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| Ideal time of day to exercise for people with type 1 or type 2 diabetes: Study review1

 

The current review of studies, exploring the impact of exercise time of day on general health and glycemia in individuals with diabetes, suggested that the goal of developing an exercise routine that aligns with their life is a priority over timing of exercise. 

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Takeaway

This review summarized the influence of exercise time of day on overall health and glycemia in individuals with diabetes:

  • For individuals living with diabetes, regardless of the time of day or intensity, consistent exercise provides health and glycemic benefits; thus, developing an adherable exercise routine is important.

In individuals with T1D: 

  • Mild to moderate endurance training earlier in the day may yield tangible health benefits with less hypoglycemia 
  • Afternoon exercises (high-intensity interval training (HIIT) or strength training) are better for controlling glucose fluctuations
  • Postmeal endurance exercise normally lowers glucose, but may increase hypoglycemia risk, thus its duration and intensity should be adjusted
  • Premeal endurance activity or HIIT or resistance training pre- or postmeal are beneficial to address the concern of hypoglycemia
  • Regardless of exercise timing, continuous glucose monitoring (CGM) and carbohydrate snacking based on glucose trends are recommended

Why this matters

  • All types of exercises such as endurance, resistance, HIIT, and stretching, provide benefits for individuals with diabetes 
  • Research has aimed at morning vs afternoon and premeal vs postmeal exercise, and the best time of day to exercise remains an open question.
  • This review focused on some recent research on the impact of exercise time of day on general health and glycemia in individuals with diabetes.

Key highlights 

  • Overall practical considerations for individuals with prediabetes or diabetes
  • Having free time to exercise
  • Interactions between the effects of exercise and diabetes treatments
  • Exercise in the morning vs evening seems to have subtle but unique metabolic effects due to hormones, substrate mobilization, and the tissue metabolome/proteome profile

Morning vs afternoon exercise

  • Chronotype refers to individuals’ preference for being a morning or an evening person with respect to patterns of sleep, physical activity, work preferences, eating, and energy level.
  • Morning exercise: Improved metabolism and health; improved overall physical activity adherence and low-calorie intake in obese individuals; better for overall 24-hour glucose levels, greater utilization of endogenous carbohydrates, lipid stores, improved overall insulin sensitivity for 24–48 hours (in a fasting state)
  • Afternoon exercise (particularly vigorous) in T2D: Promoted superior glycemic benefits with lower overnight and next day glycemia due to enhanced insulin sensitivity, improved whole-body and adipose tissue insulin sensitivity, and superior improvements in A1c levels and cardiorespiratory health
  • Afternoon physical activity (moderate to vigorous) in T2D: Potentially greater benefit in cardiorespiratory fitness for females than males 
  • Late-day exercise vs fasted morning exercise in T1D: Greater drop in glucose and increased risk for nocturnal hypoglycemia 
  • Endurance exercise (morning in fasted state vs before dinner): Lower risk of exercise-associated hypoglycemia, 36 hours post-workout and improved overall glycemic time in range 
  • Endurance vs high-intensity exercise during fasting (in the morning) in T1D: Can induce hyperglycemia in individuals with notable increases in circulating lactate levels 
  • Regular resistance training in the morning: Tends to raise glycemia 
  • Glucose variability during recovery with regular resistance training: Higher during morning vs afternoon (improved glucose stability) 


Premeal vs postmeal exercise

  • Premeal exercise in individuals with gestational diabetes or T2D: Improved overall glycemia by potentially lowering premeal glucose concentrations and increasing postmeal insulin sensitivity 
  • Postmeal exercise (mild to moderate) in individuals with prediabetes or T2D: A most beneficial strategy for minimizing postprandial glucose excursions
  • Postmeal exercise (Light to moderate) in T1D: For 15–30 minutes may reduce blood sugar levels; for >30-minute duration can cause hypoglycemia 
  • Premeal endurance exercise in T1D: Can reduce the requirement for pre-exercise carbohydrate snacks to prevent hypoglycemia; consumption of high protein/fat in a meal might delay the time to peak blood sugar, resulting in rebound hyperglycemia after exercise. 
  • Pre- or post-meal HIIT and strength training vs endurance training in T1D: Lower risk of hypoglycemia 
  • CGM should be promoted regardless of when activity is performed in individuals with T1D with highly personalized glucose responses to exercise 

 
Exercise snacking

  • A protocol comprising 3 short, discrete exercise sessions one before each meal helps flatten postmeal glucose levels and reduce mean glucose levels by ~10 mg/dL over 24 hours vs a day without activity
  •  5-minute warm-up walk
  • Six inclined treadmill walking sets of 1 minute each (at 90% of the participant's maximum heart rate) with a 1-minute walk or light resistance exercise recovery between sets
  • A 3-minute walk-down
  • Similar results were obtained with a 6-minute moderate-intensity stair-climbing intervention done 90 minutes postmeal in men with impaired glucose tolerance 

    1.    Riddell MC, Turner LV, and Patton SR. Is there an optimal time of day for exercise? A commentary on when to exercise for people living with type 1 or type 2 diabetes. Diabetes Spectr. 2023;36(2):146–50. doi: 10.2337/dsi22-0017. PMID: 37193212.

MAT-DK-2300553 v.1.0 22.11.2023