Zachary S. Zeigler

Effects of standing and light-intensity activity on ambulatory blood pressure

PURPOSE This study aimed to compare ambulatory blood pressure (ABP) response to accumulated standing (STAND), cycling (CYCLE), and walking (WALK) to a sitting-only (SIT) day in adults. METHODS Nine overweight or obese (body mass index, 28.7 ± 2.7 kg · m(-2)) adults (30 ± 15 yr) participated in this randomized crossover full-factorial study. Four conditions (WALK, STAND, CYCLE, and SIT) were randomly performed 1 wk apart. WALK, STAND, and CYCLE conditions consisted of progressively increasing activity time to accumulate 2.5 h during an 8-h simulated workday. WALK (1.0 mph) and STAND (0.0 mph) were completed on a treadmill placed underneath a standing-height desk. During CYCLE, participants pedaled on a Monark cycle ergometer at a cadence and energy expenditure equivalent to WALK. Participants remained seated during the SIT condition. Participants wore an ABP cuff from 0800 h until 2200 h on all conditions. Linear mixed models were used to test condition differences in systolic (SBP) and diastolic (DBP) blood pressure. Chi-square was used to detect frequency difference of BP load. RESULTS There was a whole-day (during and after work hours) SBP and DBP treatment effect (P < 0.01). Systolic blood pressure during STAND (132 ± 17 mm Hg), WALK (133 ± 17 mm Hg), and CYCLE (130 ± 16 mm Hg) were lower compared with that during SIT (137 ± 17 mm Hg) (all P < 0.01). CYCLE was lower than STAND (P = 0.04) and WALK (P < 0.01). For DBP, only CYCLE (69 ± 12 mm Hg) was lower than SIT (71 ± 13 mm Hg; P < 0.01). Compared with SIT, WALK, STAND, and CYCLE reduced SBP load by 4%, 4%, and 13%, respectively (all P < 0.01). CONCLUSIONS Compared with sitting, accumulating 2.5 h of light-intensity physical activity or standing during an 8-h workday may reduce ABP during and after work hours.

Effects of Standing and Light-Intensity Walking and Cycling on 24-h Glucose.

PURPOSE This study aimed to compare 24-h and postprandial glucose responses to incremental intervals of standing (STAND), walking (WALK), and cycling (CYCLE) to a sit-only (SIT) condition. METHODS Nine overweight/obese (body mass index = 29 ± 3 kg·m) adults (30 ± 15 yr) participated in this randomized crossover full-factorial study, with each condition performed 1 wk apart. STAND, CYCLE, and WALK intervals increased from 10 to 30 min·h (2.5 h total) during an 8-h workday. WALK (1.0 mph) and STAND were matched for upright time, and WALK and CYCLE were matched for energy expenditure (~2 METs). Continuous interstitial glucose monitoring was performed for 24 h to include the 8-h workday (LAB), after-work evening hours (EVE), and sleep (SLEEP). Three 2-h postprandial periods were also analyzed. Linear mixed models were used to test for condition differences. RESULTS Compared with SIT (5.7 ± 1.0 mmol·L), mean 24-h glucose during STAND (5.4 ± 0.9 mmol·L) and WALK (5.3 ± 0.9 mmol·L) were lower, and CYCLE (5.1 ± 1.0 mmol·L) was lower than all other conditions (all P < 0.001). During LAB and EVE, mean glucose was lower for STAND, WALK, and CYCLE compared with SIT (P < 0.001). During SLEEP, the mean glucose for CYCLE was lower than all other conditions (P < 0.001). Compared with SIT, cumulative 6-h postprandial mean glucose was 5%-12% lower (P < 0.001) during STAND, WALK, and CYCLE, and 6-h postprandial glucose integrated area under the curve was 24% lower during WALK (P < 0.05) and 44% lower during CYCLE (P < 0.001). CONCLUSIONS Replacing sitting with regular intervals of standing or light-intensity activity during an 8-h workday reduces 24-h and postprandial glucose. These effects persist during evening hours, with CYCLE having the largest and most sustained effect.

