Key result
A morning bout of moderate-intensity exercise followed by uninterrupted sitting resulted in higher average middle cerebral artery velocity over 8 hours compared to prolonged sitting alone.
Why the study?
Preventing declines in cerebral blood flow is important for maintaining brain health with aging, but the effects of morning exercise with or without walking breaks during prolonged sitting were unknown.
Does morning moderate-intensity exercise with or without walking breaks improve cerebral blood velocity over 8 hours in overweight/obese older adults compared to prolonged sitting?
RCT (n=12)
crossover
Does morning moderate-intensity exercise with or without walking breaks improve cerebral blood velocity over 8 hours in overweight/obese older adults compared to prolonged sitting?
A morning bout of moderate-intensity exercise mitigates the decline in cerebral blood flow associated with prolonged sitting in older adults.
Answers are grounded in this paper and cite their sources.
May enhance cerebral perfusion during prolonged sitting; hypothesis-generating for cerebrovascular health and requires confirmation before clinical adoption.
Preventing declines in cerebral blood flow is important for maintaining optimal brain health with aging. We compared the effects of a morning bout of moderate-intensity exercise, with and without subsequent light-intensity walking breaks from sitting, on cerebral blood velocity over 8 h in older adults. In a randomized crossover trial, overweight/obese older adults ( n = 12, 70 ± 7 yr; 30.4 ± 4.3 kg/m 2 ), completed three acute conditions (6-day washout); SIT: prolonged sitting (8 h, control); EX+SIT: sitting (1 h), moderate-intensity walking (30 min), followed by uninterrupted sitting (6.5 h); and EX + BR: sitting (1 h), moderate-intensity walking (30 min), followed by sitting (6.5 h) interrupted with 3 min of light-intensity walking every 30 min. Bilateral middle cerebral artery velocities (MCAv) were determined using transcranial Doppler at 13 time points across the day. The temporal pattern and average MCAv over 8 h was determined. The pattern of MCAv over 8 h was a negative linear trend in SIT ( P < 0.001), but a positive quadratic trend in EX + SIT ( P < 0.001) and EX + BR ( P < 0.01). Afternoon time points in SIT were lower than baseline within condition ( P ≤ 0.001 for all). A morning dip in MCAv was observed in EX + SIT and EX + BR ( P < 0.05 relative to baseline), but afternoon time points were not significantly lower than baseline. The average MCAv over 8 h was higher in EX + SIT than SIT ( P = 0.007) or EX + BR ( P = 0.024). Uninterrupted sitting should be avoided, and moderate-intensity exercise should be encouraged for the daily maintenance of cerebral blood flow in older adults. The clinical implications of maintaining adequate cerebral blood flow include the delivery of vital oxygen and nutrients to the brain. NEW & NOTEWORTHY This is the first study to measure the combined effects of an exercise bout with breaks in sitting on cerebral blood velocity in older adults. Using frequent recordings over an 8-h period, we have performed a novel analysis of the pattern of cerebral blood velocity, adjusting for concurrent measures of mean arterial pressure and other potential confounders in a linear mixed effects regression.
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Wheeler et al. (2019) conducted an RCT in overweight/obese older adults (n=12). Morning moderate-intensity exercise with or without subsequent walking breaks vs. Prolonged sitting (8 h) was evaluated on Average bilateral middle cerebral artery velocity (MCAv) over 8 h (p=0.007). A morning bout of moderate-intensity exercise followed by uninterrupted sitting resulted in higher average middle cerebral artery velocity over 8 hours compared to prolonged sitting alone (P=0.007).
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