Key result
Walking 4.8 km per day at 4.8 km/h or 8.0 km/h significantly increased high-density lipoprotein cholesterol by 0.08 mmol/L (P<0.05) in sedentary women, independent of cardiorespiratory fitness gains.
Why the study?
Does walking at different intensities improve fitness and cardiovascular risk factors in sedentary premenopausal women?
RCT (n=102)
Randomized
No
Does walking at different intensities improve fitness and cardiovascular risk factors in sedentary premenopausal women?
Vigorous exercise is not necessary for women to obtain meaningful improvements in their lipoprotein profile, as lower-intensity walking produces equally favorable changes.
Answers are grounded in this paper and cite their sources.
Supports moderate walking for HDL gains in sedentary women; extends evidence that benefits occur independent of intensity or fitness gains.
Objective. —We studied whether the quantity and quality of walking necessary to decrease the risk of cardiovascular disease among women differed substantially from that required to improve cardiorespiratory fitness. Design. —A randomized, controlled, dose-response clinical trial with a follow-up of 24 weeks. Setting. —A private, nonprofit biomedical research facility. Participants. —One hundred two sedentary premenopausal women, 20 to 40 years of age, were randomized to one of four treatment groups; 59 completed the study (16 aerobic walkers [8.0-km/h group], 12 brisk walkers [6.4-km/h group], 18 strollers [4.8-km/h group], and 13 sedentary controls). Eighty-one percent were white, 17% black, and 2% Hispanic. Intervention. —Intervention groups walked 4.8 km per day, 5 days per week at 8.0 km/h, 6.4 km/h, or 4.8 km/h on a tartan-surfaced, 1.6-km track for 24 weeks. Main Outcome Measures. —Fitness (determined by maximal oxygen uptake) and cardiovascular risk factors (determined by resting blood pressure and serum lipid and lipoprotein levels). Results. —As compared with controls, maximal oxygen uptake increased significantly (P<.0001) and in a dose-response manner (aerobic walkers>brisk walkers>strollers). In contrast, high-density lipoprotein cholesterol concentrations were not dose related and increased significantly (P<.05) and to the same extent among women who experienced considerable improvements in their physical fitness (8.0-km/h group, +0.08 mmol/L) and those who had only minimal improvements in fitness (4.8-km/h group, +0.08 mmol/L). High-density lipoprotein cholesterol also increased among the 6.4-km/h group, but did not attain statistical significance (+0.06 mmol/L;P=.06). Dietary patterns revealed no significant differences among groups. Conclusion. —Thus, we conclude that vigorous exercise is not necessary for women to obtain meaningful improvements in their lipoprotein profile. Walking at intensities that do not have a major impact on cardiorespiratory fitness may nonetheless produce equally favorable changes in the cardiovascular risk profile. (JAMA. 1991;266:3295-3299)
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John J. Duncan (1991) conducted an RCT in Sedentary lifestyle (n=102). Walking at different intensities (8.0 km/h, 6.4 km/h, or 4.8 km/h) vs. Sedentary controls was evaluated on Fitness (maximal oxygen uptake) and cardiovascular risk factors (resting blood pressure and serum lipid and lipoprotein levels) (p=<.0001). Walking 4.8 km per day at 4.8 km/h or 8.0 km/h significantly increased high-density lipoprotein cholesterol by 0.08 mmol/L (P<0.05) in sedentary women, independent of cardiorespiratory fitness gains.
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