The best time of day to exercise for better blood sugar control

Medically reviewed by Elizabeth Barnes, RDN

Takeaway

• Afternoon and evening exercise improves blood sugar control and insulin sensitivity more than morning exercise, especially for people with type 2 diabetes.
• Moderate to high-intensity workouts, such as jogging or resistance training, are most effective for managing blood sugar levels.
• Exercising in alignment with your natural chronotype leads to better outcomes than forcing workouts at inconvenient times.

Advice on exercise is typically based on how and how much you move, but new research suggests that when you move may matter just as much, especially if you experience challenges with blood sugar control. Understanding this connection could change how you schedule your workouts and help you get more benefit from the exercise you're already doing.

When Is the Best Time of Day to Exercise for Blood Sugar Control?

A recent review published in Trends in Endocrinology & Metabolism aimed to answer this question by examining how exercise at different times of day affects insulin sensitivity and glucose regulation. The researchers found that afternoon and evening exercise had greater benefits for blood sugar control than morning exercise in people with type 2 diabetes. There were also differences observed related to how intense the workouts were.

The reasons for this come down to how impairments in blood sugar regulation affect your body's natural clock, the circadian rhythm, and how the timing and intensity of exercise help reset it.

According to the review, exercise acts as a "zeitgeber". This means it influences the internal biological clock, potentially helping reset what's out of balance. In fact, exercise has such strong time-keeping effects that it can be used to help treat circadian rhythm disorders.

While this review specifically examined the effects of exercise timing on type 2 diabetes, the findings could still benefit people seeking ways to optimize their overall blood sugar regulation.

Why Afternoon and Evening Exercise Is Best

Afternoon and evening exercise (particularly moderate to high intensity) improves blood sugar control and insulin sensitivity. It's also associated with lower levels of stress hormones and inflammation. On the other hand, morning exercise has minimal effect and, in some cases, may increase blood sugar levels and worsen existing metabolic issues.

Here are some of the reasons why this may be the case:

• There are lower levels of hormones like cortisol and growth hormone later in the day, which means the increase in blood sugar from exercise has minimal impact.
• Your muscles have the greatest ability to perform later in the day, which may improve glucose uptake and help stabilize blood sugar levels.
• Exercise has "zeitgeber" effects when it's timed correctly.
• Inflammatory markers and blood sugar levels are higher after morning exercise compared to afternoon exercise, especially among individuals with type 2 diabetes.
• You've typically eaten lunch by the time afternoon or evening exercise occurs, naturally elevating blood sugar levels that can then be lowered through a workout.

What This Means for Your Routine

Based on the findings of this review, you can start using exercise timing to your advantage. Here are some ways you can get the most out of your exercise for blood sugar management:

• Try shifting your workouts later in the day: The most consistent finding from the research is that afternoon and evening exercise outperforms morning exercise for blood sugar control. If you're having trouble regulating your blood sugar levels, even shifting your workout timing could affect how your body responds.
• Move with sufficient intensity: Timing and intensity of a workout interact. Throughout the week, engaging in moderate to vigorous effort (e.g., brisk walking, jogging, cycling, or resistance training) is what consistently showed improvements in blood sugar control and insulin sensitivity in the studies reviewed.
• Factor in your chronotype: If you're a committed early bird, the answer isn't necessarily to force yourself into a post-work gym session you'll dread and eventually abandon. Exercising in alignment with your chronotype (your natural preference for morning or evening activity) produces better outcomes than exercising at arbitrary times just because "you're supposed to".
• Use glucose readings as a personal experiment: If you have access to a continuous glucose monitor (CGM) or check your blood sugar regularly, try logging your readings before and after workouts at different times of day over a few weeks. This can help you identify patterns to help figure out what's best for your body.

It's always smart to talk to your healthcare team before making big changes, especially if you have diabetes. Shifting your exercise timing can affect how you need to time your glucose-lowering medications and meals.

Finally, if you can't adjust your workouts later and don't think it's meaningfully affecting your blood sugar regulation, don't stress. Getting active regularly, when it fits your lifestyle, is always better than not moving at all.

Read the original article on Verywell Health