Can exercise improve nerve health of the heart in patients with diabetes?

This review looked at whether exercise can improve heart rate variability (HRV) for patients with type 2 diabetes (T2D). It found that exercise improved HRV, which indicates better nerve health of the heart.

Over time, high blood glucose (sugar) from diabetes can cause nerve damage or neuropathy. People with diabetes often develop neuropathy of the hands and feet, which can cause loss of sensation. However, nerve damage can also develop in the nerves that control the heartbeat. This is known as cardiac autonomic neuropathy (CAN). CAN is a common complication of diabetes, but it can be serious. People with T2D and CAN have an increased risk of a heart attack. 

The heart rate adjusts when you change your physical activity, and in response to emotions such as fear. These changes in heart rhythm are directed by nerve signals within the heart and from the brain. For people with CAN, the heartbeat does not adjust as well. CAN can cause a faster resting heart rate than normal. It can also cause dizziness when standing up if the heart does not adjust to the new position.

One simple test of cardiac nerve health is heart rate variability (HRV; how much the time between heartbeats varies). The amount of time between heartbeats is not exactly the same for every beat, even at rest. This variation is normal and healthy and indicates that the heart can adjust. However, people with T2D have less HRV than normal.

Exercise, particularly aerobic exercise, can improve heart health. In people without diabetes, exercise can also improve HRV. However, it is not clear whether exercise can improve cardiac nerve health for people with T2D.

This review included 21 studies with 523 patients with T2D. Most of the studies recruited patients who were not physically active. During the studies, 472 patients had a specific exercise regimen. They were compared to 151 control patients who did not have an exercise schedule. The types of exercise included endurance, resistance, and high-intensity interval training (HIIT). The studies lasted between 1 and 12 months. All of the studies measured resting HRV at the beginning and end of the study.

After exercise, there was a moderate improvement in HRV. Supervised or group exercise led to a large improvement in HRV.

The studies used several different types of exercise. Endurance training led to a significant improvement in HRV. Additionally, HIIT led to a significant improvement in some ways of measuring HRV. All of the types of exercise trended toward an improvement in HRV. However, no changes were seen in HRV in the control group. 

This analysis found that exercise improved HRV for people with T2D.

HIIT, which uses short bursts of intense exercise, tended toward more HRV improvement than endurance training. However, more studies are needed. The number of participants in each study was small.

Talk to your doctor about your risk of CAN. If you use at-home HRV monitoring, talk to your doctor about the results. Also, talk to your practitioner about how to adapt your exercise schedule for your health conditions.