Rapid vascular modifications to localized rhythmic handgrip training and detraining: vascular conditioning and deconditioning.
Despite the evidence describing the rapid vascular function modifications to commencement and cessation of large muscle exercises (i.e. cycling), no studies examined the time-course vascular modifications to localized training and detraining. This study aimed to examine the effects of 4-week rhythmic handgrip exercise training and 2-week detraining on reactive hyperemic forearm blood flow and vascular resistance in 11 young men. Rhythmic handgrip exercise was performed in the non-dominant forearm for 20 min/day, 5 days/week, at 60% of maximum voluntary contraction for 4 weeks, followed by 2 weeks of no training. Forearm blood flow and vascular resistance were evaluated, in both arms, at rest and following arterial occlusion. These vascular function indices were obtained in five visits; before, after 1 and 4 week(s) of training as well as after 1 and 2 week(s) of training cessation. Resting cardiovascular measures were not altered during the study period. A 2 (arms) x 5 (visits) ANOVA revealed significant arms-by-visits interactions for reactive hyperemic forearm blood flow (p = 0.02) and vascular resistance (p = 0.02). Subsequent comparison demonstrated increased trained forearm reactive hyperemic blood flow 1 week after training, then returned to pre-training values 1 week following training cessation. In contrast, vascular resistance decreased 1 week after training commencement, only to return to pretraining level 1 week after training cessation. These results indicate a rapid, unilateral improvement in regional reactive hyperemic blood flow and vascular resistance following localized exercise-training. However, the improvements are transient and return to pretraining levels 1 week after detraining.
Alomari
Mahmoud A
MA
Division of Physical Therapy, Department of Allied Medical Sciences, Jordan University of Science and Technology, Irbid, Jordan. Alomari@just.edu.jo
Mekary
Rania A
RA
Welsch
Michael A
MA
D000222:Adaptation, Physiological / Q000502:physiology; D000328:Adult; D015444:Exercise / Q000502:physiology*; D005542:Forearm / Q000098:blood supply; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D008297:Male; D012039:Regional Blood Flow / Q000502:physiology*; D013997:Time Factors; D014655:Vascular Resistance / Q000502:physiology*