Effects of intermittent exercise during prolonged sitting on executive function, cerebrovascular, and psychological response: a randomized crossover trial.

Emerging evidence indicates that acute bouts of uninterrupted prolonged sitting decrease cerebral blood flow and impair executive function. Few studies have investigated the use of feasible sedentary behavior interruptions to attenuate these effects. This study aimed to investigate the effects of intermittent half-squat exercises during prolonged sitting on executive function. Twenty participants (45% women, 21 ± 1 yr) were randomized to sit for 3 h 1) without any interruptions (control) or 2) with 1 min half-squats every 20 min (exercise). Executive function was determined using the Color Word Stroop Test (CWST) and Trail Making Test-B (TMT-B). Subjective feelings of arousal and measures of fatigue, concentration, and motivation were evaluated. Internal carotid artery (ICA) blood flow was measured using Doppler ultrasound. There was a significant interaction effect for correct response times with the incongruent CWST (P < 0.01), which were 3.5% faster in the exercise and 4.2% slower in the control over 3 h of sitting. There was also a significant interaction effect for TMT-B completion times (P < 0.01), which were 10.0% faster in the exercise and 8.8% slower in the control. Exercise suppressed decreases in concentration with a significant interaction effect (-28.7% vs. -9.2% for control vs. exercise, P = 0.048) and increases in mental fatigue with a significant interaction effect (285% vs. 157% for control vs. exercise, P < 0.04). These changes may have been related to changes in ICA blood flow, which had a significant interaction effect (P = 0.087). These results suggest that a simple strategy like intermittent squat exercises could help to maintain executive function during prolonged sitting.NEW & NOTEWORTHY We assessed executive function, cardiovascular, and cerebrovascular responses during 3-h prolonged sitting, with or without an exercise interruption (1 min squats every 20 min). Compared to uninterrupted sitting, exercise interruption suppressed sitting-induced reductions in cerebral blood flow and impairments in executive function. These results demonstrated the efficacy of a half-squat intervention for individuals seeking to preserve cognition during prolonged sitting, which may be useful in environments with limited resources such as the workplace.

Impact of Wearing Graduated Compression Stockings on Psychological and Physiological Responses during Prolonged Sitting.

We investigated the impact of wearing vs. not wearing graduated compression stockings on psychological and physiological responses in 18 healthy young people (12 men and six women) during 3 h prolonged sitting. Profiled of Mood States (POMS) scores did not show marked differences between with and without stockings. A 3 h sit significantly decreased saliva cortisol in both conditions; with no differences between conditions. Wearing stockings suppressed a subjective uncomfortable sensation (e.g., pain; fatigue; swelling) in the lower limbs, as assessed by visual analogue scale (VAS). Increase in heart rate at 1 h and 3 h was significantly greater without than with stockings. In addition, high-frequency oscillations (HF: 0.15⁻0.4 Hz), used as an indicator of parasympathetic nerve activity, showed higher values with than without stockings throughout the 3 h sitting period-significantly higher at 1 h. When data for both conditions were pooled pre-to-post changes in saliva cortisol were positively associated with higher uncomfortable sensations of VAS in the lower limbs and negatively associated with changes in the Vigor subscale of POMS. Collectively, these findings suggest that wearing graduated compression stockings may benefit from subjective comfort and increased parasympathetic nerve activity.

Comparisons of energy cost and economical walking speed at various gradients in healthy, active younger and older adults.

BACKGROUND/OBJECTIVE: Oxygen consumption during walking per unit distance (Cw ; mL/kg/m) is known to be greater for older adults than younger adults, although its underlying process is controversial. METHODS: We measured the Cw values at six gait speeds from 30 m/min to 105 m/min on level ground and gradient slopes (±5%) in healthy younger and older male adults. A quadratic approximation was applied for a relationship between Cw and gait speeds (v; m/min). It gives a U-shaped Cw -v relationship, which includes a particular gait speed minimizing the Cw , the so-called economical speed (ES). The age-related difference of the Cw -v relationship was assessed by comparisons of ES and/or Cw . RESULTS: A significantly greater Cw at 30 m/min and slower ES were found for older adults at the downhill gradient, suggesting that a combination of leftward and upward shifts of the Cw -v relationship was found at that gradient. Only a slower ES was found for older adults at the uphill gradient, suggesting that a leftward shift was found for older adults at that gradient. Neither a significant leftward nor an upward shift was found at the level gradient. Leg length significantly correlated to the ES for younger adults at the level and downhill gradients, while such a significant relationship was observed only at the level gradient for older adults. The maximal quadriceps muscle strength significantly correlated to the ES for older adults at all gradients, but not for younger adults. CONCLUSION: The age-related alteration of the Cw -v relationship depends on the gradient, and its related factors were different between age groups.