Strength Training May Help Prevent Diabetes

Type 2 diabetes, one of the most common metabolic disorders, is on the rise. Approximately 589 million adults worldwide live with this condition, and while type 2 diabetes is preventable, experts predict that number is on the rise.

Diabetes can be a gateway to other diseases, including heart disease, stroke, dementia, high blood pressure and atherosclerosis (narrowing of the blood vessels). It can also cause you to lose your sight, and as blood vessels narrow and circulation to extremities decreases, it can even result in amputation. 

Type 2 diabetes (T2D) is an intersection of genetics and lifestyle behaviors. And while there’s not much we can do about our genes, there’s a lot we can do about our health habits. For example, exercise influences blood glucose (or sugar) levels, and blood glucose levels play a large role in T2D. While experts have long recommended cardio exercise as a smart choice to help prevent diabetes, it’s also possible that strength training could be beneficial as well.

That’s what researchers in Hong Kong wanted to explore. They published their findings in February in BMC Medicine. Let’s break down what they discovered. 

How Was This Study Conducted?

This study used data from the UK Biobank, a long-term, ongoing medical study that includes over 500,000 UK adults. For this study, information was pulled on 141,848 white British adults with valid genetic data available. Participants had an average age of 57, and about 55% were female. 

These participants had data on grip strength, a test often used in research because it’s simple and has been shown to correlate with upper-body strength. Using age and sex-specific cut-off points for relative grip strength, participants were categorized into one of three groups based on their grip strength results: high, medium or low.  

In addition, body composition—the ratio of fat-to-lean tissue—was measured using bioelectrical impedance. Each participant’s genetic susceptibility to T2D was calculated using what’s known as a PRS value, which is estimated based on 138 known genetic variants for T2D. In other words, their genes were assessed for variations that have been shown to predispose people to T2D.

Demographics that were also adjusted for during statistical analyses included sex, socio-economic status, employment status, tobacco use, alcohol use, red meat intake, fish intake and physical activity. Participants were followed for more than seven years, during which time 4,743 new cases of T2D were identified. 

What Did This Study Show?

Several findings surfaced after statistical analyses were run. 

• Compared with low muscle strength, high muscle strength was associated with a 44% lower relative risk of developing T2D, even after taking into account T2D genetic risk as well as other risk factors. 
• Researchers also observed evidence of an interaction between muscle strength and genetic susceptibility to T2D. This suggests that muscle strength may play a role in modifying the impact of genetic risk on T2D onset.
• Individuals with a high genetic risk for T2D who also had high muscle strength may have a lower absolute risk of T2D compared to those with low or medium genetic risk. 

Overall, researchers concluded that, according to this study, higher muscle strength was associated with a lower relative risk of developing T2D, regardless of genetic risk. 

There are a few limitations to this study. First, despite Black adults being at higher risk for T2D, this study used white adults from the UK. As a result, it’s unknown if these results also apply to other populations in other areas of the world. Also, due to the observational nature of this study, it can only suggest that there is a relationship between factors, not that one causes the other. 

How Does This Apply to Real Life?

Researchers note that while they can’t fully explain why having more muscle is linked to a decrease in T2D, evidence indicates that a loss of muscle mass and muscle strength can potentially lead to a decreased surface area of glucose transport and the potential worsening of insulin resistance. 

But why? The answer lies in the relationship between muscle, glucose and insulin.

“Muscle is metabolically active and uses glucose, so more muscle means using more glucose from the blood,” explains Sarah Pflugradt, Ph.D., RDN, CSCS, performance nutritionist and owner of Sarah Pflugradt Nutrition. “There is some evidence to suggest that increased muscle strength increases insulin sensitivity, which helps lower the risk of high blood sugar, a marker of pre-diabetes and type 2 diabetes. This research confirms what many other studies have found—that increased muscle mass and strength reduce the risk of type 2 diabetes.”

Having stronger muscles has other benefits, too, including having the strength to perform everyday activities with more ease and reducing the risk of falls and injuries. Healthy posture and strong muscles go hand-in-hand. Poor posture can affect many things, including back and neck pain, and may lead to poor digestion, depression and anxiety. Strengthening your muscles may even add years to your life. 

Ready to get going? Here are a few tips to get you started on a journey toward healthy, strong muscles. 

• Start where you’re at. Avoid comparing yourself to others or to your old self, if you were more fit in the past. Begin where you’re currently at and progressively increase intensity and duration over time. 
• Individualize your approach. If you’re using weights—free weights or machines—start with an amount of weight that allows you to do up to 12 repetitions, with the last rep being difficult to do. Note that the amount of weight will vary for different body parts. These principles also apply to using resistance bands or similar modalities. 
• You don’t have to join a gym (unless you want to). This is a myth many people fall for. There are so many options available to us nowadays that the gym just isn’t as necessary as it once was. Whether you look to apps or YouTube, you can easily find a routine to follow. And you don’t need to spend a ton on equipment. Your body is a gym unto itself. 
• Mix it up. Your body has an amazing ability to adapt. This means that doing the same routine for months will stall your progress. Switch your exercises up either workout-to-workout or every few weeks. This can also be accomplished by progressively increasing the weight or resistance and doing more than one set of each exercise.
• Include all muscle groups. People tend to be more concerned about the muscles they can see in the mirror. But this leaves over half of your body out. The back of your body matters just as much as the front, as do the deeper, more internal muscles, many of which help stabilize your spine. 

It’s also good to remember that rest is as important as your workouts. If you’re working your muscles beyond what they’re typically used to, you’re actually breaking down muscle tissue—that’s why you may feel sore for the next couple of days. After being torn down, your muscles rebuild and add a little extra. This is how they grow and get stronger. But to do so, they need recovery and rest. This doesn’t mean you have to avoid physical activity, but keep it light on your off days.

The Bottom Line

This study suggests that, compared with low muscle strength, having higher muscle strength may reduce the risk of type 2 diabetes by 44%, including for those with a high genetic susceptibility for the condition. If you don’t currently engage in weekly strength training, consider adding it to your routine and getting help with it if needed—and remember to check in with your healthcare practitioner to be sure it’s okay for you. 

In addition to strength training, include cardio exercise and stretching several times a week. A healthy, balanced eating pattern, like the Mediterranean diet, has been linked with a lower risk of type 2 diabetes, as well. And be sure to get plenty of quality sleep, manage your stressors and spend time with loved ones to ensure a well-rounded, whole-health approach to diabetes prevention.