JORDANSTOWN, NORTHERN IRELAND. Conventional wisdom has it that exercise, to be an effective health measure, must be vigorous and sustained. A team of researchers from three British universities now challenges this assumption. Their study involved 21 middle-aged, sedentary, moderately overweight men and women. Sedentary was defined as having engaged in less than 20 minutes of planned exercise per week during the preceding 3 months. The study participants were randomized (in a cross-over design) to 1 of 2 groups. The first group undertook brisk walking for 30 minutes 5 days a week for 6 weeks. The second group took 3 daily walks (separated by at least 3 hours) of 10 minutes each 5 days a week for 6 weeks. The trial was followed by a 2-week period of no walking after which the first group walked for 3 x 10 minutes while the second group walked for 30 minutes at a time.
Both protocols were effective in increasing blood levels of HDL (good) cholesterol while decreasing levels of total cholesterol and triglycerides. They also were equally effective in reducing tension, anxiety, and diastolic blood pressure (by 1.5 mm Hg). The 10-minute walk program produced a greater increase in maximal oxygen uptake than the 30-minute program (14.2% versus 3.8%).
The researchers conclude that 3 10-minute bouts of brisk walking throughout the day for 5 days a week are
at least as effective as a daily 30-minute walk in reducing anxiety and tension, and in reducing
cardiovascular risk in previously sedentary individuals.