NLM Citation ID:
14718319 (PubMed)
Full Source Title:
Archives of Internal Medicine
Publication Type:
Clinical Trial; Journal Article; Randomized Controlled Trial
Language:
English
Author Affiliation:
Divisions of Cardiology, Geriatric Medicine, and General Internal Medicine,
Department of Medicine, Duke Center for Living, Center for Health Policy
Research, Durham, NC 27710, USA. Cris.Slentz@duke.edu
Authors:
Slentz CA; Duscha BD; Johnson JL; Ketchum K; Aiken LB; Samsa GP; Houmard JA;
Bales CW; Kraus WE
Abstract:
BACKGROUND: Obesity is a major health problem due, in part, to physical
inactivity. The amount of activity needed to prevent weight gain is unknown.
OBJECTIVE: To determine the effects of different amounts and intensities of
exercise training. DESIGN: Randomized controlled trial (February 1999-July
2002).Setting and PARTICIPANTS: Sedentary, overweight men and women (aged 40-65
years) with mild to moderate dyslipidemia were recruited from Durham, NC, and
surrounding communities. INTERVENTIONS: Eight-month exercise program with 3
groups: (1) high amount/vigorous intensity (calorically equivalent to
approximately 20 miles [32.0 km] of jogging per week at 65%-80% peak oxygen
consumption); (2) low amount/vigorous intensity (equivalent to approximately 12
miles [19.2 km] of jogging per week at 65%-80%), and (3) low amount/moderate
intensity (equivalent to approximately 12 miles [19.2 km] of walking per week at
40%-55%). Subjects were counseled not to change their diet and were encouraged
to maintain body weight. MAIN OUTCOME MEASURES: Body weight, body composition
(via skinfolds), and waist circumference. RESULTS: Of 302 subjects screened, 182
met criteria and were randomized and 120 completed the study. There was a
significant (P<.05) dose-response relationship between amount of exercise and
amount of weight loss and fat mass loss. The high-amount/vigorous-intensity
group lost significantly more body mass (in mean [SD] kilograms) and fat mass
(in mean [SD] kilograms) (-2.9 [2.8] and -4.8 [3.0], respectively) than the
low-amount/moderate-intensity group (-0.9 [1.8] and -2.0 [2.6], respectively),
the low-amount/vigorous-intensity group (-0.6 [2.0] and -2.5 [3.4],
respectively), and the controls (+1.0 [2.1] and +0.4 [3.0], respectively). Both
low-amount groups had significantly greater improvements than controls but were
not different from each other. Compared with controls, all exercise groups
significantly decreased abdominal, minimal waist, and hip circumference
measurements. There were no significant changes in dietary intake for any group.
CONCLUSIONS: In nondieting, overweight subjects, the controls gained weight,
both low-amount exercise groups lost weight and fat, and the high-amount group
lost more of each in a dose-response manner. These findings strongly suggest
that, absent changes in diet, a higher amount of activity is necessary for
weight maintenance and that the positive caloric imbalance observed in the
overweight controls is small and can be reversed by a modest amount of exercise.
Most individuals can accomplish this by walking 30 minutes every day.
Additional Subjects:
Grant ID:
HL-57354 HL NHLBI
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