Increasing daily walking lowers blood pressure in postmenopausal women.

PURPOSE: The American College of Sports Medicine and the Centers for Disease Control and Prevention (ACSM-CDC) recommend 30 min of daily moderate-intensity physical activity for health; however, the effectiveness of this recommendation in lowering blood pressure (BP) in hypertensives is unclear. The present study tested the hypothesis that walking activity following the ACSM-CDC physical activity recommendation would lower BP in postmenopausal women with high BP. METHODS: Resting BP was measured in 24 postmenopausal women with borderline to stage 1 hypertension at baseline, 12 wk, and 24 wk. Fifteen women in the exercise (EX) group walked 3 km.d-1 above their daily lifestyle walking, whereas 9 women in the control (CON) group did not change their activity. Walking activity was self-measured with a pedometer in both groups. RESULTS: Resting systolic BP was reduced in the EX group after 12 wk by 6 mm Hg (P < 0.005) and was further reduced by 5 mm Hg at the end of 24 wk (P < 0.005). There was no change in diastolic BP with walking. The CON group experienced no change in BP at either 12 or 24 wk. Body mass was modestly reduced by 1.3 kg in the EX group after 24 wk (P < 0.05); however, it was not correlated with the change in BP. There were no changes in selected variables known to impact BP including percent body fat, fasting plasma insulin, or dietary intake. CONCLUSION: In conclusion, a 24-wk walking program meeting the ACSM-CDC physical activity recommendation is effective in lowering systolic BP in postmenopausal women with borderline to stage 1 hypertension.

Brozek two-compartment model under-estimates body fat in black female athletes.

The purpose of this study was to compare percentage body fat (%BF) values of black female athletes calculated using the Heymsfield four-compartment (4C), Brozek two-compartment (2C) and Schutte models. Eleven collegiate athletes underwent total body water (TBW) assessment, hydrostatic weighing (HW) and dual energy X-ray absorptiometry (DXA). Repeated-measures ANOVA determined that the 4C model yielded %BF values (16.2 +/- 1.5%) that were higher than the Brozek model (13.6 +/- 1.7%) but similar to the Schutte model (16.7 +/- 1.6%). The fat-free mass density of the athletes (1.109 +/- 0. 002 kg l-1) was significantly higher than the value 1.1 kg l-1 assumed by the 2C model. We conclude that in lean black female athletes, the Brozek 2C model under-estimates %BF, and that, if only HW is available, the Schutte model should be used to estimate %BF.

The effects of blood lactate concentration on perception of effort during graded and steady state treadmill exercise.

Studies have reported that ratings of perceived exertion (RPE) are a valid tool for exercise prescription when blood lactate concentration (BLC) is used as the intensity criterion. However, few have studied the relationship between RPE and BLC during commonly used graded exercise tests (GXTs) and simulated exercise training. The purpose of this study was to determine if the RPE: BLC relationship is transferable across GXTs and a steady state exercise trial (SST). Thirteen healthy males (25+/-5.3yrs) completed two maximal treadmill tests (Bruce and Balke protocols) followed by a SST which consisted of approximately 8 minutes of exercise at each of two intensities (approximately 40% and 70% maximal heart rate reserve). BLCs and other physiological measures were compared at matched RPEs across the GXTs and SST trial at each exercise intensity using a two-way repeated measures ANOVA. There were no significant differences in BLC at a matched RPE across the exercise trials at the lower exercise intensity with the BLCs being 1.5+/-0.3, 1.6+/-0.6 and 1.3+/-0.3 mM, respectively. However, at the higher exercise intensity BLCs were significantly lower during the Balke GXT compared to the Bruce GXT and SST (1.8+/-0.6, 2.8+/-1.8 and 3.0+/-0.8 mM, p < 0.05). These results suggest that the RPE: BLC relationship may be protocol dependent during graded exercise testing as it was only transferable from the Bruce GXT to the exercise training setting at intensities in the typical prescription range of 50-85% of VO2max.