Abstract
The importance of physical activity for healthy aging has been clearly shown. Evidence from the Look AHEAD trial, a lifestyle intervention for overweight individuals who have type 2 diabetes, provides further evidence for the importance of physical activity. Overall, this intervention provides a potential model for improving the health of older adults.
It is estimated that the number of adults who are older than 65 years in the United States will more than double in the next 40 years. 1 Although much of this older population is currently classified as “young-old” (ie, 65-74 years old) as described by Leon, 2 by the year 2034, the majority of this population is projected to be older than 75 years. 1 This is not only the case in the United States. By 2040, the world population that is older than 80 years is projected to increase by 233%, and in the near future, it is hypothesized that the number of people older than 65 years will outnumber children younger than 5 years for the first time in history. 3
As discussed in this issue by Leon, 2 body functions progressively decline with age, and aging is a major risk factor for chronic degenerative diseases. The risk of problems with mobility 4 and physical inactivity5,6 also increase with age. Furthermore, older adults with type 2 diabetes are at greater risk for mobility-related disability compared with those without the disease. These are even greater concerns when the potential health care costs of an aging population are taken into account. 7
. . . the Look AHEAD trial suggests that older adults are very amenable to lifestyle intervention.
The Look AHEAD (Action for Health in Diabetes) trial is currently being conducted and, because of its long-term nature, includes an aging cohort of individuals. Participants for this trial are overweight and obese individuals with type 2 diabetes. 8 The primary hypothesis for this study is that an intensive lifestyle intervention focusing on reduced weight and increased physical activity will decrease cardiovascular events. 8 On starting this trial, 17% of participants were older than 65 years. 9 The study is in its 10th year and, now, more than 60% of these individuals are older than 65 years. 9 Not only does this randomized trial provide a potential model for a lifestyle program to improve the health of older adults, but its longitudinal nature also provides considerable insight into effective methods for increasing physical activity for these individuals. Finally, this study provides outcomes across multiple critical areas in an aging population.
Lifestyle Components Used by Look AHEAD
Goal Setting
Goals were set with participants for overall weight loss, caloric intake, and physical activity. 10 Participants were instructed to set small goals at first to make change more manageable. Over the course of time, these goals increased gradually approximating the ultimate study ideals. Specifically, in the case of physical activity, the larger study goal was 175 minutes of physical activity weekly by the end of 6 months. 8 To achieve this goal, participants were encouraged to walk for 50 minutes a week in the first month. The expectation for the number of minutes spent in physical activity then gradually increased. Participants were encouraged to aim for 200 minutes a week once the 175-minute goal was achieved. In addition to minutes spent in physical activity, participants also set goals to increase their daily steps to eventually reach 10,000 steps a day. 11
Self-Monitoring
Self-monitoring was used for recording daily food intake, weekly weight, minutes of physical activity, and step count. 10 Self-monitoring supports behavior change in multiple ways. First, it provides critical feedback to patients regarding their progress toward goals. It also assists the clinician in determining areas on which to intervene and help establish realistic goals in the future. Finally, self monitoring can increase motivation by providing evidence that the individual is successfully bringing about change in his or her life.
Social Support
During the beginning of the intervention, participants attended 3 group sessions per month that were designed to increase social support among each other. 10 Perhaps more important, they were also encouraged to seek social support from family members, other participants, and friends. For example, participants recruited walking partners to help keep them on track with their physical activity goals.
Increasing Activity Through Daily Living
The overall approach of this study was to support the incorporation of healthful behaviors into participants’ everyday routines. 10 For example, participants were encouraged to take the stairs instead of the elevator or park at the back of the parking lot instead of in the closest spot to reach the daily step goal. This approach increases the likelihood that the changes made will be long term and sustainable.
Outcomes
Weight
The primary aim of the lifestyle intervention was to achieve a sustained minimum weight loss of 7% of participant’s initial body weight. 8 Overall, individuals randomized to the intensive lifestyle intervention succeeded in losing an average of 8.6% of their initial body weight by 1 year. 12 Four-year results demonstrated that while the differences between treatment and control decreased, the treatment group experienced greater improvements in weight, fitness, glycemic control, and several cardiovascular risk factors. 10
Mobility
The Look AHEAD trial also assessed individuals for mobility. 13 Participants were classified into 4 states of mobility ranging from good mobility to severe limitations. Decreased mobility was an area of focus in this study because it puts individuals at risk for loss of independence 14 and decreased quality of life. 15 After adjusting for the baseline prevalence of severe limitation in mobility, individuals in the lifestyle intervention had a 48% reduction in mobility-related disability when compared with the control group. Both weight loss and improved fitness significantly mediated the effect of lifestyle intervention on slowing the loss of mobility. It is possible that the loss of weight also impacted overall fitness by increasing relative strength in lower limbs and improving overall balance. 16
Factors Associated With Improved Outcomes
Physical Activity
Adherence to treatment recommendations predicted weight loss. 17 Although adherence to meal replacement recommendations and attendance at treatment sessions were significant predictors of weight loss, adherence to the recommendations for physical activity was the strongest predictor of weight loss at 1 year. 18 Participants with the highest levels of physical activity lost 11.9% of their initial weight compared with 4.4% for those with the lowest physical activity. Although the study design did not allow for conclusions to be made regarding the reasons for weight loss, physical activity appears to play a critical role.
Increasing Age
Consistent with findings from other interventions, 19 the oldest participants lost significantly more weight than the youngest participants. Likewise, those who were older attended more treatment sessions, had more contacts with treatment staff, and self-reported greater behavioral adherence to the intervention. It was suggested that the older participants (age 65-74 years) may simply have more time to devote to the lifestyle intervention or motivation to improve health may be higher in this age-group. Overall, this finding is encouraging given that this group is at increased risk in terms of both morbidity and mortality.
Conclusion
The review in this issue by Leon 2 provides an excellent summary of the importance of physical activity in an aging population. Additional evidence from the Look AHEAD trial suggests that older adults are very amenable to lifestyle intervention. 17 Not only do these adults lose more weight and adhere to the intervention to a greater degree than their younger counterparts, they are also at decreased risk for mobility-related disability than those not actively engaged in a lifestyle intervention. These results clearly show that increasing levels of physical activity is and will be an important area of focus especially given the aging nature of the global population.