DAILY EXERCISE DOES NOT ALTER CEREBRAL BLOOD FLOW REGULATION DURING TILT IN OLDER ADULTS AFTER TWO WEEKS OF BEDREST

Abstract Bedrest is associated with cardiovascular and cerebrovascular changes that are linked to a greater prevalence of orthostatic intolerance; however, much what we know from bedrest trials comes young adults. How older adults respond extended periods activity restriction not well understood. The current work tested the hypothesis impaired control cerebral blood flow in following could be attenuated by regular exercise. Twenty-two (55-65 years, 11 women) participated randomized controlled trial involving 14 days continuous 6-degree head-down bedrest. cohort was an exercise intervention (EX), daily aerobic, high-intensity interval, resistance training, or group (CON), passive manual therapy. Cerebral velocity, cardiac output, arterial pressure were measured continuously during 80-degree head-up tilt protocol for up 15 minutes. Responses peripheral vascular beds quantified (cerebral: area product (RAP); peripheral: total (TPR)). Following bedrest, both supine RAP TPR elevated (p< 0.01), no effect training. In addition, number participants who complete minutes increased 3 (8 EX, 7 CON). these non-finishers, dropped ~20% ~15% final 2 tilt, difference between groups. These data suggest multimodal training insufficient prevent regulation observed 14-day