estimation. 

Moderate Intensity Aerobic Exercise is defined as 65-75% of your max HR. If you can comfortably talk, but not sing, you’re likely doing moderate intensity exercise. This would be 3-4 out of 10 in terms of exertion. 

Vigorous Intensity Aerobic Exercise is defined as 76-96% of your max HR. You shouldn’t be able to say more than a few words without gasping for air when exercising at a vigorous intensity. This should be a 5-7 out of 10 in terms of exertion level.

Here’s a table with estimated HR Max by age. Keep in mind, this is provided solely for educational purposes. Before using these values, you should consult with a healthcare professional to determine what kind of exercise is best for you. 

AgeEstimated HR MaxModerate Intensity HR RangeVigorous Intensity HR Range
25195127 – 146148 – 187
30190124 – 143144 – 182
35185120 – 139141 – 178
40180117 – 135137 – 173
45175114 – 131133 – 168
50170111 – 128129 – 163
55165107 – 124125 – 158
60160104 – 120122 – 154
65155101 – 116118 – 149
7015098 – 113114 – 144
7514594 – 109110 – 139

Here’s a nice infographic from ACSM on exercise intensity.

Research suggests that a combo of aerobic and resistance training can lead to greater benefits in glycemic control, than either form of training can provide alone. But, if you only have time to start with one, research suggests that aerobic training alone is more beneficial than strength training alone.

Here are a couple ideas to get you started with aerobic training for prediabetes. 

Is Running Good for Prediabetes?

is running good for prediabetes?

Typically, running is considered a high-intensity aerobic exercise, and it can be excellent for helping to reverse prediabetes. 

One study found that runners had a 28% lower risk of developing type 2 diabetes compared to non runners when tracked over a 6.5 year period.

And fortunately, you don’t need to be a sprinter to experience the benefits of running. Although people with prediabetes who engaged in sprint training had a higher perception of enjoyment, and more fat loss than those in a moderate intensity running group, they both saw similar improvements in hemoglobin A1C, and fasting glucose. So, you can get similar benefits from high intensity sprinting as you can longer duration moderate intensity running.  

However, if you’re new to running, it’s important to start gradually to avoid injury. This is especially true for sprinting. And, if you have any heart condition, consult with your healthcare provider before starting a running routine. 

Is Walking Good for Prediabetes?

is walking good for prediabetes?

After all this talk about running, and sprinting, you’ll be happy to know that even walking can offer significant benefits for prediabetes. A study comparing the health benefits of running and walking found no significantly different risk reductions for diabetes or high blood pressure when comparing running vs walking.

One interesting study even found lower rates of prediabetes for people living in more walkable city areas vs those who lived in non-walkable regions. Another study found people who lived in walkable neighborhoods had 67% lower risk of having prediabetes vs those living in car-dependent neighborhoods.

This makes a case for:

  • Building more pedestrian friendly neighborhoods
  • Choosing to live in places that are walking distance to stores and parks

However, walkable neighborhoods do tend to have a higher cost of living due to increased home costs. 

Resistance Exercise or Weight Training for Prediabetes

There are many different types of resistance training, but they all involve moving your muscles against some force of resistance, whether it’s:

  • Weight training 
  • Body weight training
  • Using elastic resistance bands

By stressing your muscles against resistance, your body is stimulated to create more muscle. And, muscle is a highly metabolically active tissue, meaning it requires a lot of energy, including glucose. Your muscles actually hold some glucose inside of them as a quick energy source. 

So, with resistance or strength training, your body utilizes the sugar (aka glucose) in your blood. And, as you build more muscle, it’s like creating more furnaces to be able to burn more sugar in your system. 

Essentially, muscle mass helps your body better utilize blood sugar. 

Studies support this, showing a threefold greater reduction in A1C in diabetic patients who participated in resistance training. They also had improved glucose and insulin responses. 

With aging we typically see a decline in muscle mass. Simultaneously, we see the risk for diabetes increase with age. This underscores the importance of resistance training for muscle retention given the role muscle plays in glucose metabolism, and benefits it provides for diabetes prevention. 

For the most benefit, aim to get:

  • two or more resistance training sessions per week
  • 2-4 sets for each strength building exercise you do
  • 8-10 repetitions for each set

Check out my article on creating a minimalist home gym for some gear tips.

Does Hiking Help With Prediabetes? 

does hiking help prediabetes?

