This is the best time to exercise to improve blood sugars, according to a new study

• The timing of exercise can affect blood sugar levels in people with type 2 diabetes, a new study finds.
• People who exercised in the afternoon were more likely to have lower blood sugar levels.
• Experts point out that exercising at any time of day is important for diabetes management.

---

Exercise is a useful tool in blood sugar management for people with type 2 diabetes, but new research has found When you exercise can make a big difference, especially, a certain time of day.

The study, which was published in the journal Diabetes care, followed 2,416 people with type 2 diabetes who participated in the Look AHEAD study, a randomized clinical trial designed to examine the long-term effects of lifestyle interventions in overweight or obese people with type 2 diabetes. For the study, participants wore an accelerometry recording device around their waist to measure their physical activity.

Researchers found that people who engaged in moderate to vigorous physical activity in the afternoon had the greatest reduction in blood glucose (also known as blood sugar) levels during the first year. It was quite significant that the afternoon athletes had a 30% to 50% lower drop in blood sugar levels than that of other groups.

The researchers also looked at data from the study’s fourth year and found that the afternoon exercise group maintained that reduction in blood glucose levels. They also had the best chance of stopping their glucose-lowering medications.

High blood sugar levels can put people with type 2 diabetes at risk for serious complications of the disease, including heart disease, vision problems and kidney disease, according to the American Diabetes Association (ADA).

We’ve known for a long time that in people with type 2 diabetes, physical activity is important to help manage blood sugar, says study co-author Roeland JW Middelbeek, MD, assistant professor of medicine at the Joslin Diabetes Center. Many studies have looked at how many people should do this, but there weren’t yet any details on when to do it. This is the recognition that the body’s response to blood sugar management is different during different times of the day.

But why might afternoon exercise help with blood sugar management? Here’s the deal.

How does exercise affect blood sugar?

At baseline, any form of exercise is known to help lower blood sugar, explains Dr. Middelbeek, and there are a number of ways this can happen.

Exercise increases sensitivity to insulin, a hormone that helps blood sugar get into the body’s cells so it can be used for energy, says the ADA. This helps muscle cells make better use of available insulin to absorb glucose during and after your workout.

When your muscles contract during physical activity, it also helps your cells absorb glucose and use it for energy, whether or not insulin is available, notes the ADA. Over time, this can help lower blood sugar levels and make insulin in your body work more efficiently, says Dr. Middelbeek.

Exercising regularly also helps build lean muscle mass, and this can help boost your metabolism, which can also indirectly help lower blood sugar, says personal trainer and nutritionist Albert Matheny, MS, RD, CSCS, co-founder of the SoHo Strength Lab and Promix Nutrition.

Regular exercise also has lasting benefits for blood sugar management. Over the long term, it also helps improve the body’s sensitivity to insulin which is beneficial for metabolic health as it helps keep blood sugar levels stable, says Christoph Buettner, MD, Ph.D., head of the Division of Endocrinology, Metabolism and Nutrition at Rutgers Robert Wood Johnson Medical School.

Why can afternoon exercise help with blood sugar management?

Importantly, the study didn’t prove that afternoon exercise causes reductions in blood sugar, it just found a link. But there are some theories as to what might be behind it.

It makes sense that the timing of your workout could impact your blood sugar levels, says Matheny. Blood sugar rises after eating.

But usually your blood sugar is highest in the afternoon because you’ve probably already had breakfast, lunch and maybe even a snack, she says. Working out at that point will help lower or manage your blood sugar, she says.

Dr Middelbeek agrees. If you’ve been eating, blood sugar generally spikes, and exercise can help bring it down, he says.

Your body’s sensitivity to insulin can also increase during the afternoon, says Dr. Buettner. Insulin sensitivity tends to be higher in the afternoon than in the morning, which may increase the metabolic benefits of exercise, he says. It will also result in lower bloodstream glucose and lipid levels in the evening, which will last throughout the night and this is likely beneficial.

What if you can’t train in the afternoon?

Dr. Middelbeek says people with type 2 diabetes should consider exercise as part of their treatment plan, along with eating a healthy diet and taking glucose-lowering medications, if recommended by a doctor.

We recommend that people get active and stay active to the extent they can, she says. The more people can stay active, the better for their overall health. Dr. Buettner only recommends that people with type 2 diabetes be prepared for blood sugar levels to drop too low during or after exercise, especially if they take supplemental insulin or blood sugar-lowering medications. Exercise can sometimes cause blood sugar levels to drop too low (hypoglycemia), he says. Carry a fast-acting carbohydrate source, such as glucose tablets or a small snack, in case you experience hypoglycemia during or after exercise.

If you can’t exercise in the afternoon, which, Dr. Middelbeek acknowledges, is when a lot of people work, he advises just making sure you get exercise, period.

Many of us who study this will still say that anytime you can exercise is good, he says. We know that many people are not active in the afternoon. Anytime people can be active that’s great. But the afternoon may be slightly better for glucose management.