Abstract
Objective: To compare the acute and chronic effects of low-volume high-intensity interval training (HIIT) to moderate-intensity continuous training (MICT) on glycemic control, body composition and continuous glucose monitoring (CGM) in older women with type 2 diabetes (T2D). Methods: Thirty older women (68 ± 5 years) with T2D were randomized in two groups—HIIT (75 min/week) or MICT (150 min/week). Glucose homeostasis (A1c, glucose, insulin, HOMA-IR2) and body composition (iDXA) were measured before and after the 12-week exercise intervention. During the first and last week of training (24-h before and 48-h after exercise), the following CGM-derived data were measured: 24-h and peak glucose levels, glucose variability and time spent in hypoglycemia as well as severe and mild hyperglycemia. Results: While lean body mass increased (p = 0.035), total and trunk fat mass decreased (p ≤ 0.007), without any difference between groups (p ≥ 0.81). Fasting glucose levels (p = 0.001) and A1c (p = 0.014) significantly improved in MICT only, with a significant difference between groups for fasting glucose (p = 0.02). Neither HIIT nor MICT impacted CGM-derived data at week 1 (p ≥ 0.25). However, 24-h and peak glucose levels, as well as time spent in mild hyperglycemia, decreased in HIIT at week 12 (p ≤ 0.03). Conclusion: These results suggest that 12 weeks of low-volume HIIT is enough to provide similar benefit to MICT for body composition and improve the acute effect of exercise when measured with CGM.
Highlights
Type 2 diabetes (T2D) is one of the most prevalent chronic diseases in the world, affecting nearly 425 million individuals in 2017, with a much higher prevalence in the elderly [1]
From the 30 women who were enrolled in this study (HIIT: n = 15 and moderate-intensity continuous training (MICT): n = 15), a subsample of 12 women wore a continuous glucose monitoring (CGM) device (HIIT: n = 6 and MICT: n = 6)
Even if exercise-associated capillary glucose levels were not different between groups, CGM data showed that low-volume high-intensity interval training (HIIT) clinically decreased 24-h and peak glucose levels as well as time spent in mild hyperglycemia, even if women in the MICT had a poorer glycemic control
Summary
Type 2 diabetes (T2D) is one of the most prevalent chronic diseases in the world, affecting nearly 425 million individuals in 2017, with a much higher prevalence in the elderly [1]. The accumulation of multiple acute bouts of exercise can lead to chronic adaptations, such as increased capillary density and mitochondrial content, which are known to be associated with better insulin sensitivity [7,8,9]. In this context, many studies have investigated the benefits of different aerobic exercise modalities on glycemic control, including moderate-intensity continuous training (MICT) and high-intensity interval training (HIIT). Other meta-analyses had shown that higher exercise intensity produces larger improvement in A1c in T2D individuals [13,14]. These meta-analyses pointed out that more evidence is needed to confirm these results and that data are still scarce regarding differential benefits of exercise protocols with varying intensity, frequency, volume, rest time and types of exercise in T2D management [12,14]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
