Your body has four uses for excess blood sugar: use it as fuel, store it as glycogen, store it as fat, or leave it in your blood. The latter two options leave you fatter and with an above-healthy blood sugar. Strength training can prevent both from occurring.
Here's a list of the ways strength training can make better use of your extra blood glucose.
1. Glycogen. Glycogen is the storage form of glucose. Your muscle and liver cells are the only glycogen locations in your body, with your muscles holding roughly three times the amount of glycogen that your liver can. Since your muscles are the major site of glycogen, your overall capacity to store glucose as glycogen is dictated by your total muscle mass.
It's no secret that we lose muscle as we age. Therefore, our capacity for glycogen decreases with age as well. One four-month study with inactive, diabetic men and women between 60 and 70 years old found glycogen decreased 23% . As mentioned before, if sugar isn't stored as glycogen, then two of the other three options are staying in the blood or getting stored as fat.
However, the same study put a similar group through a strength training program. After four months, the men and women gained muscle and increased their muscle glycogen storage by 31%. The results of each group are featured in the graph below.
2. Immediate Fuel. When performed with a challenging resistance, strength training uses fast-twitch muscle fibers. Fast-twitch muscle fibers are built to perform high-intensity tasks over short periods of time. Examples of these tasks are a 30-second sprint or a one-minute set on the leg press that ends in complete fatigue.
These fast-twitch fibers are relevant because glucose is their primary fuel source. Therefore, strength training, when requiring a moderate to high amount of effort, burns sugar immediately.
3. Insulin Sensitivity. Even though your body want to use excess blood sugar for fuel and storage as glycogen, the doors of the cells aren't always open to glucose, even though insulin tries to open them. As a result, your body produces more insulin, which wears down your pancreas and doesn't always solve the blood sugar problem.
Insulin sensitivity is the willingness of cells to let insulin open their doors so sugar can enter. Strength training increases insulin sensitivity [2, 3]. In fact, the effects of a single strength training session can last for 96 hours .
Strength training helps regulate blood sugar by increasing overall glycogen storage, using sugar for immediate fuel, and by enhancing insulin sensitivity. These individual effects lead to three bigger benefits.
First, overall insulin in your blood decreases, saving your pancreas a lot of unnecessary work . Second, blood sugar decreases [1,3]. This improvement is seen with short and long-term blood glucose measures. Finally, in the case of diabetics who start strength training, the reliance on medications decreases. In the glycogen study discussed earlier, 72% of diabetics in the strength training group reduced or eliminated their medications .
For anyone taking medications to regulate blood sugar, please consult your doctor before starting a strength training program. Medication dosages will likely require adjusting to prevent low blood sugar episodes.
Whether you're diabetic, prediabetic, or just interested in preventing diabetes, strength training offers immediate and long term benefits for your health.