The benefits of cycling for those with diabetes

Back in April I shared with you a study that suggests that exercise can help reduce the risk of developing diabetes in those who are overweight or obese. In fact, "For every additional 17 minutes of brisk daily walking, the participants saw a 6% reduction in their risk of developing diabetes." Yet exercise is also important for those who already have diabetes: it helps improve glucose control and cardiovascular fitness and reduces the risk of overall mortality as well as mortality due to heart disease.

An international team of researchers noted that one of the greatest barriers to regular exercise is time. What if people with diabetes started using a bicycle for those short-to-medium trips people make regularly, such as commuting? What impact might that have on their risk of mortality? (JAMA Int Med 2021;181(9):1196-1205)

The European Prospective Investigation into Cancer and Nutrition (EPIC) is an ongoing study that began recruiting participants in 10 Western European countries between 1992 and 2000 and continues today. Over 500,000 men and women are included, but for today's research the authors focused on the just over 7,400 people who had been diagnosed with diabetes (any type) before the study began.

Upon recruitment the participants responded to a detailed lifestyle survey that allowed the researchers to assess the participants' levels and types of physical activity, from the nature of their work (sedentary? hard physical labor?) to any leisure time exercise as well as activities of daily life.

The participants also filled out a detailed dietary questionnaire as well as demographic and medical history surveys. Their height, weight, and waist circumference was recorded and a medical history taken. Five years later, the surviving participants again responded to a lifestyle questionnaire.

After an average of 10 years of follow-up, the authors compared the amount of cycling the surviving participants reported at the start of the study with that of those participants who passed away.

After taking into account a number of variables, from Mediterranean diet score to other health conditions such as high blood pressure, the authors found that compared to those who did not bicycle at the start of the study, those who averaged less than 1 hour of cycling per week were 22% less likely to die of any cause. Those who cycled between 60 and 149 minutes per week reduced their risk of death by 24%, and those who bicycled between 150 and 299 minutes per week were 32% less likely to die of any cause.

With the results from the follow-up survey, the authors could also look at those who took up cycling after the initial survey, those who stopped cycling, and those who reported cycling at both surveys.

Unsurprisingly, those who maintained their cycling habit enjoyed the lowest risk of mortality from heart disease or any other cause - a drop of about 36%. But those who did not initially bicycle but reported some cycling - any amount - at the second survey still saw their overall risk of death fall by 34%. Similar results held for risk of death from heart disease.

What this means for you

Certainly there are plenty of barriers to cycling: first, you need a bicycle, then you need somewhere safe to ride it.

What I take from this study is that yes, cycling is great exercise, but any moderately intense exercise that you can do consistently will help those with diabetes reduce their risk of mortality. Aim for at least 150 minutes of exercise per week - that's 30 minutes per day, 5 days per week.

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