A possible link between exercise-training adaptation and dehydroepiandrosterone sulfate- an oldest-old female study

Abstract

The purpose of this study was to determine the association between the level of salivary dehydroepiandrosterone sulfate (DHEA-S) and the magnitude of adaptation to exercise training in insulin sensitivity for aged females. A group of 16 females, aged 80-93 years old, was divided into 2 groups according to their baseline DHEA-S levels: Lower Halves (N = 8) and Upper Halves (N = 8), and participated in a 4-month exercise intervention trial. Insulin response with an oral glucose tolerance test (OGTT), cholesterol, blood pressure (BP), motor performance, and DHEA-S were determined at baseline and 4 months after the training program. Glucose tolerance and body mass index (BMI) remained unchanged with training for both groups. Insulin, fasted cholesterol, diastolic blood pressure, reaction time, and locomotive function were significantly lowered by training only in the Upper Halves group. Changes in the area under curve of insulin (IAUC) were negatively correlated with the baseline DHEA-S level (R= - 0.60, P < 0.05). The current study provides the first evidence that oldest-old subjects with low DHEA-S level appear to be poor responders to exercise-training adaptations.

Figure 1

Glucose tolerance and insulin response in Lower Halves group of DHEA-S before (Pre) and after 4-month exercise training (Post). Glucose levels (A) and insulin level (B) were measured under 75 grams of oral glucose challenge. Glucose tolerance and insulin response were not changed by exercise training in the oldest-old subjects with lower DHEA-S level, suggesting insulin sensitivity was not improved by exercise training.

Figure 1

Glucose tolerance and insulin response in Lower Halves group of DHEA-S before (Pre) and after 4-month exercise training (Post). Glucose levels (A) and insulin level (B) were measured under 75 grams of oral glucose challenge. Glucose tolerance and insulin response were not changed by exercise training in the oldest-old subjects with lower DHEA-S level, suggesting insulin sensitivity was not improved by exercise training.

Figure 2

Glucose tolerance and insulin response in Upper Halves group before (Pre) and after 4-month exercise training (Post). Glucose (A) and insulin (B) levels were measured following a 75 gram bolus of oral glucose challenge. * significant difference from Pre (P < 0.05). While glucose tolerance remained unchanged, insulin response was lowered by exercise training in the subjects with higher DHEA-S level, suggesting that insulin sensitivity was improved in the oldest-old subjects with higher DHEA-S.

Figure 2

Glucose tolerance and insulin response in Upper Halves group before (Pre) and after 4-month exercise training (Post). Glucose (A) and insulin (B) levels were measured following a 75 gram bolus of oral glucose challenge. * significant difference from Pre (P < 0.05). While glucose tolerance remained unchanged, insulin response was lowered by exercise training in the subjects with higher DHEA-S level, suggesting that insulin sensitivity was improved in the oldest-old subjects with higher DHEA-S.

Figure 3

Relationship between baseline DHEA-S level and changes in the area under curve for glucose (GAUC change) and insulin (IAUC change) in the oldest-old subjects. No correlation between GAUC change and baseline DHEA-S level was found (3A); IAUC change was negatively correlated with baseline DHEA-S level (3B) (R = - 0.60, P < 0.05). This result indicates that the magnitude of exercise training effect on insulin sensitivity is associated with DHEA-S level.

Figure 3

Relationship between baseline DHEA-S level and changes in the area under curve for glucose (GAUC change) and insulin (IAUC change) in the oldest-old subjects. No correlation between GAUC change and baseline DHEA-S level was found (3A); IAUC change was negatively correlated with baseline DHEA-S level (3B) (R = - 0.60, P < 0.05). This result indicates that the magnitude of exercise training effect on insulin sensitivity is associated with DHEA-S level.