If walking, and weight training are good for prediabetes, logic would conclude that hiking and backpacking are also good for prediabetes, since it combines moderate intensity aerobic exercise with carrying weight on your back. And, as it turns out, research does support this. 

In a study that compared sedentary people to those who hiked downhill 3-5 times per week for two months, the downhill hikers had: 

  • Reduced insulin resistance
  • Decreased fasting glucose
  • Improved glucose tolerance

When comparing uphill hiking to downhill hiking, research suggests better results for prediabetes with uphill hiking, but when researchers adjusted for estimated energy expenditure both had similar benefits. In reality though, hiking involves both uphills and downhills, so moral of the story – all hiking is good for you. As a PCT hiking veteran, this is music to my ears. 

Hiking aside, research even suggests that simply spending time outside can benefit blood sugar control. 

What About High Intensity Interval Training? 

High Intensity Interval Training, or HIIT has been a popular exercise trend over the past several years. And there’s evidence that shows HIIT can improve:

  • Blood pressure
  • Insulin sensitivity
  • Cholesterol levels

If you’re just getting started with exercise training, it’s not advisable to immediately jump into HIIT training, due to an increased risk for injury. But, it can be beneficial to layer in as you become more consistent and comfortable with your exercise and physical activity.

A recent trial concluded that HIIT could be beneficial for decreasing fasting blood glucose, and A1C in people with prediabetes, and found that high volume HIIT could be more beneficial for glycemic control than low volume HIIT.

One of the most interesting things about HIIT is that research shows better adherence to it than moderate intensity training. This is likely because one of the primary challenges people struggle with is making time to exercise. With HIIT, the focus is on exercising for less time, but at a higher intensity. 

Despite all these benefits, it’s advisable to speak with your healthcare provider before beginning a high intensity exercise routine. 

Here’s a helpful handout from ACSM on High Intensity Interval Training. 

Does Yoga Help with Prediabetes? 

yoga for prediabetes

Given the popularity and appeal of yoga, you may be wondering – can yoga help reverse prediabetes?

Yoga does not fit cleanly into the descriptions of aerobic or resistance training provided above, but it does include elements of both, while also including stretching and flexibility. Depending on the rate of yoga you’re doing, it can certainly be aerobic, and it does involve resistance training using your own body weight.

Although there’s limited research on Yoga in relation to prediabetes, one study on 100 prediabetic participants found yoga to have a favorable effect on fasting glucose and A1C. A separate study found improvements in BMI, waist circumference, blood pressure, and fasting glucose, but no improvements in A1C. 

As you can see, the evidence supporting yoga for prediabetes is somewhat murky and very limited. But, if it’s an activity you enjoy and can do consistently, keep it up. As long as it’s helping you hit the aerobic activity and resistance training guidelines, it will most likely reduce your risk of diabetes. 

What is the Best Time to Exercise for Prediabetes?

There have been a multitude of studies on exercise timing for sports performance, but fewer studies on exercise timing for diabetes prevention. 

In general, the most benefit can be found from spreading small bouts of exercise throughout the day vs sitting sedentary. That means getting up and taking walking breaks throughout your working day. 

But what about morning vs evening? Is there a better time to exercise for prediabetes? After all, most of us only have a limited amount of time to exercise, so where are we likely to get the most benefits for prediabetes? 

Research is still somewhat limited on the subject, but there is some evidence to suggest evening exercise could be more beneficial for glycemic control. 

One short term study on overweight and obese men following a high fat diet found afternoon endurance exercise improved 24 hour glucose levels and triglycerides more so than exercising in the morning. Cardiac benefits however, were similar for both morning and evening groups.

For those with type 2 diabetes, a meta review further suggests syncing exercise timing with meal timing and your circadian clock, by exercising after dinner. This is because the evening is the time of the day where people tend to have the worst glucose control. So, by exercising post dinner, you can improve your overnight blood sugar control as well.

If you’re looking for the best exercise timing for prediabetes, this article recommends exercising after each meal because of the immediate glucose-lowering effects which occur from muscle contraction. In fact, walking for 15 minutes after each meal is associated with better post-dinner glycemic levels than doing just one 45-minute walking session earlier in the day. 

But, keep in mind, your exercise timing does not need to be perfect. And, your exercise program does not need to be perfect. Most importantly, it needs to be conducive to creating a habit that you can commit to and perform consistently. That’s where the most benefit comes from. 

So, you should exercise at whatever time of the day best fits your schedule.

Exercising at any time of day is better than not exercising at all.

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