PA & Diabetes

• PA & T2DM:

  • 150 min/mod intensity PA had a 26% lower risk of developing type 2 diabetes
  • 300 mins per week of moderate intensity PA had a 36% lower risk of type 2 diabetes
• Benefits of Physical Activity:

  
• Insulin Sensitivity:

  • Exercise enhances insulin sensitivity in skeletal muscle and adipose tissue by:
  • Increasing glucose uptake via GLUT-4 translocation (glucose transporter)
  • Reducing intramuscular lipid accumulation, which can impair insulin signalling
  • Enhancing mitochondrial function and reducing oxidative stress
  • Lowering circulating inflammatory markers that contribute to insulin resistance
  • Impact: This leads to improved glucose disposal, reducing the need for higher insulin levels
• Adiponectin:

  • Aerobic and resistance training, reduces visceral fat, leading to an increase in circulating adiponectin.
  • Adiponectin has anti-inflammatory properties that counteract the pro-inflammatory effects of obesity and diabetes
  • Exercise reduces inflammatory markers (TNF-α, IL-6,CRP), which can enhance adiponectin production
  • Adiponectin enhances endothelial function, improving blood flow and reducing atherosclerosis risk
  • Exercise-induced increases in adiponectin improve lipid profiles and cardiovascular health in diabetes
• Beta-Cell Function:

  • Regular physical activity helps preserve and even improve pancreatic beta-cell function by:
  • Reducing oxidative stress and inflammation in pancreatic islets
  • Enhancing glucose stimulated insulin secretion (GSIS)
  • Reducing lipotoxicity (excess fatty acids that impair beta-cell survival)
  • Improving mitochondrial efficiency and reducing endoplasmic reticulum (ER) stress in beta cells
  • Impact: Exercise slows beta-cell decline, especially in early stage type 2 diabetes
• Glucagon Regulation:

  • Exercise helps regulate glucagon by:
  • Enhancing insulin action, which suppresses glucagon secretion
  • Reducing fasting and postprandial hyperglucagonemia
  • Improving alpha-cell sensitivity to glucose and insulin
  • Impact: This reduces excessive glucose release from the liver, preventing hyperglycaemia
• Hepatic Glucose Production (HGP):

  • The liver plays a central role in glucose homeostasis. Exercise lowers hepatic glucose production by:
  • Increasing insulin sensitivity in the liver, reducing gluconeogenesis (glucose production)
  • Suppressing hepatic glycogenolysis (breakdown of glycogen into glucose)
  • Modulating key enzymes involved in glucose metabolism, such as PEPCK and G6Pase
  • Impact: Less glucose is released into circulation, preventing fasting and post-meal hyperglycaemia
• Aerobic Exercise/PA benefits:

  • A systematic review and meta-analysis including exercise programmes > 150 minutes per week were associated with greater HbA1c reductions (mean change −0.89% - 10 mmol/mol) when compared to programmes involving 150 minutes or less of exercise per week (mean change −0.36% - 4 mmol/mol) (Umpierre et al 2011)
• Aerobic Exercise/PA benefits:

  • A systematic review and meta-analysis of aerobic training variables compared the effects on HbA1c in progressive and non progressive programmes
  • These trials found that 12 weeks of progressive aerobic training reduced HbA1c levels more than those that were non-progressive aerobic training programmes (mean HbA1C difference −0.39% -5 mmol/mol) (Delevatti et al 2019)
• Resistance Exercise/PA benefits:

  • A recent systematic review and meta-analysis has demonstrated that resistance training alone reduces HbA1c levels (mean HbA1c difference −0.39% -5 mmol/mol) and the effects are moderated by greater strength gains (i.e. an increase in muscular strength is associated with a greater reduction in HbA1c levels) (Jansson et al 2021)
• Resistance Exercise/PA benefits:

  • Combined training (aerobic & resistance training) is more effective in lowering HbA1c levels when compared to a single training modality (Schwingshackl et al 2014)
  • However, combined training typically consist of a greater volume when compared to a single training modality
• Aerobic Training - FITT Recommendations for Individuals with Diabetes:

  • Frequency = 3 - 7 days per week
  • Intensity = Moderate (40% - 59% HRR or 11 - 12 RPE) to vigorous (60 - 89% HRR or 14 - 17 RPE)
  • Time = 150 – 300 min of moderate intensity, or 75 – 150 min of vigorous intensity physical activity, or some equivalent combination of moderate intensity and vigorous intensity aerobic physical activity, per week
  • Type = Prolonged, rhythmic activities using large muscle groups (e.g., walking, cycling, swimming)
  • *Reduce sedentary time
• Resistance Training - FITT Recommendations for Individuals with Diabetes:

  • Frequency = A minimum of 2 non-consecutive days/wk preferably 3 days/wk
  • Intensity = Moderate (50 - 69% of 1-RM) to vigorous (70% - 85% of 1-RM)
  • Time = At least 8 - 10 exercises with 1 - 3 sets of 10 - 15 repetitions to near fatigue per set early in training. Gradually progress to heavier weights using 1 - 3 sets of 8 - 10 repetitions.
  • Type = Resistance machines, bands and free weights
• Flexibility Training - FITT Recommendations for Individuals with Diabetes:

  • Frequency = 2 - 3 days per week
  • Intensity = Stretch to the point of tightness or slight discomfort
  • Time = Hold static stretch for 10 - 30 secs; 2 - 4 repetitions of each exercise, achieving a total time of 60 secs for each stretch
  • Type = Static, dynamic, and/or PNF stretching
• Benefits of PA:

  • Adipose:
  • decrease in inflammation
  • decrease in fat mass
  • increase in insulin sensitivity
  • Muscle:
  • increase in glucose uptake
  • increase in glucose and fatty acid oxidation
  • increase in insulin sensitivity
  • Liver:
  • increase in insulin sensitivity
  • decrease in hepatic glucose production
  • decrease in triglyceride accumulation
  • Circulatory:
  • decrease in blood glucose, HbA1C
  • decrease in serum triglycerides and free fatty acids
  • decrease in blood pressure
  • Pancreas:
  • increase in Beta-cell mass
  • increase in insulin
  • decrease in glucagon