Walking Workstation Use Reduces Ambulatory Blood Pressure in Adults with Prehypertension

BACKGROUND The acute effect of low-intensity walking on blood pressure (BP) is unclear. PURPOSE To determine if the acute use of a walking workstation reduces ambulatory blood pressure (ABP) in prehypertensive men and women. METHODS Ten prehypertensive adults participated in a randomized, cross-over study that included a control workday and a walking workstation workday. ABP was measured for 7 hour during the workday and for 6 hour after work. RESULTS Both systolic BP (SBP) (134 ± 14 vs. 137 ± 16 mmHg; P = .027) and diastolic BP (DBP) (79 ± 10 vs. 82 ± 12 mmHg; P = .001) were lower on the walking workstation day. Postwork hours (4:00 PM-10:00 PM), SBP (129 ± 13 vs. 133 ± 14 mmHg; P = .008), and DBP (74 ± 11 vs. 78 ± 13 mmHg; P = .001) were also lower on the walking workstation day. DBP load was significantly lower during the walking workstation day, with only 14% of the readings above 90 mmHg compared with 22% of the control day readings (P = .037). CONCLUSION Accumulation of very-light-intensity physical activity (~2 METs) over the course of a single work day using a walking workstation may reduce BP burden in prehypertensive individuals.

Acute effects on cognitive performance following bouts of standing and light-intensity physical activity in a simulated workplace environment

OBJECTIVES To compare acute cognitive effects following bouts of standing (STAND), cycling (CYCLE) and walking (WALK) to a sit-only (SIT) condition. DESIGN Randomized cross-over full-factorial study. METHODS Nine overweight (BMI=29±3kg/m2) adults (30±15years; 7 females, 2 males) completed four conditions (SIT, STAND, WALK and CYCLE) across a 6h period with a 7days washout period between conditions. SIT consisted of uninterrupted sitting. Experimental conditions included intermittent bouts of standing (STAND), cycling (CYCLE) and walking (WALK). A cognitive performance battery (Cogstate) was completed twice in a seated position following bouts of standing and light-intensity physical activity. Mixed-effects models compared between-condition differences in standardized score (z-score), accuracy (%), and speed (log10ms). RESULTS Cognitive performance z-score and accuracy measures were higher during STAND, CYCLE and WALK (P<0.05) conditions compared to the SIT condition. CYCLE was better than other experimental conditions. CONCLUSIONS Compared to uninterrupted sitting, short bouts of standing or light-intensity cycling and walking may improve acute cognitive performance.

Acute effects of whole-body vibration with resistance exercise on postexercise blood pressure and oxygen consumption in prehypertensive adults

Background/Objective Research on the acute health effects of whole-body vibration with resistance exercise (WBV + RE) for clinical populations is limited. This randomized crossover trial evaluated postexercise hypotension and excess postexercise oxygen consumption (EPOC) in response to three conditions: WBV + RE, RE alone, and control (CON) in 11 prehypertensive (systolic/diastolic blood pressure: 120–139/80–89 mmHg) adults. Methods Following a 12-hour fast with no exercise for the previous 24 hours, resting VO2 and blood pressure (BP) were measured. WBV + RE was performed while standing barefoot on a vibration platform (Pneumex Pro-Vibe) and lifting a bar of 10% body weight. Fifteen repetitions of nine exercises were performed using a 1-minute–to-30-second exercise:rest ratio. RE was identical to WBV + RE but without vibration. During CON, participants remained seated for 15 minutes. Following exercise, VO2 was measured continuously and BP every 15 minutes for 3 hours. Results Postexercise hypotension and EPOC were significantly different for WBV + RE compared with RE and CON (p <0.001). Postexercise systolic BP was significantly lower for WBV + RE as compared with RE or CON, while diastolic BP was lower for both WBV + RE and RE compared with CON (p < 0.001; WBV + RE: 124 ± 2/72 ± 6 mmHg; RE: 126 ± 2/71 ± 6 mmHg; CON: 128 ± 2/73 ± 6 mmHg). EPOC was significantly (p < 0.001) higher at 15 minutes postexercise for WBV + RE as compared with RE. Conclusion Compared with RE alone, a single bout of WBV + RE resulted in a greater postexercise hypotension response and higher EPOC.