Sex-related differences in fuel utilization and hormonal response to exercise: implications for individuals with type 1 diabetes

Abstract

Applied Physiology, Nutrition, and Metabolism D r a f t 2 Abstract Sex-related differences in metabolic and neuroendocrine response to exercise in individuals without diabetes have been well established. Men and women differ in fuel selection during exercise, in which women rely to a greater extent on fat oxidation, whereas males rely mostly on carbohydrate oxidation for energy production. The difference in fuel selection appears to be mediated by sex-related differences in hormonal (including catecholamines, growth hormone, and estrogen) response to different types and intensities of exercise. In general, men exhibit an amplified counter-regulatory response to exercise, with elevated levels of catecholamines compared to women. However, women exhibit greater sensitivity to the lipolytic action of the catecholamines and deplete less of their glycogen stores than men during exercise, which suggests that women may experience a greater defense in blood glucose control after exercise than men. Conversely, little is known about sex-related differences in response to exercise in individuals with type 1 diabetes (T1D). A single study investigating sex-related differences in response to moderate aerobic exercise in individuals with T1D found sex-related differences in catecholamine response and fuel selection, but changes in blood glucose were not measured. To our knowledge, there are no studies investigating sex-related differences in blood glucose responses to different types and intensities of exercise in individuals with T1D. This review summarizes sex-related differences in exercise responses that could potentially impact blood glucose levels during exercise in individuals with T1D and highlights the need for further research.

Vigorous Intervals and Hypoglycemia in Type 1 Diabetes: A Randomized Cross Over Trial

“…The present study is unique in that we included participants of both sexes and individuals with T1D who did not meet physical activity guidelines, according to self-report. Several hormonal responses to exercise and consequently fuel selection, are different between the sexes in individuals without diabetes 39 . There is no evidence to indicate that this is not also the case in individuals with T1D, and as such, the inclusion of both males and females may have increased the variability in the hormonal response to exercise 39 .…”

“…Several hormonal responses to exercise and consequently fuel selection, are different between the sexes in individuals without diabetes 39 . There is no evidence to indicate that this is not also the case in individuals with T1D, and as such, the inclusion of both males and females may have increased the variability in the hormonal response to exercise 39 . It is also possible that the protective effects of vigorous intensity exercise on hypoglycemia risk are more pronounced in individuals who train on a regular basis.…”

Carbohydrate Requirement for Exercise in Type 1 Diabetes: Effects of Insulin Concentration

“…37 Data on healthy people and T1D patients were pooled together 39 as well as those of both genders, which effects are still under debate. 40 Patients might also exercise at relatively long time distances from the last insulin bolus, when insulin levels might be too low, thus resulting in hyperglycemia because of an excess glucose released from the liver, 31,32 not taken up by the working muscles.…”

<p>The Athlete with Type 1 Diabetes: Transition from Case Reports to General Therapy Recommendations</p>

“…To date, this publication offers the most detailed exercise safety guidelines available to the athlete or active individual with type 1 diabetes, including advice for insulin dosage management, dietary management, and hydration for specific levels of blood glucose, relative to different intensities and durations of exercise. However, it should still be noted that most of the studies on which this advice is based were performed on young, fit, males, and do not take into account potential age-63 and sex-related63,64 differences in exercise responses. As such, it is still advisable to individually tailor exercise and physical activity recommendations to the individual.…”