Just 2000 Steps a Day Keeps Diabetes Risk Away

Walking not only prevents weight gain in middle age but also helps prevent or delay diabetes....

Terry Dwyer, AO, MD, MPH, of the Murdoch Children's Research Institute in Melbourne, Australia, found that middle-age Australians who increased their daily step count over five years maintained significantly higher insulin sensitivity at the end of that period than those who didn't boost their steps (P=0.03). This effect appeared largely due to lower adiposity and was independent of calories consumed, the group reported.

If causal, sedentary individuals who change their habits to walk an extra 2,000 steps (about one mile) a day might expect to shave 0.16 kg/m2 off their body mass index and boost insulin sensitivity by 2.76 units, the researchers estimated.

A relatively inactive person who gets to the goal of 10,000 steps (about five miles) per day could expect their BMI to drop 0.83 kg/m2 and their insulin sensitivity to rise 13.85 units -- a 12.8% increase from the mean for men and 11.5% for women.

Thus, sedentary individuals who reach 10,000 steps (about five miles) per day might expect a three-fold improvement in HOMA insulin sensitivity compared with increasing steps to a recent recommendation of 3,000 steps five days a week, the investigators projected.

Prior trials had suggested that exercise interventions fight insulin resistance, but Dwyer's group said their results suggest that real-world efforts to step-up physical activity are effective as well.

The researchers studied a group of 592 nondiabetic adults in the state of Tasmania who provided pedometer data for two days in both 2000 and 2005 as part of the population-based AusDiab Study, designed to determine the prevalence of diabetes and related risk factors in Australia.

At the beginning of the study, the average age was 51.4 for men and 50.3 for women.

Many participants were already overweight (57.4% of men, 36.9% of women) or obese (17.7% of men, 16.0% of women) at the outset and then gained further weight over the five year period.

Most got more sedentary as well with 65% showing a decline in step counts from 2000 to 2005, although another 35.5% increased their step counts.

Each additional 1,000 steps added to the daily count at the end of the five-year period was independently associated with 0.08 kg/m2 lower BMI (95% confidence interval 0.04 to 0.12) and 0.15 cm lower waist-to-hip ratio (95% CI 0.07 to 0.23).

Insulin sensitivity was also 1.38 HOMA units (95% CI 0.14 to 2.63) higher per 1,000 extra steps in 2005 versus 2000. The mean HOMA insulin sensitivity was 108.0 units for men and 120.4 for women in 2005.

The effect on insulin sensitivity dropped to insignificance after adjustment for body mass index in 2005, suggesting that change in adiposity with higher step activity was the mediator.

The researchers noted that their study couldn't determine the timing of changes in number of steps taken and likely missed some activity undertaken by study participants since pedometers only capture up-and-down motion.

Also, the actual energy expenditure associated with a certain step count varies by age, sex, height, leg length, and gait, they pointed out.