Isometric Exercise Improves Redox Balance and Blood Pressure in Hypertensive Adults.
The aim of this study was to investigate the hemodynamic, oxidative stress (OS), and nitric oxide (NO) responses to a submaximal isometric exercise session (IES) involving large muscle mass. Fourteen hypertensive (HTG: age: 35.9 ± 8.1 years, height: 1.73 ± 0.10 m, total body mass: 78.0 ± 15.8 kg) and 10 normotensive (NTG: age: 41.1 ± 9.4 years, height: 1.71 ± 0.12 m, total body mass: 82.3 ± 22.4 kg) participants performed 2 experimental sessions in the leg press and bench press: i) control session and ii) 8 sets x 1 min contraction at 30% maximal voluntary isometric contraction with 2 min rest interval. Blood pressure (BP) was measured at rest and during 60 min postexercise. Blood samples were collected at rest, immediately after the session, and 60 min postexercise. NO was obtained through the Griess reaction method. OS parameters were analyzed using commercial kits. A repeated-measures ANOVA with Bonferroni's post hoc was used to analyze all dependent variables. A significant decrease in systolic BP was observed only for HTG at 45 min and 60 min postexercise (baseline vs. 45 min: p = 0.03, Δ% = 4.44%; vs. 60 min: p = 0.018, Δ% = 5.58%). NO increased immediately postexercise only for HTG (p = 0.008, Δ% = 16.44%). Regarding OS parameters, TBARS presented a significant reduction 60 min after the IES for NTG and HTG; catalase increased in both groups. The data showed that only 8 minutes of IES with a large muscle mass elicits an elevated pro-oxidant activity leading to a greater NO bioavailability, increases antioxidant reaction, and consequently reduces BP in hypertensive patients.