It’s long been known that regular exercise is associated with numerous health benefits, including lower blood glucose levels in people with diabetes. In fact, as we noted recently, exercise appears to increase the amount of time people with type 1 spend in their target glucose range — but only on the days that they exercise. Recent research has also shown that exercise may reduce the cardiovascular risks associated with controlled hypertension.
Over the years, studies have also shown that exercise may have mental health benefits, reducing the risk of depression and anxiety. But there has often been an unanswered question in these studies — does getting regular exercise directly lower the risk of depression and anxiety, or does it do this by leading to improved cardiovascular health? This question is important because if the benefits are direct, pretty much anyone could see mental health benefits from exercise. But if they’re indirect and depend on cardiovascular fitness, then you’d have to reach a certain level of fitness to see your mental health risk improve.
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A recent study attempted to answer this question, by measuring participants’ cardiorespiratory fitness and factoring this into the results.
Separating exercise and fitness
The study, published in the journal Mental Health and Physical Activity, looked at exercise habits and mental health in 36,595 people who took part in the Swedish Health Profile Assessment. This general health assessment was offered to all employees of companies connected to occupational or health services.
Participants reported how frequently they performed structured exercise in the last 30 days, and completed a six-minute peak oxygen uptake test using a stationary cycle ergometer (a device that measures energy expenditure). Participants also reported any leisure-time physical activity, and reported any symptoms of depression and anxiety based on a questionnaire designed to measure these symptoms in detail.
The researchers found that compared with participants in the lowest exercise frequency category — those who reported never or sometimes performing exercise — those who exercised one to two times per week were 25% less likely to report frequent symptoms of depression or anxiety, while those who exercised three or more times per week were 28% less likely to report these symptoms frequently. In their initial analysis, the researchers also found that people with greater cardiorespiratory fitness were less likely to report frequent depression or anxiety symptoms, with fitness level directly corresponding to this risk.
But when the researchers took leisure-time physical activity into account, they found that the association between physical fitness and mental health disappeared. That is to say, people who tested higher for cardiorespiratory fitness — and reported fewer symptoms of depression and anxiety — were also getting more leisure-time physical activity. Those with greater physical fitness, but who didn’t get as much leisure-time activity, were no more likely to have better mental health than people who tested lower for physical fitness.
These findings suggest that the mental health benefits of physical activity occur directly, and don’t depend on seeing improved physical fitness — although improved physical fitness tends to happen as a result of this activity, too.
More reasons for regular physical activity
While there are no guarantees that any single person will see mental health benefits, this study adds to the strong evidence that regular physical activity is tied to a lower risk of depression and anxiety. It also emphasizes the “regular” part of the activity equation, since getting less leisure-time physical activity was tied to a higher risk of depression or anxiety symptoms than getting more leisure-time physical activity for someone at the same level or cardiorespiratory fitness.
If you struggle with symptoms of depression or anxiety, it’s important to talk with your doctor about strategies — including exercise and less-structured, fun forms of physical activity — that may help you reduce your symptoms and improve your quality of life.
Want to learn more about exercising with diabetes? Read “Add Movement to Your Life,” “Picking the Right Activity to Meet Your Fitness Goals” and “Seven Ways to Have Fun Exercising.”