Differences in the acute effects of aerobic and resistance exercise in subjects with type 2 diabetes: results from the RAED2 Randomized Trial

Abstract

Objective: Both aerobic (AER) and resistance (RES) training, if maintained over a period of several months, reduce HbA1c levels in type 2 diabetes subjects. However, it is still unknown whether the short-term effects of these types of exercise on blood glucose are similar. Our objective was to assess whether there may be a difference in acute blood glucose changes after a single bout of AER or RES exercise.

Study design: Twenty-five patients participating in the RAED2 Study, a RCT comparing AER and RES training in diabetic subjects, were submitted to continuous glucose monitoring during a 60-min exercise session and over the following 47 h. These measurements were performed after 10.9+0.4 weeks of training. Glucose concentration areas under the curve (AUC) during exercise, the subsequent night, and the 24-h period following exercise, as well as the corresponding periods of the non-exercise day, were assessed. Moreover, the low (LBGI) and high (HBGI) blood glucose indices, which summarize the duration and extent of hypoglycaemia or hyperglycaemia, respectively, were measured.

Results: AER and RES training similarly reduced HbA1c. Forty-eight hour glucose AUC was similar in both groups. However, a comparison of glucose AUC during the 60-min exercise period and the corresponding period of the non-exercise day showed that glucose levels were lower during exercise in the AER but not in the RES group (time-by-group interaction p = 0.04). Similar differences were observed in the nocturnal periods (time-by-group interaction p = 0.02). Accordingly, nocturnal LBGI was higher in the exercise day than in the non-exercise day in the AER (p = 0.012) but not in the RES group (p = 0.62).

Conclusions: Although AER and RES training have similar long-term metabolic effects in diabetic subjects, the acute effects of single bouts of these exercise types differ, with a potential increase in late-onset hypoglycaemia risk after AER exercise.

Trial registration: ClinicalTrials.gov NCT01182948.

Figure 1. Study flow diagram.

Figure 2. Schematic overview of the study design.

The CGMS sensor was inserted at 8:30–9:30 am. Glucose concentrations were recorded over a 48-h period, starting at 6:30 pm of the same day, corresponding to the beginning of the 60-min exercise session. Several time periods were separately analyzed: the exercise period (6:30–7:30 pm), the subsequent nocturnal period (1:00 am–5:00 am) and the 24-h period following the beginning of the exercise session (exercise day), as well as the corresponding time periods of the following (non-exercise) day. The CGMS was removed at 7:30–8:30 pm of the non-exercise day. Meal times were between 6:30–8:30 am for breakfast, 12:30 am to 2:00 pm for lunch, 3:30–4:30 pm for a snack and 8:00–9:30 pm for dinner.

Figure 3. Mean glucose concentrations behavior during selected periods, in the aerobic (A) and the resistance (B) groups.

Upper panels: glucose concentrations during the 60-min exercise session and the corresponding period of the non-exercise day. Lower panels: glucose concentrations during the nocturnal sleeping period (01:00–05:00 am) of the two days. White circles indicate glucose values in the exercise day, and black circles those in the non-exercise day. P values refer to differences in glucose concentration AUCs between the exercise day and the non-exercise day.