Understanding the gut microbiome through a fitness intervention of aerobic and resistance training for individuals with type 2 diabetes mellitus (GUTFIT: A Study Protocol).

Exercise exhibits vast inter-individual variability in glycemic response in individuals with T2DM, and gut microbial diversity and exercise intensity may be factors influencing this variability.

• The interplay between exercise intensity, microbial adaptations, and glycemic outcomes in individuals living with T2DM remains unclear.
• Exercise is described as 'a cornerstone of type 2 diabetes (T2DM) management.'
• This gap in knowledge motivates the GUTFIT study protocol.

The GUTFIT study is a parallel-group, single-blinded, randomized controlled trial registered as NCT06268743.

• The trial involves 40 adult participants (n = 20 female) living with T2DM.
• Participants are randomized to one of two exercise intensity arms for 16 weeks.
• All outcome measures are tested pre- and post-intervention.
• The design is described as a 'parallel-group, single-blinded, randomized trial.'

The vigorous-intensity exercise intervention consists of aerobic training at 70-80% heart rate reserve and resistance training at 8-10 repetitions of 75-80% maximal strength.

• This arm is compared against a moderate-intensity exercise arm.
• Both aerobic and resistance training components are combined in the vigorous-intensity protocol.
• The intervention duration is 16 weeks.

The moderate-intensity exercise intervention consists of aerobic training at 45-55% heart rate reserve and resistance training at 12-15 repetitions of 65-70% maximal strength.

• This arm serves as the comparator to the vigorous-intensity exercise arm.
• Both aerobic and resistance training components are combined in the moderate-intensity protocol.
• The intervention duration is 16 weeks.

Glycemia will be measured via glycated hemoglobin (HbA1c) and gut microbial composition will be determined from fecal samples using next-generation sequencing of 16S ribosomal DNA genes.

• Next-generation sequencing platform specified is Illumina MiSeq.
• 16S ribosomal DNA gene sequencing is used to determine gut microbial composition.
• Both primary outcome measures are assessed pre- and post-intervention.

A secondary objective of the GUTFIT study is to explore whether decreases in glycemia after exercise are associated with alterations in gut microbial community architecture and diversity.

• The study aims to determine if there is an 'intensity-dependent association between exercise-induced changes in glycemia and gut microbial diversity.'
• Gut microbial community architecture and diversity are both outcomes of interest.
• This objective addresses whether the relationship between glycemic change and microbiome change is moderated by exercise intensity.