Gestational diabetes mellitus (GDM) is a condition where high blood sugar levels develop during pregnancy in individuals who did not have diabetes beforehand. The placenta produces hormones that interfere with the body’s ability to use insulin effectively, leading to insulin resistance and elevated blood glucose. Managing GDM is important for a healthy pregnancy and typically begins with lifestyle adjustments, including changes to diet and physical activity. Regular physical activity directly helps the body process glucose and plays a significant role in improving health outcomes for both the pregnant individual and the baby.
How Physical Activity Regulates Blood Sugar
Exercise directly addresses the core metabolic issue of insulin resistance present in GDM. When a person is physically active, their working muscles require an immediate source of energy, primarily glucose from the bloodstream. Muscle contraction increases the uptake of glucose into the muscle cells through insulin-independent glucose transport. This allows muscle cells to pull glucose from the blood without needing insulin.
This mechanism immediately lowers circulating blood sugar levels following activity. Consistent exercise also leads to cumulative benefits by improving cellular sensitivity to insulin. Physical activity increases the number of glucose transporter type 4 (GLUT4) proteins, which move glucose into the cells. Increased GLUT4 efficiency means the body better responds to available insulin, improving overall glucose control. Aerobic activities, like walking, can reduce the need for insulin for 24 to 72 hours post-exercise.
Safe Exercise Types and Practical Guidelines
A goal of at least 150 minutes of moderate-intensity exercise per week is recommended for pregnant individuals with GDM. This total can be broken down into sessions of 30 minutes, five times a week, or shorter, more frequent sessions throughout the day. Moderate intensity means the activity is challenging enough to elevate the heart rate and breathing, but the individual can still hold a conversation (the “talk test”).
Aerobic exercises are safe and effective options. Walking for 10 to 20 minutes after each main meal is particularly effective for controlling post-meal blood sugar spikes. Incorporating resistance exercise two to three times per week, using light weights or body weight, is also beneficial because it increases muscle mass, the largest mass of insulin-sensitive tissue in the body.
Recommended Activities
- Brisk walking
- Swimming
- Water aerobics
- Stationary cycling
For safety, individuals should avoid activities that carry a high risk of falling, such as downhill skiing or contact sports. After the first trimester, avoid exercises that require lying flat on the back (supine position). This position can cause the uterus to compress the vena cava, reducing blood flow to the heart and potentially to the fetus. It is also important to stay well-hydrated and to avoid exercising in hot or humid weather.
Pregnant individuals should stop exercising immediately if they experience warning signs, including pain in the chest or calves, sudden dizziness, shortness of breath, or vaginal bleeding. Blood glucose levels should be checked before and after activity, especially for those using insulin, to prevent hypoglycemia (low blood sugar). Starting with a low level of activity and gradually increasing the frequency and duration is the safest approach.
Impact on Maternal and Fetal Health Outcomes
Beyond the immediate effect on blood sugar, regular physical activity provides measurable benefits for the overall health of the pregnancy. Exercise helps manage gestational weight gain, keeping it within recommended limits, and consistent activity can reduce the likelihood of needing insulin medication to manage GDM.
For the fetus, a primary concern with uncontrolled GDM is macrosomia, a condition where the baby grows significantly larger than average. Exercise helps mitigate the risk of macrosomia by improving maternal glucose control. Reducing excessive fetal growth can lower the risk of birth trauma and decrease the need for a Cesarean section delivery.
Engaging in regular activity can also help improve the pregnant individual’s mood and reduce stress levels. GDM significantly increases the mother’s long-term risk of developing Type 2 Diabetes later in life, and lifestyle interventions like exercise are a powerful tool in reducing this risk after the baby is born.