News & Views from the Editor-in-Chief - L. Bruce Gladden
This month I am drawing attention to three diverse studies. First, Sternfeld et al. mined data in the multi-racial/ethnic SWAN (Study of Women's Health Across the Nation) cohort to address the issue of how healthy lifestyle behaviors, including regular physical activity, healthy diet and abstaining from smoking, during midlife, relate to physical functioning, assessed by standard physical performance tests, later in life. Their most important conclusion was that, although the combination of all three behaviors is associated with better functioning, by far the best benefit results from physical activity. The clinical and public health implication of this finding is that identifying effective strategies for promoting regular physical activity in midlife will help to reduce the risk of loss of independence in the elderly, at least for women.
Morville and colleagues investigated metabolic adaptations including substrate utilization and mobilization in six older men after they cycled 2706 km in 14 days. Both maximal fat oxidation and maximal aerobic power were reduced by 6%. The available data from muscle biopsies, and blood samples at rest before and after the cycling, pointed toward a slight increase in insulin resistance and decrease of lipid mobilization despite the 10.5 h of daily exercise. In concert with this observation, a marked reduction in plasma fatty acid concentration was noted at rest, probably explaining the decreased fat oxidation and increased reliance on carbohydrate during exercise. Overall the data implied that this extreme exercise event was probably at, if not just over, the upper level of the capacity for prolonged repeated exercise in these 60+ year old men.
Finally, Allison and coworkers found that brief bouts of vigorous stair climbing are a practical and time-efficient method to boost cardiorespiratory fitness. The investigated protocols required a time commitment of only 10 min including warm-up, cool-down and recovery periods between bouts. One protocol consisted of three, 20-s (3 × 20 s) bouts of continuous climbing (~3 stories per effort) and the other involved repeatedly ascending and descending a single flight of stairs for 1 min, repeated three times. Both protocols improved maximal oxygen uptake in previously untrained young women, when performed three times per week for six weeks. The ~1-MET improvement in cardiorespiratory fitness elicited by the 3 × 20 s protocol was similar to what the authors previously reported after a similar cycling-based protocol. These results suggest that interval training can be taken "out of the lab" and adapted to residential and workplace settings.
L. Bruce Gladden
School of Kinesiology