Insulin is a hormone produced by the pancreas and plays a major role in metabolizing carbohydrates, fats and proteins. In addition to being produced naturally by the body, it’s also available as an injectable or inhalable medication to treat certain conditions. Insulin keeps our blood sugar under control, but people with Type 1 and Type 2 diabetes do not produce insulin, enough insulin or can’t use it to regulate blood sugar levels.
What Is an Insulin Injection?
For insulin to be most effective at managing Type 1 or Type 2 diabetes, it must be introduced into the bloodstream. There are four ways to do this:
- Syringe—Insulin can be injected directly into the bloodstream with a syringe and needle.
- Insulin pen—Insulin pens use small needles to inject insulin. They’re more portable and easier to use than syringes. However, they can be more expensive than syringes and aren’t always covered by insurance.
- Insulin pump—Insulin pumps are devices roughly the size of a small cell phone that are semi-permanently attached to fat under the skin. They deliver insulin more accurately and reduce the risk and unpredictability of insulin injections.
- Insulin inhaler—People with diabetes can also use an inhaler to breathe insulin into the lungs. However, insulin pumps or injections must still be used to administer the basal doses that imitate the job of the pancreas.
The amount of insulin that people need in their injections or dosages can vary. When people accidentally inject too much insulin, their blood sugar can drop.
Who Needs Insulin Injections?
Insulin is required for people with Type 1 diabetes and is sometimes necessary for people with Type 2 diabetes. People with Type 1 diabetes typically start off needing two injections of two different types of insulin per day and eventually may need three to four injections of different types of insulin per day.Â
People with Type 2 diabetes may need one insulin injection per day if they aren’t taking medication to help control their disease. Others may need both a single injection of insulin along with oral medication. When oral medications stop working, they may need to increase their insulin injections to twice, three times, or even four times per day.
Is It Safe to Start Exercising After an Insulin Injection?
Because people with both Type 1 and Type 2 diabetes may need multiple injections throughout the day, it can be difficult to fit them into their schedules—especially if they are limited in what they can do afterward.
Exercise is a great way to manage diabetes, but people who inject insulin should avoid injecting it into a part of their body that they will use during their workout. That means that soccer players shouldn’t inject into their legs before practicing or playing a match. Exercising the muscle in that area would cause the insulin to be absorbed too quickly.Â
In addition, people with insulin pumps should ensure they don’t get in the way when they exercise or play sports. If you can’t avoid your pump being interfered with while you exercise or play a sport, talk to a doctor about alternate methods for insulin injection.
Should You Exercise Before or After Taking Insulin?
Hypoglycemia can occur even if you use the right amount of insulin that your body needs, but you exercise more than usual afterward. A hypoglycemia event can occur which has symptoms such as:
- Blurred vision
- Fainting
- Fatigue
- Irregular or fast heartbeat
- Pale skin
Timing insulin injections around exercise can be difficult, and, for some people, it’s a matter of trial and error to achieve the results that give them the most energy during physical activity.
People who take rapid-acting insulin via injection or pump should discuss with the diabetes team the timing of injection prior to activity. Many insulin pumps have features like an exercise mode/activity mode to lessen the chance of hypoglycemia during your workout. People who use inhaled insulin should wait at least 60 to 90 minutes after their dose to avoid low blood sugar while exercising.
You can also exercise before taking insulin, especially if you schedule your workouts for early in the morning. Exercising early makes it less likely that you will experience low blood sugar due to your levels of circulating insulin and cortisol, which is a hormone that increases your insulin resistance.Â
It’s important to check your blood sugar before and after exercising, especially when you are just beginning a new exercise program.
Does Exercise Affect Insulin Absorption?
The location and depth of injections can cause the body to absorb insulin differently. Injections into working muscles can cause the body to absorb insulin at a faster rate.
This effect may be due to many factors that occur during exercise, including increased blood flow, increased body temperature and more. It’s important for people with diabetes to ask their health care providers if it’s safe to exercise and when they should do so depending on their insulin dosages, how often they administer them and the type of injections they receive (rapid-acting vs. long-acting).Â
How Does Insulin Affect Exercise?
Exercise lowers blood sugar, which makes your body more sensitive to insulin, making it easier for muscles to use insulin to absorb sugars after physical activity. In addition, when your muscles contract during exercise, it causes muscle cells to use those sugars for energy whether insulin is available or not.
Short-term exercise lowers blood sugar, and regular exercise can also lower A1C, which is your average blood glucose levels over the past three months.
However, people who take insulin should be aware of their increased risk of hypoglycemia during exercise if they don’t adjust their insulin dose to account for the additional activity. It’s important for people with diabetes to check their blood sugar before exercising and to be prepared to treat it immediately if it occurs.
More to Read
- The Truth About Diabetes and Weight Loss
- Have Diabetes? Take Steps to Protect Your Feet.
- Strength Training for Women in Your 20s, 30s and Beyond
- It’s Time to Get Moving: How to Exercise for Heart Health
Medically reviewed by Angela Ginn Meadow, RN, RDN, CDCES, Program Director, Baltimore Metropolitan Diabetes Regional Partnership, University of Maryland Medical Center.
