Aquatic treadmill training reduces blood pressure reactivity to physical stress.
OBJECTIVE
Endurance exercise may reduce blood pressure and improve vasodilatory capacity, thereby blunting the hypertensive response to stress. Therefore, we sought to test the efficacy of a novel model of low-impact endurance training, the aquatic treadmill (ATM), to improve blood pressure (BP) parameters.


METHODS
Sixty sedentary adults were randomized to 12-wk of either ATM (n = 36 [19 males and 17 females], 41 ± 2 yr, 173.58 ± 1.58 cm, 93.19 ± 3.15 kg) or land-based treadmill (LTM, n = 24 [11 males, 13 females], 42 ± 2 yr, 170.39 ± 1.94 cm, 88.14 ± 3.6 kg) training, three sessions per week, progressing to 500 kcal per session, 85% VO2max. The maximal Bruce treadmill test protocol was performed before and after training with BP measured before, at the end of each stage, and for 5 min after exercise testing. Twelve subjects (five ATM and seven LTM) volunteered for biopsies of the vastus lateralis before and after training, and muscle samples were assessed for endothelial nitric oxide synthase content. Data collected during exercise testing were analyzed using group by training ANCOVA repeated across training, α = 0.05.


RESULTS
ATM but not LTM training significantly reduced resting diastolic BP (-3.2 mm Hg), exercise systolic BP (range 9-18.2 mm Hg lower for each exercise stage), diastolic BP (3.2-8.1 mm Hg), mean arterial pressure (4.8-8.3 mm Hg, lower than LTM posttraining), and pulse pressure (7.5-15 mm Hg) during stages of exercise stress and recovery (P < 0.05). In addition, an increase (+31%) in skeletal muscle endothelial nitric oxide synthase content after training (P < 0.05) occurred in only the ATM group. Body mass (-1.27 kg) and VO2max (+3.6 mL · kg(-1) · min(-1)) changes were significant for both groups (P < 0.001).


CONCLUSIONS
ATM training can reduce BP reactivity to physical stress.
1Department of Health and Kinesiology, Texas A&M University, College Station, TX; and 2Cardiovascular Research Center, University of Virginia, Charlottesville, VA.
Brad S
BS
Lambert
Nicholas P
NP
Greene
Alex T
AT
Carradine
Dustin P
DP
Joubert
James D
JD
Fluckey
Steven E
SE
Riechman
Stephen F
SF
Crouse
D000328:Adult; D001794:Blood Pressure / Q000502:physiology*; D015992:Body Mass Index; D004727:Endothelium / Q000201:enzymology; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000201:enzymology; D019001:Nitric Oxide Synthase / Q000032:analysis; D010806:Physical Education and Training / Q000379:methods*; D010807:Physical Endurance / Q000502:physiology; D013312:Stress, Physiological / Q000502:physiology*
D019001:Nitric Oxide Synthase