The Effect of Aging on Your Blood Glucose Levels

Regardless of how old you are, your blood glucose levels will rise and fall through the day. It’s fascinating to see this happen in real-time, which you can now do with a continuous glucose monitor! Just how much your levels rise and fall through the day will usually depend on what you eat and how much energy your body burns. And as you age, you’ll likely experience some changes in your blood glucose levels too. Some older people may see more frequent spikes, putting them at risk of developing diabetes. In fact, according to the CDC, about 29.2% of people older than 65 have diabetes. 

Wondering why this happens? Your body’s ability to produce insulin naturally decreases over time, which may make it more difficult for it to process sugar effectively. This often leads to a rise in blood glucose levels, which in turn increases your risk of developing things like heart disease and stroke. Remember that aging changes the way your body metabolizes glucose, which is a contributing factor here. Glucose levels also fluctuate due to physiological factors that affect how your body handles carbohydrates, fats, and proteins. 

Understanding your health history and risk for developing diabetes can be challenging. But it’s always better to be well-informed, especially about what’s going on inside your body. So let’s learn a little more about how aging affects your blood glucose levels.

How Your Body Handles Glucose as You Age 

Your body goes through many changes as you age. While you may be expecting some of these like an expanding waistline or gray hair, you may not see others (like higher blood glucose levels) coming. And as we mentioned earlier, it’s also common to experience changes in glucose metabolism as you get older.

Studies have found that as people age, elevated glucose and insulin levels are more prevalent when evaluating oral glucose tolerance tests (OGTT). This is a test that measures how well your body responds to glucose. Glucose and insulin levels among older adults tend to be higher than among younger people. These higher glucose and insulin values may indicate that your body cannot utilize glucose for energy efficiently. It causes a cycle of elevated glucose values and more insulin production.

More About the Two-hour Oral Glucose Tolerance Test

So what exactly do they do during these oral glucose tests? One of the first things a medical professional will do as part of this test, is take a blood sample to check your fasting glucose levels. You will then drink a sugary solution that contains 75 grams of glucose. After around two hours, the medical professional tests your blood glucose again to see how much it spikes. It's a fairly common test, doctors even use a modified version of it during pregnancy to check for gestational diabetes.

It's also relatively simple and reliable, but it does involve giving people an amount and concentration of sugar that they would likely never consume on their own. Although older adults may have higher glucose levels after the glucose test, the rate of insulin production during the first hour is lower than among younger adults. This means as you age, your body is unable to produce insulin as efficiently when consuming a large glucose load. 

A Study Measuring Glucose Tolerance Over a Lifetime

Here’s a fun fact about how researchers have been studying aging. A clinical research program, called the Baltimore Longitudinal Study of Aging, began in 1958 to study the effects of aging over time. Healthy people of various ages join the study, which analyzes them over several follow-up visits throughout their lifetime.

As you age, glucose tolerance can progress from normal glucose tolerance to impaired fasting glucose, then to impaired glucose tolerance, and finally to type 2 diabetes. However, researchers are still studying the reasons for the progression. As part of this study, subjects underwent oral glucose tolerance tests every two years. Researchers were testing how the glucose levels among people starting with normal glucose tolerance would change over time. After 10 years, they found that of the 488 people with normal glucose tolerance, 14% had progressed to abnormal fasting plasma glucose. 

Nearly half, or 48%, had abnormal two-hour plasma glucose or elevated glucose levels in their blood two hours after the test. This gives you an idea of how your levels can change over time, but what can you do about it?

Risk Factors for Higher Blood Glucose Levels as You Age

By now, you know that as you age, your glucose levels will change. While research is ongoing here as well, some risk factors may contribute to changes in glucose metabolism as you grow older. Aging kidneys may not be able to filter glucose from your blood as well as they used to, and high glucose levels in the bloodstream can have adverse effects on your long-term health. Here are some other factors that may affect your blood glucose levels: 

• An increase in abdominal fat mass (also known as visceral fat).
• Aging-related changes in hormonal production, including reduced testosterone levels and menopause.
• Inflammation, which means eating foods that are anti-inflammatory and being aware of environmental toxins, is essential.
• A slower pace to life. As we grow older, we all slow down, so it’s normal for the amount and type of activity you’re involved in to change or reduce. The important thing is staying active and finding an exercise regimen that you love. This will help manage glucose values and improve quality of life. 
  

How Your Diet Affects Glucose Tolerance as You Age

The oral glucose tolerance test we mentioned above clarifies how differently your body can respond to the same things as you age. But, can you change it all with some dietary modifications? Let’s go back to the oral test, taken after subjects eat either high, medium, or low-carbohydrate diets over three-to-seven days. The study compared the results of older adults with younger adults who consumed identical diets. 

According to the results, eating a low-carbohydrate diet can help with some insulin sensitivity. Even though older adults saw impaired insulin secretion rates following the glucose challenge compared to younger adults, eating a lower-carb diet may be a helpful intervention. Of course, everyone is different, so these results are not a hard-and-fast rule. Regardless of how your body responds, knowing what to expect and how to manage it is the best health decision you can make.