Aerobic or Resistance Exercise, or Both, in Dieting Obese Older Adults

Abstract

Background: Obesity causes frailty in older adults; however, weight loss might accelerate age-related loss of muscle and bone mass and resultant sarcopenia and osteopenia.

Methods: In this clinical trial involving 160 obese older adults, we evaluated the effectiveness of several exercise modes in reversing frailty and preventing reduction in muscle and bone mass induced by weight loss. Participants were randomly assigned to a weight-management program plus one of three exercise programs - aerobic training, resistance training, or combined aerobic and resistance training - or to a control group (no weight-management or exercise program). The primary outcome was the change in Physical Performance Test score from baseline to 6 months (scores range from 0 to 36 points; higher scores indicate better performance). Secondary outcomes included changes in other frailty measures, body composition, bone mineral density, and physical functions.

Results: A total of 141 participants completed the study. The Physical Performance Test score increased more in the combination group than in the aerobic and resistance groups (27.9 to 33.4 points [21% increase] vs. 29.3 to 33.2 points [14% increase] and 28.8 to 32.7 points [14% increase], respectively; P=0.01 and P=0.02 after Bonferroni correction); the scores increased more in all exercise groups than in the control group (P<0.001 for between-group comparisons). Peak oxygen consumption (milliliters per kilogram of body weight per minute) increased more in the combination and aerobic groups (17.2 to 20.3 [17% increase] and 17.6 to 20.9 [18% increase], respectively) than in the resistance group (17.0 to 18.3 [8% increase]) (P<0.001 for both comparisons). Strength increased more in the combination and resistance groups (272 to 320 kg [18% increase] and 288 to 337 kg [19% increase], respectively) than in the aerobic group (265 to 270 kg [4% increase]) (P<0.001 for both comparisons). Body weight decreased by 9% in all exercise groups but did not change significantly in the control group. Lean mass decreased less in the combination and resistance groups than in the aerobic group (56.5 to 54.8 kg [3% decrease] and 58.1 to 57.1 kg [2% decrease], respectively, vs. 55.0 to 52.3 kg [5% decrease]), as did bone mineral density at the total hip (grams per square centimeter; 1.010 to 0.996 [1% decrease] and 1.047 to 1.041 [0.5% decrease], respectively, vs. 1.018 to 0.991 [3% decrease]) (P<0.05 for all comparisons). Exercise-related adverse events included musculoskeletal injuries.

Conclusions: Of the methods tested, weight loss plus combined aerobic and resistance exercise was the most effective in improving functional status of obese older adults. (Funded by the National Institutes of Health; LITOE ClinicalTrials.gov number, NCT01065636 .).

Figure 1. Screening, Randomization, and Follow-up

The study groups included a control group that received neither a weight-management nor an exercise intervention and three exercise groups: a group that received aerobic exercise training (aerobic group), a group that received resistance exercise training (resistance group), and a group that received combined aerobic and resistance exercise training (combination group); all three exercise groups also participated in a weight-management program.

Figure 2. (facing page). Mean Percentage Changes in Physical Function, Lean Mass, and BMD at the Total Hip during the Interventions

Measures of physical function included the Physical Performance Test (PPT; scores range from 0 to 36, with higher scores indicating better functional status), peak oxygen consumption, Functional Status Questionnaire (FSQ; scores range from 0 to 36, with higher scores indicating better functional status), and strength (measured as total one-repetition maximum [i.e., the total of the maximum weight a participant can lift, in one attempt, in the biceps curl, bench press, seated row, knee extension, knee flexion, and leg press]). Scores on the PPT were used as an objective measure of frailty (primary outcome), and scores on the FSQ were used as a subjective measure of frailty. The asterisk indicates P<0.05 for the comparison with the control group, the dagger P<0.05 for the comparison with the aerobic group, and the double dagger P<0.05 for the comparison with the resistance group. Percentage changes are presented as least-squares–adjusted means; T bars indicate standard errors. BMD denotes bone mineral density.

Figure 3. Mean Percent Changes in Body Weight during the Interventions

Percent changes are presented as least-squares–adjusted means; I bars indicate standard errors.