“It’s important to define the best way for people with type 1 diabetes to exercise so that blood sugar doesn’t drop too low, yet they can still reap all the benefits of aerobic exercise,” Dr. Ronald Sigal, an endocrinologist at the University of Calgary told Reuters Health.
Those with type 1 diabetes, a condition in which the body does not produce its own insulin, a hormone needed to convert food into fuel, risk low blood sugar during exercise. Blood sugar that drops too low can lead to poor coordination, unconsciousness or even coma.
Twelve fit people with type 1 diabetes, who already ran and lifted weights at least three times per week, participated in the new study. The 10 men and two women averaged 32 years old.
At one monitored exercise session, participants did 45 minutes of treadmill running followed by 45 minutes of weight lifting. They switched the order for the second session.
Researchers measured blood sugar levels before, during and after exercise for each participant.
When participants did aerobic exercise first, blood sugar dropped to lower levels and remained for the duration of the workout than when they lifted weights first and ran second.
Lifting weights first was also associated with less severe drops in blood sugar hours after exercise, and post-exercise drops that did occur tended to last a shorter period of time.
The study, published in Diabetes Care, supports previous research showing that aerobic exercise causes a more rapid decrease in blood sugar than weightlifting.
Your muscles utilize sugar very quickly in aerobic exercise,” Dr. Vivian Fonseca, chief of endocrinology at Tulane University Medical School told Reuters Health.
Researchers acknowledge that other factors, which they did not measure, could be at work, rather than the exercise order. They did not account for levels of a number of hormones that could also lead to changes in blood glucose during exercise.
Nor did they have control over participants’ food and activity choices prior to exercise. The authors loosely set up conditions to have the study reflect real-life conditions faced by people with type 1 diabetes.
Because study participants were young, active people with type 1 diabetes, it’s not clear whether the findings would apply to less fit people with type 1 diabetes or people with type 2 diabetes.